My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

On Monday, 15 August 2016 10:50:06 UTC+1, Dan S. MacAbre wrote:

My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

No room stat would explain why it's always on You need one, and would expect 2 with 2 zones.


NT

Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't think
they could even find it. There is a timer, which has, AFAIK, worked
until now. A mechanical clock type, with a red/blue wheel for manual
control in the top right corner. Even when that is switched off, the
boiler still lights, but I thought the boiler got its power from the timer.

wrote:
On Monday, 15 August 2016 10:50:06 UTC+1, Dan S. MacAbre wrote:

My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

No room stat would explain why it's always on You need one, and would expect 2 with 2 zones.


I'd have thought so, but if there is one, it's not on any wall anywhere.
I'll have to see how it's connected - I've a suspicion that it's
powered open all the time.

They say that it's only just started doing it, but maybe they've only
just noticed it. Funny thing is, even when you unplug the power to the
timer and boiler, the pump still runs. It has its own power supply, and
didn't stop till I pulled out another plug in the boiler cupboard. I
think the whole thing is probably completely wrong.


NT

On Monday, 15 August 2016 11:38:30 UTC+1, Dan S. MacAbre wrote:
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't think
they could even find it.

Turning the primary temp down could cause it

There is a timer, which has, AFAIK, worked
until now. A mechanical clock type, with a red/blue wheel for manual
control in the top right corner. Even when that is switched off, the
boiler still lights, but I thought the boiler got its power from the timer.

Wired wrong then.


NT

On Monday, 15 August 2016 11:43:10 UTC+1, Dan S. MacAbre wrote:
tabbypurr wrote:
On Monday, 15 August 2016 10:50:06 UTC+1, Dan S. MacAbre wrote:

My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

No room stat would explain why it's always on You need one, and would expect 2 with 2 zones.


I'd have thought so, but if there is one, it's not on any wall anywhere.
I'll have to see how it's connected - I've a suspicion that it's
powered open all the time.

Sounds like the system is wired up utterly wrong.

They say that it's only just started doing it, but maybe they've only
just noticed it. Funny thing is, even when you unplug the power to the
timer and boiler, the pump still runs. It has its own power supply, and
didn't stop till I pulled out another plug in the boiler cupboard.

A separate overrun to the boiler could explain that.

I
think the whole thing is probably completely wrong.

I suspect so.


NT

wrote:
On Monday, 15 August 2016 11:38:30 UTC+1, Dan S. MacAbre wrote:
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't think
they could even find it.

Turning the primary temp down could cause it

There is a timer, which has, AFAIK, worked
until now. A mechanical clock type, with a red/blue wheel for manual
control in the top right corner. Even when that is switched off, the
boiler still lights, but I thought the boiler got its power from the timer.

Wired wrong then.


I think it probably is. It's that sort of house - everything you look
at has been done wrong. Previous owner had a reputation for bodging
everything, unfortunately.


NT

On Mon, 15 Aug 2016 11:38:28 +0100
"Dan S. MacAbre" wrote:

Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought
the best thing to do, besides just switching it off for now, would
be to try and work out how it's all wired together, and then work
out possible causes. I've only so far had time for a quick look,
but something has struck me as odd. They have two motorised zone
valves, but there is no room thermostat anywhere. I'd always
thought that each zone valve responded to a thermostat. Is there
any valid configuration that has two zone valves, but no room
thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than the boiler thermostat? If it is that is what is causing the
problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't
think they could even find it. There is a timer, which has, AFAIK,
worked until now. A mechanical clock type, with a red/blue wheel for
manual control in the top right corner. Even when that is switched
off, the boiler still lights, but I thought the boiler got its power
from the timer.

Is there a junction box somewhere near the boiler or 'stat? That might
help provide information by identifying the wires connected inside it.
Otherwise, you will indeed have to do what I had to do earlier this
year, start from scratch with a pad and pencil, and make your own
schematic. Keep careful note of changes of colours where wires from
different components are connected.

The sudden change in operation could possibly indicate that one of the
zone valves has failed Open, thereby telling the boiler to run all the
time. Also, what temp. is the boiler thermostat set at?

Look for as much information as possible on components, ie Manufacturer,
model, etc so that you can look them up online.

But two zone valves and no room 'stat is a real puzzle. What controls
them?
I am intrigued.

--
Davey.

