As discussed previously I suspect I have a fault in the 3 port valve.
Drayton Mid Position Actuator MA1.

For diagnostics, do I have to do more that check that when CH is called
for by the programmer power goes to the thermostat, and when the
thermostat clicks on power comes back to the valve?

I am assuming that the sequence at the valve is:

(1) CH request from the thermostat

(2) Mid port valve moves to open CH port

(3) Controller then calls for pump and boiler

This has the second assumption that if (2) fails to happen then (3) will
not happen (which seems to be more or less what is happening).

Diagnostics day tomorrow, hopefully.


Cheers


Dave R


--
Dell XPS laptop running W8.1

David wrote in news:g8rj75Fh0nmU2
@mid.individual.net:

As discussed previously I suspect I have a fault in the 3 port valve.
Drayton Mid Position Actuator MA1.

For diagnostics, do I have to do more that check that when CH is called
for by the programmer power goes to the thermostat, and when the
thermostat clicks on power comes back to the valve?

I am assuming that the sequence at the valve is:

(1) CH request from the thermostat

(2) Mid port valve moves to open CH port

(3) Controller then calls for pump and boiler

This has the second assumption that if (2) fails to happen then (3) will
not happen (which seems to be more or less what is happening).

Diagnostics day tomorrow, hopefully.


Cheers


Dave R



The call for the pump and boiler comes from the switches in the valve as
far as I know.

It happens that DerbyBorn formulated :
The call for the pump and boiler comes from the switches in the valve as
far as I know.

Correct!

Timeclock feeds to stat, stat feeds through to valve actuator, when
valve actuator has set itself to the correct position, its micro
switches then feeds through to the boiler and pump. On more modern
systems, it just feeds through to the boiler alone and the boiler then
turns the pump on, that allows the boiler to run the pump beyond the
time the boiler is firing, to remove heat from the boilers heat
exchanger.

So if the valve actuator fails to achieve it required position, the
boiler will not fire. Sticking actuators, especially the spring return
type are a common fault.

On 30 Dec 2018 09:59:01 GMT, David wrote:

As discussed previously I suspect I have a fault in the 3 port valve.
Drayton Mid Position Actuator MA1.

For diagnostics, do I have to do more that check that when CH is called
for by the programmer power goes to the thermostat, and when the
thermostat clicks on power comes back to the valve?

I am assuming that the sequence at the valve is:

(1) CH request from the thermostat

(2) Mid port valve moves to open CH port

(3) Controller then calls for pump and boiler

This has the second assumption that if (2) fails to happen then (3) will
not happen (which seems to be more or less what is happening).

Diagnostics day tomorrow, hopefully.


Cheers


Dave R
Circuit diagram here if it helps:
https://www.draytoncontrols.co.uk/si....%2022mm_0.pdf
also this may help:
https://www.diynot.com/diy/threads/d...-valve.352427/

On Sun, 30 Dec 2018 11:14:26 +0000, Harry Bloomfield wrote:

It happens that DerbyBorn formulated :
The call for the pump and boiler comes from the switches in the valve
as far as I know.

Correct!

Timeclock feeds to stat, stat feeds through to valve actuator, when
valve actuator has set itself to the correct position, its micro
switches then feeds through to the boiler and pump. On more modern
systems, it just feeds through to the boiler alone and the boiler then
turns the pump on, that allows the boiler to run the pump beyond the
time the boiler is firing, to remove heat from the boilers heat
exchanger.

So if the valve actuator fails to achieve it required position, the
boiler will not fire. Sticking actuators, especially the spring return
type are a common fault.

Thanks, people.

This seems to be the most likely fault.

Cheers


Dave R

--
Dell XPS laptop running W8.1

On Sun, 30 Dec 2018 09:59:01 +0000, David wrote:

As discussed previously I suspect I have a fault in the 3 port valve.
Drayton Mid Position Actuator MA1.

For diagnostics, do I have to do more that check that when CH is called
for by the programmer power goes to the thermostat, and when the
thermostat clicks on power comes back to the valve?

I am assuming that the sequence at the valve is:

(1) CH request from the thermostat

(2) Mid port valve moves to open CH port

(3) Controller then calls for pump and boiler

This has the second assumption that if (2) fails to happen then (3) will
not happen (which seems to be more or less what is happening).

Diagnostics day tomorrow, hopefully.

O.K.
Further help required, please.

