I have a had a problem for a while now that my heating is constantly
on, I cant turn it off. Setting the t-stat down to min, the programmer
to "off" (for heating and h/w) makes no difference. It can stay on for
days, i usually have to power off the pump to turn off the heating.
What is strange is that in general the boiler does seem to respond well
the the t-stat and programmer - in that when i turn the t-stat all the
way up, the boiler ignites, turn down it goes out. Same for switching
between "off" and "constant" on the programmer. The problem is it
never stays off for long, it seems to turn itself on periodically (like
every 5/6 mins), stays on for a minute or two, then off again.

Does anyone have any idea what is going on?

Dont have any experience in this area, so dont know what info you need,
i'll stab at:

Boiler - hmm says "Apollo Fanfare" on it
Pump - Celsia
Valve - SwitchMaster (i *think* its a 3-way, well there are 3 pipes
going into it)
Programmer - SwitchMaster 900, mechanical (has both CH and HW switches)

All help very much appreciated!

Alex.

On 25 Mar 2006 07:10:56 -0800, Alex DV wrote:

I have a had a problem for a while now that my heating is constantly
on, I cant turn it off.

Do you have a frost stat?

never stays off for long, it seems to turn itself on periodically (like
every 5/6 mins), stays on for a minute or two, then off again.

Now I'm confused. You first said it doesn't go off, now you say it is
cycling.

--
Nigel M

What's a frost stat?

Sorry for the confusion. The heating is always on - ie the radiators
are always hot, but the boiler is on and off. So, to be clear. Right
now the programmer is set to off, and the therm is set to min. The
boiler is off. In a few mins the boiler will ignite by itself and stay
on for a few mins. Since the programmer is already "off" and the therm
already on "min" I cant "turn off" the boiler using those mechanisms (I
can hit the switch on the boiler itself which will turn it off, but
doesnt really get me anywhere). After a few mins the boiler will
swtich itself off. When in this state, if I flick the programmer to
constant, the boiler will come on. Or, if I set the therm to max, the
boiler will come on. If I turn the therm down, or switch programmer
off, the boiler will go off. However, after another 5 mins, whatever I
do, the boiler will come on.

So, Once its on of its own accord, i cant switch it off (the programmer
is already set to off, and therm to min).

If I've manually switched it on, then I can turn it off again.

Hope that makes things clearer.

On 25 Mar 2006 08:07:36 -0800, Alex DV wrote:

What's a frost stat?

A thermostat that overrides the whole system if there is a danger of
freezing. If so, it does this ...

now the programmer is set to off, and the therm is set to min. The
boiler is off. In a few mins the boiler will ignite by itself and stay
on for a few mins.

They are often mounted in a boiler room, and rely on being heated by
the boiler. So if you have recently put in a new boiler or flue, it
could be confused.

I've got a frost stat on my "landing" (it's actually a bungalow, but
YSWIM) set to 15 deg. It turns on the heating on cold nights.

--
Nigel M

On Sat, 25 Mar 2006 07:10:56 -0800, Alex DV wrote:

I have a had a problem for a while now that my heating is constantly
on, I cant turn it off. Setting the t-stat down to min, the programmer
to "off" (for heating and h/w) makes no difference. It can stay on for
days, i usually have to power off the pump to turn off the heating.
What is strange is that in general the boiler does seem to respond well
the the t-stat and programmer - in that when i turn the t-stat all the
way up, the boiler ignites, turn down it goes out. Same for switching
between "off" and "constant" on the programmer. The problem is it
never stays off for long, it seems to turn itself on periodically (like
every 5/6 mins), stays on for a minute or two, then off again.

Does anyone have any idea what is going on?

Dont have any experience in this area, so dont know what info you need,
i'll stab at:

Boiler - hmm says "Apollo Fanfare" on it
Pump - Celsia
Valve - SwitchMaster (i *think* its a 3-way, well there are 3 pipes
going into it)
Programmer - SwitchMaster 900, mechanical (has both CH and HW switches)

All help very much appreciated!

Alex.

The main FAQ has stuff on heating controls.
This could be a stuck 3 port valve (with just enough going to the HW to
keep it warm enough).

If you are not up to using a circuit tester you'll need some help.

First thing is to see if the programmer gives the correct output.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

The only other stat that I know of, apart from the room stat, is on the
hot water tank (currently set to 50 degrees).

I hadnt changed/installed anything until the problem occurred. Then
the one component i did think might be the problem was the programmer,
only because it was sooo old and grimey, so I have replaced that with a
new one. Although I followed the wiring diagrams there is a chance I
have wired it up wrong. But, as mentioned, I have tested and that does
appear to ignite/switch off the boiler in the expected way.