Davey wrote:
On Mon, 15 Aug 2016 11:38:28 +0100
"Dan S. MacAbre" wrote:

Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought
the best thing to do, besides just switching it off for now, would
be to try and work out how it's all wired together, and then work
out possible causes. I've only so far had time for a quick look,
but something has struck me as odd. They have two motorised zone
valves, but there is no room thermostat anywhere. I'd always
thought that each zone valve responded to a thermostat. Is there
any valid configuration that has two zone valves, but no room
thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than the boiler thermostat? If it is that is what is causing the
problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't
think they could even find it. There is a timer, which has, AFAIK,
worked until now. A mechanical clock type, with a red/blue wheel for
manual control in the top right corner. Even when that is switched
off, the boiler still lights, but I thought the boiler got its power
from the timer.

Is there a junction box somewhere near the boiler or 'stat? That might
help provide information by identifying the wires connected inside it.

I think it's in the void, along with the pump. I'll have a look at it
this evening.

Otherwise, you will indeed have to do what I had to do earlier this
year, start from scratch with a pad and pencil, and make your own
schematic. Keep careful note of changes of colours where wires from
different components are connected.

I did that with my own CH maybe ten years ago. Quite instructive.

The sudden change in operation could possibly indicate that one of the
zone valves has failed Open, thereby telling the boiler to run all the
time. Also, what temp. is the boiler thermostat set at?

ATM, the thermostat is switched to off. Still comes on, though.

Look for as much information as possible on components, ie Manufacturer,
model, etc so that you can look them up online.

But two zone valves and no room 'stat is a real puzzle. What controls
them?
I am intrigued.


I'll find out later.

On Mon, 15 Aug 2016 12:27:01 +0100
"Dan S. MacAbre" wrote:

Also, what temp. is the boiler thermostat set at?

ATM, the thermostat is switched to off. Still comes on, though.

That does not sound right at all. You definitely need to start
sketching, including the boiler internal wiring! There may be no limit
to the bodges done to the system.

--
Davey.

Davey wrote:
On Mon, 15 Aug 2016 12:27:01 +0100
"Dan S. MacAbre" wrote:

Also, what temp. is the boiler thermostat set at?

ATM, the thermostat is switched to off. Still comes on, though.

That does not sound right at all. You definitely need to start
sketching, including the boiler internal wiring! There may be no limit
to the bodges done to the system.


Yes, this seems the oddest symptom to me. I've no doubt that it is
wired incorrectly, but as long as the boiler stat was working, no-one
noticed. And, it seems, the timer did actually switch it on and off as
required, since mum says that putting the timer switch in the
permanently off position no longer does anything. Now, perhaps,
something is broken in the boiler. Maybe some frost protection device
or a PCB, if it even has one? It's an old Glow-Worm thing, but to me
that means there should be fewer things to go wrong :-)

On Monday, 15 August 2016 12:43:49 UTC+1, Dan S. MacAbre wrote:
Davey wrote:
On Mon, 15 Aug 2016 12:27:01 +0100
"Dan S. MacAbre" wrote:

Also, what temp. is the boiler thermostat set at?

ATM, the thermostat is switched to off. Still comes on, though.

That does not sound right at all. You definitely need to start
sketching, including the boiler internal wiring! There may be no limit
to the bodges done to the system.


Yes, this seems the oddest symptom to me. I've no doubt that it is
wired incorrectly, but as long as the boiler stat was working, no-one
noticed. And, it seems, the timer did actually switch it on and off as
required, since mum says that putting the timer switch in the
permanently off position no longer does anything. Now, perhaps,
something is broken in the boiler. Maybe some frost protection device
or a PCB, if it even has one? It's an old Glow-Worm thing, but to me
that means there should be fewer things to go wrong :-)

Well at least the worm is still glowing.


NT

wrote:
On Monday, 15 August 2016 12:43:49 UTC+1, Dan S. MacAbre wrote:
Davey wrote:
On Mon, 15 Aug 2016 12:27:01 +0100
"Dan S. MacAbre" wrote:

Also, what temp. is the boiler thermostat set at?

ATM, the thermostat is switched to off. Still comes on, though.

That does not sound right at all. You definitely need to start
sketching, including the boiler internal wiring! There may be no limit
to the bodges done to the system.


Yes, this seems the oddest symptom to me. I've no doubt that it is
wired incorrectly, but as long as the boiler stat was working, no-one
noticed. And, it seems, the timer did actually switch it on and off as
required, since mum says that putting the timer switch in the
permanently off position no longer does anything. Now, perhaps,
something is broken in the boiler. Maybe some frost protection device
or a PCB, if it even has one? It's an old Glow-Worm thing, but to me
that means there should be fewer things to go wrong :-)

Well at least the worm is still glowing.