First a view of the wiring in the wiring box.
http://wiki.diyfaq.org.uk/index.php/File:Central_Heating_wiring.JPG

Next a view of the wiring instructions inside the lid.
http://wiki.diyfaq.org.uk/index.php/File:CH_wiring_diagram.jpg

Finally the wiring diagram from Drayton.
https://www.draytoncontrols.co.uk/sites/default/files/IG.%2022mm_0.pdf

When the power is on, the programmer has CH turned on and the thermostat
is calling for heat then there should be current flowing to/from the white
wire in the PDF.

Looking at the PDF it seems as though the common terminal is live and the
calling terminal is neutral. I assume with 240V AC this is largely
irrelevant for basic diagnostic purposes.

So for testing purposes, working from the table inside the lid of the
wiring loom, there should be power between COM and CALL (2 and 3) and 2
should be linked to 4 which should then pass power to the white wire from
the Mid Port Switch.

Or is it?

This is where I get horribly confused because in my first round of testing
it seems that if I have power and the programmer calling for CH but the
thermostat turned right down, I get 240V between 2 & 3 and 2 & 4.
If I have the same with the thermostat turned right up then I get 0V
between 3 and both 2 & 4.

This is the opposite of what I was expecting.

Regardless, with 240V or no 240V between 3&4 the pump doesn't run and the
boiler doesn't fire.

However to proceed with the diagnostics I need to know that my first step
is correct.

I think my next step will be to take the thermostat off the wall and check
the wiring there. There should (according to the PDF) be live and neutral
into the thermostat (but why?) and a third wire to carry the call for heat.

This does seem to be reasonable, because if the programmer is calling for
heat then you can hear the thermostat click on and off, but if the
programmer isn't calling for CH the thermostat doesn't click.

Any advice most welcome.

I keep adding to this. Would a valid test be to disconnect the white wire
from 4 so that I'm only testing the thermostat output assuming 3/COM is
the live feed?


Cheers


Dave R

--
Dell XPS laptop running W8.1

On Mon, 31 Dec 2018 15:55:26 +0000, David wrote:

snip

Addendum:
http://wiki.diyfaq.org.uk/index.php/File:Wiring_Links.jpg
Links on the back of the wiring block.

Looks to be a link between 3 and 9 which is puzzling me.

Cheers


Dave R


--
Dell XPS laptop running W8.1

On 31/12/2018 16:17, David wrote:
On Mon, 31 Dec 2018 15:55:26 +0000, David wrote:

snip

Addendum:
http://wiki.diyfaq.org.uk/index.php/File:Wiring_Links.jpg
Links on the back of the wiring block.

Looks to be a link between 3 and 9 which is puzzling me.

Cheers


Dave R



Can you remind us whether this has *ever* worked properly. If it hasn't,
it's most likely that it's wired incorrectly. If it *has*, it has
presumably developed a fault - most likely associated with the 3-port valve.

The only wiring diagram you should need is this one:
http://wiki.diyfaq.org.uk/index.php?...lan-Wiring.gif

Clearly your connection box doesn't use the same numbered terminals for
the same things, so you will need to work out the equivalence. In order
to design any diagnostics, it's important to understand how a Y-Plan
system works and, in particular, the part played by the 3-port valve.

There are two electrical inputs to the valve actuator - white (heating
demand) and grey (hot water off or satisfied) - and one output (orange -
switched on by the valve in the heating-only state).

When there is a HW demand but no CH demand, the valve is unpowered and
its spring return holds it in the HW position. The boiler (and pump if
the two are connected together as shown)[1] is powered from (1) on the
cylinder stat. The white and grey wires will be at 0v but the orange
wire will be at 240v even though it's not being switched by the valve,
because it's connected to the boiler.

If you now add a CH demand, the white wire will be at 240v, and will
cause the valve to motor to the mid position. The boiler and pump will
still be powered from (1) on the cylinder stat.

If you now remove the HW demand, so that there is only a CH demand, the
grey wire will go to 240v. [This assumes that there is a HW-off
connection on the programmer and that the cylinder stat has change-over
contacts, as shown - without which the system won't work]. This causes
the valve to motor to the CH position, at which point a micro-switch is
operated which switches live from white or grey (can't remember which)
to orange. The boiler is no longer powered from (1) on the cylinder stat
but is powered by the orange wire instead. Clearly, if that micro-switch
doesn't do its job, there will be no power to the boiler and pump.

Y-Plan systems can be difficult to diagnose because connections which
you don't expect to be live often are because they're connected to
something else which is live (e.g. the orange wire) or through induction
or the internal workings of the valve actuator.

I've known actuators simply getting 'confused' - requiring the system to
be completely powered down, after which they work ok again - but I guess
you've tried that.