Thanks for the input thus far.

On Sat, 25 Mar 2006 08:36:18 -0800, Alex DV wrote:

The only other stat that I know of, apart from the room stat, is on the
hot water tank (currently set to 50 degrees).

I hadnt changed/installed anything until the problem occurred. Then
the one component i did think might be the problem was the programmer,
only because it was sooo old and grimey, so I have replaced that with a
new one. Although I followed the wiring diagrams there is a chance I
have wired it up wrong. But, as mentioned, I have tested and that does
appear to ignite/switch off the boiler in the expected way.

Thanks for the input thus far.

Well the next thing is to see if the tank and room stats give the right
signals.

Then proceed to see if the valve head moves in the right manner.
My guess is that the 3-port valve will be the most likely culprit.

Occasionally a boiler will fire when un-demanded the only one I'm aware
that do this are Vaillant VCWs combis, doubtless there are other models
which which could display this fault.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Turning both room and tank stats seem to ignite/turn off the boiler as
expected.

As for the valve, I have tried manually turning it, and it does turn
all the way round to the correct position (HW when HW is on Constant,
CH when CH is on Constant, CH when HW and CH are both on Constant).

An extra bit of information, I think the pump is always on - not sure
this is significant.

As ever, thanks for the responses so far, any further help very much
appreciated!

On Mon, 27 Mar 2006 07:56:49 -0800, Alex DV wrote:

Turning both room and tank stats seem to ignite/turn off the boiler as
expected.

As for the valve, I have tried manually turning it, and it does turn
all the way round to the correct position (HW when HW is on Constant,
CH when CH is on Constant, CH when HW and CH are both on Constant).

An extra bit of information, I think the pump is always on - not sure
this is significant.

As ever, thanks for the responses so far, any further help very much
appreciated!

The pump may be controlled by the boiler? I'm not familiar with the Apollo
Fanfare (from Thorn?).

As you mention that this valve move 'all the way round' it might be
something different form the 'standard' honeywell mid-position type.

Since moving the thermostats turned the boiler off maybe the problem is
that the wall thermostat is electrically OK but has become insensitive to
temperature?

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

maybe the problem is that the wall thermostat is electrically OK but has become insensitive to temperature?

Thats a very good point. How would I check that?

On 28 Mar 2006 02:34:38 -0800, "Alex DV" wrote:

|maybe the problem is that the wall thermostat is electrically OK but has become insensitive to temperature?
|
|Thats a very good point. How would I check that?

Twiddle the knob and see if it switches the heating on and off.
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

The message
from Dave Fawthrop contains these words:

|maybe the problem is that the wall thermostat is electrically OK but
has become insensitive to temperature?
|
|Thats a very good point. How would I check that?

Twiddle the knob and see if it switches the heating on and off.

That would test its sensitivity to twiddling - but not to temperature.

--
Skipweasel
Pay no attention to that man behind the curtain.

On Tue, 28 Mar 2006 12:12:14 +0100, Guy King wrote:

|The message
|from Dave Fawthrop contains these words:
|
| |maybe the problem is that the wall thermostat is electrically OK but
| has become insensitive to temperature?
| |
| |Thats a very good point. How would I check that?
|
| Twiddle the knob and see if it switches the heating on and off.

Perhaps I should have added "at about the temperature of the room"

|That would test its sensitivity to twiddling - but not to temperature.

That always works for me!
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

The message
from Dave Fawthrop contains these words:

| Twiddle the knob and see if it switches the heating on and off.

Perhaps I should have added "at about the temperature of the room"

|That would test its sensitivity to twiddling - but not to temperature.

That always works for me!

Twiddling a cold knob can be futile.

--
Skipweasel
Pay no attention to that man behind the curtain.

In message , Guy King
writes
The message
from Dave Fawthrop contains these words:

|maybe the problem is that the wall thermostat is electrically OK but
has become insensitive to temperature?
|
|Thats a very good point. How would I check that?

Twiddle the knob and see if it switches the heating on and off.

That would test its sensitivity to twiddling - but not to temperature.

Blowtorch

or rather - a hairdrier ?

--
geoff

On Tue, 28 Mar 2006 02:34:38 -0800, Alex DV wrote:

maybe the problem is that the wall thermostat is electrically OK but has become insensitive to temperature?

Thats a very good point. How would I check that?

1) Is there a large variation between the on click and off click?
2) If you set the heating on and then turn the thermostat down till it
nearly clicks off - what happens then?