:-) Too much, right now.


NT

On 15/08/16 12:19, Dan S. MacAbre wrote:
everything you look at has been done wrong. Previous owner had a
reputation for bodging everything, unfortunately.

Reminds me of years and years ago. Bloke said 'my car battery keeps
going flat ever since I fitted these air horns'

Well there was supposed to be a relay, that the horn push would
activate, that would then drive the air horns. Somehow the relay was
permanently on across the battery and the contacts were in series with
the horn push and the horn itself.

So it worked...BUT....

....a prime example of swap the wires till it works...


--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

On Mon, 15 Aug 2016 12:20:46 +0100, Davey
wrote:

On Mon, 15 Aug 2016 11:38:28 +0100
"Dan S. MacAbre" wrote:

Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought
the best thing to do, besides just switching it off for now, would
be to try and work out how it's all wired together, and then work
out possible causes. I've only so far had time for a quick look,
but something has struck me as odd. They have two motorised zone
valves, but there is no room thermostat anywhere. I'd always
thought that each zone valve responded to a thermostat. Is there
any valid configuration that has two zone valves, but no room
thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than the boiler thermostat? If it is that is what is causing the
problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't
think they could even find it. There is a timer, which has, AFAIK,
worked until now. A mechanical clock type, with a red/blue wheel for
manual control in the top right corner. Even when that is switched
off, the boiler still lights, but I thought the boiler got its power
from the timer.

Is there a junction box somewhere near the boiler or 'stat? That might
help provide information by identifying the wires connected inside it.
Otherwise, you will indeed have to do what I had to do earlier this
year, start from scratch with a pad and pencil, and make your own
schematic. Keep careful note of changes of colours where wires from
different components are connected.

The sudden change in operation could possibly indicate that one of the
zone valves has failed Open, thereby telling the boiler to run all the
time. Also, what temp. is the boiler thermostat set at?

Look for as much information as possible on components, ie Manufacturer,
model, etc so that you can look them up online.

But two zone valves and no room 'stat is a real puzzle. What controls
them?
I am intrigued.

It sounds as if they have a Randall time clock controlling both of
them, probably got a cylinder stat in the DHW circuit. I wonder if
they have TRVs on the rads?

No room stat? Well gas was cheap and installers were stingy in those
days.

The Randell does allow the DHW to run independently of the CH, but not
vice-versa, even though a typical fully pumped "S" plan does allow it
given the chance.


Dan,
One valve should open when "hot water only" is selected on the time
clock and both should open when HW+CH is selected

When each valve is open (the motor remains energized and stalled by
design) a cam operates a micro switch and powers the gas-valve and
pump. The two micro switches are in parallel. My guess is one of these
micro switches is stuck, or a valve is stuck open



--

Graham.

%Profound_observation%

The Natural Philosopher wrote:
On 15/08/16 12:19, Dan S. MacAbre wrote:
everything you look at has been done wrong. Previous owner had a
reputation for bodging everything, unfortunately.

Reminds me of years and years ago. Bloke said 'my car battery keeps
going flat ever since I fitted these air horns'

Well there was supposed to be a relay, that the horn push would
activate, that would then drive the air horns. Somehow the relay was
permanently on across the battery and the contacts were in series with
the horn push and the horn itself.

Good grief!

So it worked...BUT....

...a prime example of swap the wires till it works...

Graham. wrote:
On Mon, 15 Aug 2016 12:20:46 +0100, Davey
wrote:

On Mon, 15 Aug 2016 11:38:28 +0100
"Dan S. MacAbre" wrote:

Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought
the best thing to do, besides just switching it off for now, would
be to try and work out how it's all wired together, and then work
out possible causes. I've only so far had time for a quick look,
but something has struck me as odd. They have two motorised zone
valves, but there is no room thermostat anywhere. I'd always
thought that each zone valve responded to a thermostat. Is there
any valid configuration that has two zone valves, but no room
thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than the boiler thermostat? If it is that is what is causing the
problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't
think they could even find it. There is a timer, which has, AFAIK,
worked until now. A mechanical clock type, with a red/blue wheel for
manual control in the top right corner. Even when that is switched
off, the boiler still lights, but I thought the boiler got its power
from the timer.

Is there a junction box somewhere near the boiler or 'stat? That might
help provide information by identifying the wires connected inside it.
Otherwise, you will indeed have to do what I had to do earlier this
year, start from scratch with a pad and pencil, and make your own
schematic. Keep careful note of changes of colours where wires from
different components are connected.