I had lots of problems with my system when it was configured as a
Y-Plan. In the end, I bit the bullet and converted it to S-Plan -
replacing the 3-port valve with two 2-port valves - and have never
looked back.

[1] If your system requires pump over-run, the pump may be connected to
dedicated terminals on the boiler, and not simply wired in parallel with it.
--
Cheers,
Roger
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On Mon, 31 Dec 2018 20:30:16 +0000, Roger Mills wrote:

On 31/12/2018 16:17, David wrote:
On Mon, 31 Dec 2018 15:55:26 +0000, David wrote:

snip

Addendum: http://wiki.diyfaq.org.uk/index.php/File:Wiring_Links.jpg
Links on the back of the wiring block.

Looks to be a link between 3 and 9 which is puzzling me.

Cheers


Dave R



Can you remind us whether this has *ever* worked properly. If it hasn't,
it's most likely that it's wired incorrectly. If it *has*, it has
presumably developed a fault - most likely associated with the 3-port
valve.
snip

I can't honestly say if it has ever worked as designed - it is not my
house.

I have a suspicion that it may have been faulty for a long time because
when the hot water is on via the programmer, the CH is on via the
programmer, and there is a call for heat from the HW thermostat then the
valve is (usually) in the mid position and the radiators heat up.

It is only because the house started from very cold and took an unusually
long time to heat up that I started to investigate, first by feeling all
the radiators (which need balancing but not a major problem) and noting
that they weren't heating up consistently when the programmer and
thermostat were calling for heating.

I suspect that the owner thought that the heating wasn't very good but
couldn't be arsed to get someone to investigate in detail.

If you are in constant occupation and use a significant amount of hot
water every day then the house stays warm.

Anyway, I'm going to replace the 3 port valve head (wish me luck) and see
if that does the trick.

I am not enthused to undertake a full diagnosis of the wiring - I would if
it was my own system but this is a house which is a long way away from my
home and needs to be left empty but frost free over the winter.

I would just leave it with the heating and hot water programmed, but every
now and then the 3 way valve moves to the HW only position and doesn't
seem to move back. I am assuming that either the valve head is confused/
faulty or it is seeing a call for HW but no call for CH. Which is again a
puzzle because AFAIK this can happen when the CH is calling for heat.

Oh, and thank you for your comprehensive explanation; just one thing,
though; I thought when there was no call for HW or CH the valve, unpowered,
returned to the mid position. To go HW only or CH only required power to
move the valve to close off the other feed. But I may well be wrong.

Cheers


Dave R


--
Dell XPS laptop running W8.1

snip

Oh, and thank you for your comprehensive explanation; just one thing,
though; I thought when there was no call for HW or CH the valve,
unpowered,
returned to the mid position. To go HW only or CH only required power to
move the valve to close off the other feed. But I may well be wrong.

Oops!

"The valve has 3 pipe connections, in a T formation. The centre leg of the
T is the inlet and the two short arms are the outlets, usually referred to
as ports A and B. Actuation controls whether the flow from the inlet
passes to the A or B port. In the resting state flow is to the B port
(usually the hot water circuit)."


Cheers


Dave R


--
Dell XPS laptop running W8.1

On 01/01/2019 12:07, David wrote:
snip

Oh, and thank you for your comprehensive explanation; just one thing,
though; I thought when there was no call for HW or CH the valve,
unpowered,
returned to the mid position. To go HW only or CH only required power to
move the valve to close off the other feed. But I may well be wrong.

Oops!

"The valve has 3 pipe connections, in a T formation. The centre leg of the
T is the inlet and the two short arms are the outlets, usually referred to
as ports A and B. Actuation controls whether the flow from the inlet
passes to the A or B port. In the resting state flow is to the B port
(usually the hot water circuit)."


Cheers


Dave R



Correct. Although, when both demands are removed (but HW-off is still
live) the valve tends to stay in the position it was last in until a new
demand appears. That's why you have to remove ALL power in order to
re-boot it - so that it doesn't even have a HW-off signal. When you
remove the power, you can often hear it whirring back to the HW position.
--
Cheers,
Roger
____________
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checked.

On Sun, 30 Dec 2018 09:59:01 +0000, David wrote:

As discussed previously I suspect I have a fault in the 3 port valve.
Drayton Mid Position Actuator MA1.

For diagnostics, do I have to do more that check that when CH is called
for by the programmer power goes to the thermostat, and when the
thermostat clicks on power comes back to the valve?

I am assuming that the sequence at the valve is:

(1) CH request from the thermostat

(2) Mid port valve moves to open CH port

(3) Controller then calls for pump and boiler

This has the second assumption that if (2) fails to happen then (3) will
not happen (which seems to be more or less what is happening).