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

1) Is there a large variation between the on click and off click?
No.

2) If you set the heating on and then turn the thermostat down till it
nearly clicks off - what happens then?
Boiler stays on until stat reaches stat's temp.

Ok, so after some days of investigations, I have more information.

I tried disconnecting the room stat, the programmer and the tank stat
(removing the L and N wire in each case). The result is that the pump
remains ON and the boiler continues to cycle, 5 mins off, 5 mins on.
My understanding was that the programmer feeds the power to the rest of
the system, so how did the pump continue ? Could this be a short
circuit? How did the boiler contine - is it on the same circuit as the
pump?

On Thu, 30 Mar 2006 13:04:47 -0800, Alex DV wrote:

1) Is there a large variation between the on click and off click?
No.

2) If you set the heating on and then turn the thermostat down till it
nearly clicks off - what happens then?
Boiler stays on until stat reaches stat's temp.

Ok, so after some days of investigations, I have more information.

I tried disconnecting the room stat, the programmer and the tank stat
(removing the L and N wire in each case). The result is that the pump
remains ON and the boiler continues to cycle, 5 mins off, 5 mins on.
My understanding was that the programmer feeds the power to the rest of
the system, so how did the pump continue ? Could this be a short
circuit? How did the boiler contine - is it on the same circuit as the
pump?

OK. Perhaps we should really have started with the boiler.

Either the boiler has just line,neutral & earth connnections and the pump
is in parallel with it.
Or the boiler has Line, Switch Line, Neutral & earth in which case it the
boiler will control the pump or the pump is in parallel with the switched
live.

Trace back from the boiler to find out why it is getting a demand signal.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Alex DV wrote:
1) Is there a large variation between the on click and off click?
No.

2) If you set the heating on and then turn the thermostat down till it
nearly clicks off - what happens then?
Boiler stays on until stat reaches stat's temp.

Ok, so after some days of investigations, I have more information.

I tried disconnecting the room stat, the programmer and the tank stat
(removing the L and N wire in each case). The result is that the pump
remains ON and the boiler continues to cycle, 5 mins off, 5 mins on.
My understanding was that the programmer feeds the power to the rest of
the system, so how did the pump continue ? Could this be a short
circuit? How did the boiler contine - is it on the same circuit as the
pump?


Sounds like you have a stuck motorized valve.

The way it goes in my system is

overall switched fused spur feeds timer.

Timer feeds overall 'stats.

Overall 'stats feed motorized valves..

....these have switches in them that feed the boiler/pump.

Boilers own internal stats switches it on and off (but leaves pump
running anyway) to circulate hot water, but not TOO hot water :-).

One of mine stuck ON..the motorized bit seized up. Fortunately I was
able to replace just the motor and gear and switch assembly. No plumbing
required.

In an earlier contribution to this discussion,
Alex DV wrote:

1) Is there a large variation between the on click and off click?
No.

2) If you set the heating on and then turn the thermostat down till it
nearly clicks off - what happens then?
Boiler stays on until stat reaches stat's temp.

Ok, so after some days of investigations, I have more information.

I tried disconnecting the room stat, the programmer and the tank stat
(removing the L and N wire in each case). The result is that the pump
remains ON and the boiler continues to cycle, 5 mins off, 5 mins on.
My understanding was that the programmer feeds the power to the rest
of the system, so how did the pump continue ? Could this be a short
circuit? How did the boiler contine - is it on the same circuit as
the pump?

Can you remind us how many motorised valves you have, and what type it/they
are (2-port or 3-port)? If you have more than one 2-port valves, it is
likely that you have an S-plan system.

The way in which this works is that the programmer and room/tank thermostats
purely control the valves. The valves have auxilliary contacts which close
when the valve opens - and it is these contacts which control the boiler and
pump. So if a valve is stuck open, the boiler and pump will operate
regardless of what the programmer and stats are doing.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but not regularly monitored.

There is only 1 3-way valve.

When I switch the programmer to HW on (CH off), the valve correctly
"turns" to "Hot Water". When I switch the programmer to CH on (HW off)
the programmer once again turns correctly to "Central Heating". When I
switch the programmer completely off (CH off, HW off), the valve stays
on whichever was the last position it was pointing to. Then the bolier
cycling behaviour starts, which either heats the radiators (if valve
points to CH), or heats the hot water tank (if valve points to HW).
Whatever the position of the valve, and whatever the setting on the
programmer (including fully off), the pump stays on.

Alex.

In an earlier contribution to this discussion,
Alex DV wrote:

There is only 1 3-way valve.