The sudden change in operation could possibly indicate that one of the
zone valves has failed Open, thereby telling the boiler to run all the
time. Also, what temp. is the boiler thermostat set at?

Look for as much information as possible on components, ie Manufacturer,
model, etc so that you can look them up online.

But two zone valves and no room 'stat is a real puzzle. What controls
them?
I am intrigued.

It sounds as if they have a Randall time clock controlling both of
them, probably got a cylinder stat in the DHW circuit. I wonder if
they have TRVs on the rads?

I searched that, and they do indeed have one of those. Big wheel in the
middle, little red and blue one in the corner.

No room stat? Well gas was cheap and installers were stingy in those
days.

So it's possible there is a workable, if less than optimal,
configuration that can work without the room stat?

The Randell does allow the DHW to run independently of the CH, but not
vice-versa, even though a typical fully pumped "S" plan does allow it
given the chance.


Dan,
One valve should open when "hot water only" is selected on the time
clock and both should open when HW+CH is selected

When each valve is open (the motor remains energized and stalled by
design) a cam operates a micro switch and powers the gas-valve and
pump. The two micro switches are in parallel. My guess is one of these
micro switches is stuck, or a valve is stuck open


Okay, I think I can easily check that, since there are two of them to
compare against each other.

On 15/08/2016 11:38, Dan S. MacAbre wrote:
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and neither
of them has admitted to changing the tank stat. I don't think they could
even find it. There is a timer, which has, AFAIK, worked until now. A
mechanical clock type, with a red/blue wheel for manual control in the
top right corner. Even when that is switched off, the boiler still
lights, but I thought the boiler got its power from the timer.

Depends on the system. If it's an S-Plan system, each zone valve should
be driven by a thermostat (one room stat and one tank stat) and the
boiler is then switched on by contacts on the zone valves which close
when the valves are fully open. It's quite a common fault for a valve to
stick open and turn on the heating even when there's no demand from
either of the stats.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 15/08/2016 11:43, Dan S. MacAbre wrote:
wrote:
On Monday, 15 August 2016 10:50:06 UTC+1, Dan S. MacAbre wrote:

My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

No room stat would explain why it's always on You need one, and
would expect 2 with 2 zones.


I'd have thought so, but if there is one, it's not on any wall anywhere.
I'll have to see how it's connected - I've a suspicion that it's powered
open all the time.

They say that it's only just started doing it, but maybe they've only
just noticed it. Funny thing is, even when you unplug the power to the
timer and boiler, the pump still runs. It has its own power supply, and
didn't stop till I pulled out another plug in the boiler cupboard. I
think the whole thing is probably completely wrong.

That certainly sounds wrong! the whole system should be powered from a
single switched fused spur so that it can be isolated in one operation.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Roger Mills wrote:
On 15/08/2016 11:38, Dan S. MacAbre wrote:
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to
try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and neither
of them has admitted to changing the tank stat. I don't think they could
even find it. There is a timer, which has, AFAIK, worked until now. A
mechanical clock type, with a red/blue wheel for manual control in the
top right corner. Even when that is switched off, the boiler still
lights, but I thought the boiler got its power from the timer.

Depends on the system. If it's an S-Plan system, each zone valve should
be driven by a thermostat (one room stat and one tank stat) and the
boiler is then switched on by contacts on the zone valves which close
when the valves are fully open. It's quite a common fault for a valve to
stick open and turn on the heating even when there's no demand from
either of the stats.

Okay, I'll check the zone valves later. I'm curious to see how the CH
one is controlled with no room stat.

On 15/08/16 13:26, Dan S. MacAbre wrote:
So it's possible there is a workable, if less than optimal,
configuration that can work without the room stat?

Absolutely. I have run like that. Its not ideal BUT with TRV's as they
shut down one by one,. assuming you have a bypass so some flow occurs,
what you end up with is a very hot short loop that isnt going to the
rads at all, and the boiler thermostat itself will cycle on and off to
keep that loop at the boiler stat temp - say 60C or whatever.

I will say as general advice, that if you are reasonably knowledgeable
about matters electrical. faced with a bodged rats nest, often the
simplest thing to do is disconnect everything and document where wires
go, and rewire the whole system according to one of the 'standard plans'

Adding an overall stat is not hard with todays RF ones. Neither is
fitting TRV's to a drained down CH system.

You may need to add a motorised valves but that's not rocket science,
and a documented control box where all the wires come together is a nice
touch.


--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

On 15/08/16 13:35, Roger Mills wrote:
the whole system should be powered from a single switched fused spur so
that it can be isolated in one operation.

I think that is actually mandatory with building control these days.


--
Those who want slavery should have the grace to name it by its proper
name. They must face the full meaning of that which they are advocating
or condoning; the full, exact, specific meaning of collectivism, of its
logical implications, of the principles upon which it is based, and of
the ultimate consequences to which these principles will lead. They must
face it, then decide whether this is what they want or not.

Ayn Rand.

Roger Mills wrote:
On 15/08/2016 11:43, Dan S. MacAbre wrote:
wrote:
On Monday, 15 August 2016 10:50:06 UTC+1, Dan S. MacAbre wrote:

My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to
try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

No room stat would explain why it's always on You need one, and
would expect 2 with 2 zones.


I'd have thought so, but if there is one, it's not on any wall anywhere.
I'll have to see how it's connected - I've a suspicion that it's powered
open all the time.

They say that it's only just started doing it, but maybe they've only
just noticed it. Funny thing is, even when you unplug the power to the
timer and boiler, the pump still runs. It has its own power supply, and
didn't stop till I pulled out another plug in the boiler cupboard. I
think the whole thing is probably completely wrong.

That certainly sounds wrong! the whole system should be powered from a
single switched fused spur so that it can be isolated in one operation.

Yes, the manual for the boiler has several wiring diagrams, two of which
use two zone valves. All of the diagrams start with the power coming
from the timer. This thing actually has power for the boiler/timer
coming from a round-pin socket/plug. All the other sockets in the
house, and even the other one that sends power up into the void to the
pump are square pin. It's an 80's house, so the guy probably just had a
spare round-pin socket, and used that. Or something.

On Monday, 15 August 2016 11:27:33 UTC+1, Muddymike wrote:
Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Or has it fallen off the HW cylinder so is measuring air temp not cylinder temp?

Owain

The Natural Philosopher wrote:
On 15/08/16 13:26, Dan S. MacAbre wrote:
So it's possible there is a workable, if less than optimal,
configuration that can work without the room stat?

Absolutely. I have run like that. Its not ideal BUT with TRV's as they
shut down one by one,. assuming you have a bypass so some flow occurs,
what you end up with is a very hot short loop that isnt going to the
rads at all, and the boiler thermostat itself will cycle on and off to
keep that loop at the boiler stat temp - say 60C or whatever.

I will say as general advice, that if you are reasonably knowledgeable
about matters electrical. faced with a bodged rats nest, often the
simplest thing to do is disconnect everything and document where wires
go, and rewire the whole system according to one of the 'standard plans'

Adding an overall stat is not hard with todays RF ones. Neither is
fitting TRV's to a drained down CH system.

You may need to add a motorised valves but that's not rocket science,
and a documented control box where all the wires come together is a nice
touch.

Fortunately, the boiler, pump, and valves are physically close,
electrically linked through a big hole in the boiler cupboard ceiling.
So working out how it is wired shouldn't take too much time. Each
radiator does have a TRV, and I'll just have to hope that there is,
indeed, a bypass somewhere.

Interesting to know that the room stat isn't strictly necessary.

wrote:
On Monday, 15 August 2016 11:27:33 UTC+1, Muddymike wrote:
Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Or has it fallen off the HW cylinder so is measuring air temp not cylinder temp?

Owain


Another thing to check :-)

On Mon, 15 Aug 2016 13:40:15 +0100
The Natural Philosopher wrote:

I will say as general advice, that if you are reasonably
knowledgeable about matters electrical. faced with a bodged rats
nest, often the simplest thing to do is disconnect everything and
document where wires go, and rewire the whole system according to one
of the 'standard plans'

The system I had to work out earlier had apparently been attended to by
a professional, but it had a dead room 'stat, and had lots of other
weird wiring mistakes. Although it had normal separate DHW and CH
systems, if one came on, they both came on.
I worked out what went where, then figured out what wires to move to
where to make it work.
It was the thread "Heating System Puzzle", if you wanted to look it up.

--
Davey.

On 15/08/2016 12:20, Davey wrote:
On Mon, 15 Aug 2016 11:38:28 +0100
"Dan S. MacAbre" wrote:

Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought
the best thing to do, besides just switching it off for now, would
be to try and work out how it's all wired together, and then work
out possible causes. I've only so far had time for a quick look,
but something has struck me as odd. They have two motorised zone
valves, but there is no room thermostat anywhere. I'd always
thought that each zone valve responded to a thermostat. Is there
any valid configuration that has two zone valves, but no room
thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than the boiler thermostat? If it is that is what is causing the
problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't
think they could even find it. There is a timer, which has, AFAIK,
worked until now. A mechanical clock type, with a red/blue wheel for
manual control in the top right corner. Even when that is switched
off, the boiler still lights, but I thought the boiler got its power
from the timer.