When I switch the programmer to HW on (CH off), the valve correctly
"turns" to "Hot Water". When I switch the programmer to CH on (HW
off) the programmer once again turns correctly to "Central Heating".
When I switch the programmer completely off (CH off, HW off), the
valve stays on whichever was the last position it was pointing to.
Then the bolier cycling behaviour starts, which either heats the
radiators (if valve points to CH), or heats the hot water tank (if
valve points to HW). Whatever the position of the valve, and whatever
the setting on the programmer (including fully off), the pump stays
on.

Alex.

OK, so you can forget what I said about S-Plan - 'cos you've got a Y-Plan
system.

Remind me again. Was it all working ok - and suddenly started doing this
without anything having been touched/changed?

The only other possible explanation I can offer is this:

Assuming that the boiler controls the pump, in order to provide pump
over-run, the boiler will have a permanent live and a switched live wire
connected to it. The permanent live is - like it says - live all the time
regardless of what the programmer, thermostat and valve are doing. The
switched live is controlled by the programmer and/or valve (depending on
mode) and should only be live when there's a demand for heat.

It seems to me that the switched live has somehow got itself connected to
the permanent live - maybe a short somewhere or a component failure. This
could be in the external wiring or within the boiler itself.

So you need to identify the switched live wire, and disconnect it from the
boiler. If the boiler and pump *still* run, the fault has to be inside the
boiler. If it doesn't, it's an external problem - and you need to find out
why this wire is live when it shouldn't be.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but not regularly monitored.

On 31 Mar 2006 06:43:32 -0800, "Alex DV"
wrote:

There is only 1 3-way valve.

When I switch the programmer to HW on (CH off), the valve correctly
"turns" to "Hot Water". When I switch the programmer to CH on (HW off)
the programmer once again turns correctly to "Central Heating". When I
switch the programmer completely off (CH off, HW off), the valve stays
on whichever was the last position it was pointing to. Then the bolier
cycling behaviour starts, which either heats the radiators (if valve
points to CH), or heats the hot water tank (if valve points to HW).
Whatever the position of the valve, and whatever the setting on the
programmer (including fully off), the pump stays on.

Alex.
Try disconecting the "demand wire " from the boiler. If the boiler
still runs there is a fault (short) in the boiler. Otherwise replace
demand and disconect demand from the valve at the junction box if
boiler is still running then short is in the cable so replace that.
Otherwise from what you said ie "removed all stats and timers and
still runs" then its the valve head.

Alex DV wrote:
There is only 1 3-way valve.

When I switch the programmer to HW on (CH off), the valve correctly
"turns" to "Hot Water". When I switch the programmer to CH on (HW off)
the programmer once again turns correctly to "Central Heating". When I
switch the programmer completely off (CH off, HW off), the valve stays
on whichever was the last position it was pointing to. Then the bolier
cycling behaviour starts, which either heats the radiators (if valve
points to CH), or heats the hot water tank (if valve points to HW).
Whatever the position of the valve, and whatever the setting on the
programmer (including fully off), the pump stays on.

Alex.

I am not familiiar with 3-way valves, but shouldn't it return to 'all
off' when no demand is called for?

In an earlier contribution to this discussion,
The Natural Philosopher wrote:

Alex DV wrote:
There is only 1 3-way valve.

When I switch the programmer to HW on (CH off), the valve correctly
"turns" to "Hot Water". When I switch the programmer to CH on (HW
off) the programmer once again turns correctly to "Central Heating".
When I switch the programmer completely off (CH off, HW off), the
valve stays on whichever was the last position it was pointing to. Then
the bolier cycling behaviour starts, which either heats the
radiators (if valve points to CH), or heats the hot water tank (if
valve points to HW). Whatever the position of the valve, and
whatever the setting on the programmer (including fully off), the
pump stays on. Alex.

I am not familiiar with 3-way valves, but shouldn't it return to 'all
off' when no demand is called for?

I nearly posted along similar lines - and then I remembered that Y-Plan
systems have to have a HW-off signal - so there'll always be one live wire
going to the valve even when the programmer and stats are off. Whether there
is a mode of failure (like a shorted out micro-switch) which could bring the
boiler and pump on under these circumstances, I'm not sure.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but not regularly monitored.

Update: Fixed!

I finally had the boiler fixed. In the end I had to concede, it got
the better of me, so I got a local plumber to look at it. It turned
out to be a faulty "pump overrun stat" within the boiler itself. A
replacement stat has fixed the problem. Many thanks to all posters.

Alex.