It could be that the tank stat has failed and never says OK any more...
my parents did that once with scalding water from the taps.

It is an odd failure mode for midsummer. More often you get the opposite
that the CH is satisfied so it fails to heat the hot water.

Is there a junction box somewhere near the boiler or 'stat? That might
help provide information by identifying the wires connected inside it.
Otherwise, you will indeed have to do what I had to do earlier this
year, start from scratch with a pad and pencil, and make your own
schematic. Keep careful note of changes of colours where wires from
different components are connected.

The sudden change in operation could possibly indicate that one of the
zone valves has failed Open, thereby telling the boiler to run all the
time. Also, what temp. is the boiler thermostat set at?

Look for as much information as possible on components, ie Manufacturer,
model, etc so that you can look them up online.

But two zone valves and no room 'stat is a real puzzle. What controls
them?

Could be other timers but then you would have more than one system timer
but there should be thermostats somewhere. My parents is like that with
thermostats and zones being switched at night to only heat the bedroom
in use (and with a lower set point).

The usual cause of sudden changes resulting in either mad hot hot water
or insanely hot radiators is that a valve has stopped opening or closing
when commanded to do so by the thermostat (or the thermostat is dead).

Find the thermostats and then you might be able to test it by altering
the settings.

I am intrigued.

--
Regards,
Martin Brown

On Monday, 15 August 2016 13:26:11 UTC+1, Dan S. MacAbre wrote:
Graham. wrote:

No room stat? Well gas was cheap and installers were stingy in those
days.

So it's possible there is a workable, if less than optimal,
configuration that can work without the room stat?

It is possible if you have all TRVs, but the result is varying temp and wasted gas. It's a right bodge.


NT

On Monday, 15 August 2016 13:43:13 UTC+1, Dan S. MacAbre wrote:

from the timer. This thing actually has power for the boiler/timer
coming from a round-pin socket/plug. All the other sockets in the
house, and even the other one that sends power up into the void to the
pump are square pin. It's an 80's house, so the guy probably just had a
spare round-pin socket, and used that. Or something.

Nothing wrong with round pin plugs, they're occasionally used to prevent other things getting plugged in somewhere.


NT

If its only just started to occur, I'd think incorrect wiring an unlikely
cause, more like a fused together contact in the clock itself. I've seen
these actually brake off and wedge it all up solid, but this was years ago,
how old is this boiler. If you see Fred Flinstone as the service engineer,
its probably time for a new one!
Brian

--
From the Sofa of Brian Gaff Reply address is active
Remember, if you don't like where I post
or what I say, you don't have to
read my posts! :-)
wrote in message
...
On Monday, 15 August 2016 11:38:30 UTC+1, Dan S. MacAbre wrote:
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to
try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is
no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't think
they could even find it.

Turning the primary temp down could cause it

There is a timer, which has, AFAIK, worked
until now. A mechanical clock type, with a red/blue wheel for manual
control in the top right corner. Even when that is switched off, the
boiler still lights, but I thought the boiler got its power from the
timer.

Wired wrong then.


NT

On Mon, 15 Aug 2016 13:40:15 +0100, The Natural Philosopher
wrote:

On 15/08/16 13:26, Dan S. MacAbre wrote:
So it's possible there is a workable, if less than optimal,
configuration that can work without the room stat?

Absolutely. I have run like that. Its not ideal BUT with TRV's as they
shut down one by one,. assuming you have a bypass so some flow occurs,
what you end up with is a very hot short loop that isnt going to the
rads at all, and the boiler thermostat itself will cycle on and off to
keep that loop at the boiler stat temp - say 60C or whatever.

I will say as general advice, that if you are reasonably knowledgeable
about matters electrical. faced with a bodged rats nest, often the
simplest thing to do is disconnect everything and document where wires
go, and rewire the whole system according to one of the 'standard plans'

Adding an overall stat is not hard with todays RF ones. Neither is
fitting TRV's to a drained down CH system.

You may need to add a motorised valves but that's not rocket science,
and a documented control box where all the wires come together is a nice
touch.

Precisely what I must have been doing yesterday, 39 years ago,
according to this!

https://www.flickr.com/gp/g3zvt/Q8c247

I drew it as a schematic rather than a terminal to terminal
representation, because I understand diagrams better when drawn like
this.

Randall time switch and 2X Honeywell V4043 valves, apart from the room
stat it's probably exactly what the OP has got, and I hope it helps.




--

Graham.

%Profound_observation%

On 15/08/2016 15:38, wrote:
On Monday, 15 August 2016 13:43:13 UTC+1, Dan S. MacAbre wrote:

from the timer. This thing actually has power for the boiler/timer
coming from a round-pin socket/plug. All the other sockets in the
house, and even the other one that sends power up into the void to the
pump are square pin. It's an 80's house, so the guy probably just had a
spare round-pin socket, and used that. Or something.

Nothing wrong with round pin plugs, they're occasionally used to prevent other things getting plugged in somewhere.


NT

Nothing wrong with round pin plugs per se, except that as the plug has
no fuse protection in it, the circuit fuse or mcb will most likely be
rated in excess of that required for the boiler/timer unit and possibly
the flex connection to it.

--- news://freenews.netfront.net/ - complaints: ---

On 15/08/2016 13:50, Dan S. MacAbre wrote:


Fortunately, the boiler, pump, and valves are physically close,
electrically linked through a big hole in the boiler cupboard ceiling.
So working out how it is wired shouldn't take too much time. Each
radiator does have a TRV, and I'll just have to hope that there is,
indeed, a bypass somewhere.

Interesting to know that the room stat isn't strictly necessary.

It *is* necessary to meet current regs - but wouldn't have been when
this system was installed.

Current regs require "boiler interlock" - which means that the boiler
gets turned off when there's no demand from any of the zones. If you
just have TRVs and no room stat, the boiler wastes energy by keeping
itself hot when it doesn't need to.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Mon, 15 Aug 2016 16:18:44 +0100
Graham. wrote:

On Mon, 15 Aug 2016 13:40:15 +0100, The Natural Philosopher
wrote:

On 15/08/16 13:26, Dan S. MacAbre wrote:
So it's possible there is a workable, if less than optimal,
configuration that can work without the room stat?

Absolutely. I have run like that. Its not ideal BUT with TRV's as
they shut down one by one,. assuming you have a bypass so some flow
occurs, what you end up with is a very hot short loop that isnt
going to the rads at all, and the boiler thermostat itself will
cycle on and off to keep that loop at the boiler stat temp - say 60C
or whatever.

I will say as general advice, that if you are reasonably
knowledgeable about matters electrical. faced with a bodged rats
nest, often the simplest thing to do is disconnect everything and
document where wires go, and rewire the whole system according to
one of the 'standard plans'

Adding an overall stat is not hard with todays RF ones. Neither is
fitting TRV's to a drained down CH system.

You may need to add a motorised valves but that's not rocket
science, and a documented control box where all the wires come
together is a nice touch.

Precisely what I must have been doing yesterday, 39 years ago,
according to this!

https://www.flickr.com/gp/g3zvt/Q8c247

I drew it as a schematic rather than a terminal to terminal
representation, because I understand diagrams better when drawn like
this.


My one as described for my project started out like that, noting
cables and their colours, and then changed to a more formal
wires-and-terminals version as the wiring became clear(er).

One point worth making for the OP: Make sure you know where every cable
goes to at both ends. You can find devices of which you were totally
unaware! (believe me).

--
Davey.

On Mon, 15 Aug 2016 13:37:04 +0100, Dan S. MacAbre wrote:

Roger Mills wrote:
On 15/08/2016 11:38, Dan S. MacAbre wrote:
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to
try and work out how it's all wired together, and then work out
possible causes. I've only so far had time for a quick look, but
something has struck me as odd. They have two motorised zone valves,
but there is no room thermostat anywhere. I'd always thought that
each zone valve responded to a thermostat. Is there any valid
configuration that has two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher
than the boiler thermostat? If it is that is what is causing the
problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't think
they could even find it. There is a timer, which has, AFAIK, worked
until now. A mechanical clock type, with a red/blue wheel for manual
control in the top right corner. Even when that is switched off, the
boiler still lights, but I thought the boiler got its power from the
timer.

Depends on the system. If it's an S-Plan system, each zone valve should
be driven by a thermostat (one room stat and one tank stat) and the
boiler is then switched on by contacts on the zone valves which close
when the valves are fully open. It's quite a common fault for a valve
to stick open and turn on the heating even when there's no demand from
either of the stats.

Okay, I'll check the zone valves later. I'm curious to see how the CH
one is controlled with no room stat.

The boiler stat is left to do the temperature control. When TRVs are
fitted on all bar one radiator (or a heated towel rail) to provide a
permanent return loop, it works tolerably well although gas consumption
will be trivially higher than one with a room stat to shut off the boiler
completely when the room selected to 'pay the piper' has reached its
target temperature.

Upgrading a 30 to 50 year old CH & HW system using the classic
indestructible cast iron boiler with a room stat or two won't provide
much improvement in gas economy (by the time the stat(s) call for more
heat, the boiler and pipework will have cooled down (not stone cold,
admittedly but nevertheless enough to cause a lag in raising the radiator
temps) requiring the burner to run for an extra minute or three for the
system to come back up to temperature which will partially at least (if
not significantly) nullifying the efficiency gain of using room stat(s).

If you have a system using the new fangled lightweight destructible
condensing boilers, a room stat or three makes a lot more sense. On an
older system with a cast iron boiler and TRVs, the economies of adding
one or more room stats becomes questionable. This is one of those rare
cases where the saying, "If it ain't broke, don't fix it!" does actually
have some basis in fact. :-)

--
Johnny B Good

In article , Dan S. MacAbre
writes
Muddymike wrote:
On 15/08/2016 10:50, Dan S. MacAbre wrote:
My mum and Dad's boiler wants to stay on all the time. I thought the
best thing to do, besides just switching it off for now, would be to try
and work out how it's all wired together, and then work out possible
causes. I've only so far had time for a quick look, but something has
struck me as odd. They have two motorised zone valves, but there is no
room thermostat anywhere. I'd always thought that each zone valve
responded to a thermostat. Is there any valid configuration that has
two zone valves, but no room thermostat?

Is there a thermostat on the hot water tank? If so is it set higher than
the boiler thermostat? If it is that is what is causing the problem.

Mike

I'll check. This has apparently only just started happening, and
neither of them has admitted to changing the tank stat. I don't think
they could even find it. There is a timer, which has, AFAIK, worked
until now. A mechanical clock type, with a red/blue wheel for manual
control in the top right corner. Even when that is switched off, the
boiler still lights, but I thought the boiler got its power from the timer.
The boiler gets its power through the valves which get their power from
the timer (and normally through a room thermostat). Sounds like one of
the valve heads is U/S. I don't quite see the point of zone valves
without individual timers or thermostats. Are you sure they are not hot
water/central heating controllers?

--
bert

Upgrading a 30 to 50 year old CH & HW system using the classic
indestructible cast iron boiler with a room stat or two won't provide
much improvement in gas economy (by the time the stat(s) call for
more heat, the boiler and pipework will have cooled down (not stone
cold, admittedly but nevertheless enough to cause a lag in raising
the radiator temps) requiring the burner to run for an extra minute
or three for the system to come back up to temperature which will
partially at least (if not significantly) nullifying the efficiency
gain of using room stat(s).

If you have a system using the new fangled lightweight destructible
condensing boilers, a room stat or three makes a lot more sense. On
an older system with a cast iron boiler and TRVs, the economies of
adding one or more room stats becomes questionable. This is one of
those rare cases where the saying, "If it ain't broke, don't fix it!"
does actually have some basis in fact. :-)


And I was taken to task a while ago for saying the same thing...

Oh well, that's life.

--
Davey.

Davey Wrote in message:

Upgrading a 30 to 50 year old CH & HW system using the classic
indestructible cast iron boiler with a room stat or two won't provide
much improvement in gas economy (by the time the stat(s) call for
more heat, the boiler and pipework will have cooled down (not stone
cold, admittedly but nevertheless enough to cause a lag in raising
the radiator temps) requiring the burner to run for an extra minute
or three for the system to come back up to temperature which will
partially at least (if not significantly) nullifying the efficiency
gain of using room stat(s).

If you have a system using the new fangled lightweight destructible
condensing boilers, a room stat or three makes a lot more sense. On
an older system with a cast iron boiler and TRVs, the economies of
adding one or more room stats becomes questionable. This is one of
those rare cases where the saying, "If it ain't broke, don't fix it!"
does actually have some basis in fact. :-)


And I was taken to task a while ago for saying the same thing...



it certainly seemed to make significant difference here. (18
rads, most with TRVs , 5, hallway,landing and bathroom and toilet
without. Pumped CH, gravity HW)

No room stat, so heating on all the time the timer was on, 7 rads
pumping out heat, bits of the house getting hotter than
neccessary. Fitting a roomsat was a pretty cheap and easy
addition and did seem to contribute to lower bills the next
winter (always hard to judge these things, weathers not the same,
other things may change as well)


--
--
Chris French