Diagnostics day tomorrow, hopefully.

Gave up on the diagnostics and changed the valve.

Quick and simple job of replacing wires like for like in the wiring loom.

It would have been easier if the wiring loom had been more accessible.

All now working as it should be, thank $Deity.

The original valve head has been battered for some reason; will post
pictures soon (if anyone cares).

Thanks to all for the help.


Cheers


Dave R


--
Dell XPS laptop running W8.1

On Wednesday, 2 January 2019 11:59:28 UTC, David WE Roberts (Google) wrote:

Gave up on the diagnostics and changed the valve.

Quick and simple job of replacing wires like for like in the wiring loom.

It would have been easier if the wiring loom had been more accessible.

All now working as it should be, thank $Deity.

The original valve head has been battered for some reason; will post
pictures soon (if anyone cares).

Thanks to all for the help.


Cheers


Dave R

Good. battered & fried by any chance?

On 2019-01-02 11:59:25 +0000, David said:

Gave up on the diagnostics and changed the valve.

Quick and simple job of replacing wires like for like in the wiring loom.

It would have been easier if the wiring loom had been more accessible.

All now working as it should be, thank $Deity.

The original valve head has been battered for some reason; will post
pictures soon (if anyone cares).

You mean you just swapped out the motorised valve head and not the
valve itself?

They motorised parts certainly do fail - I've had to change both the HW
and CH valve actuators last year as they were getting stuck and
buzzing. Not worth refurbing the gears or changing motors. One is a
Honeywell the other a Danfoss, installed about 15 years ago when we
moved in and redid the system.

And yes, our wiring loom is under the stairs and hard to get at...

On Wed, 02 Jan 2019 13:44:44 -0800, tabbypurr wrote:

On Wednesday, 2 January 2019 11:59:28 UTC, David WE Roberts (Google)
wrote:

Gave up on the diagnostics and changed the valve.

Quick and simple job of replacing wires like for like in the wiring
loom.

It would have been easier if the wiring loom had been more accessible.

All now working as it should be, thank $Deity.

The original valve head has been battered for some reason; will post
pictures soon (if anyone cares).

Thanks to all for the help.


Cheers


Dave R

Good. battered & fried by any chance?

Probably an apt description.

Though given the location it is difficult to work out how enough force was
applied.


Cheers


Dave R


--
Dell XPS laptop running W8.1

snip
http://wiki.diyfaq.org.uk/index.php/...lve_head_1.jpg

http://wiki.diyfaq.org.uk/index.php/File:Battered_valve_head_2.jpg

Two views of the original valve head.
It appears to have been sprung open at some point, though how and why
remains a mystery.

The clip on the back which is supposed to secure the valve head to the
valve had jumped out of its guides so the valve head was essentially free
floating.

http://wiki.diyfaq.org.uk/index.php/File:Boiler_front.jpg

Picture of the boiler front.

It has obviously had the original controls disabled and an external
controller fitted.

The boiler temperature thermostat still works but one built in timer is
missing (HW) and the other (CH) is thankfully not doing anything obvious.

Does have a sticker on the top saying that the CH and HW are now
controlled by a separate controller.

Any guesses how old this beast is?

Front panel says Gloworm 85/100.


Cheers



Dave R

--
Dell XPS laptop running W8.1

On Thursday, 3 January 2019 14:37:01 UTC, David WE Roberts (Google) wrote:


http://wiki.diyfaq.org.uk/index.php/...lve_head_1.jpg

http://wiki.diyfaq.org.uk/index.php/File:Battered_valve_head_2.jpg

Two views of the original valve head.
It appears to have been sprung open at some point, though how and why
remains a mystery.

the cable position suggests it was never put on properly

The clip on the back which is supposed to secure the valve head to the
valve had jumped out of its guides so the valve head was essentially free
floating.

http://wiki.diyfaq.org.uk/index.php/File:Boiler_front.jpg

Picture of the boiler front.

It has obviously had the original controls disabled and an external
controller fitted.

The boiler temperature thermostat still works but one built in timer is
missing (HW) and the other (CH) is thankfully not doing anything obvious.

Does have a sticker on the top saying that the CH and HW are now
controlled by a separate controller.

Any guesses how old this beast is?

Front panel says Gloworm 85/100.


Cheers



Dave R

1970s most likely, could be 80s.


NT

"Roger Mills" wrote in message
...

That's why you have to remove ALL power in order to re-boot it - so that
it doesn't even have a HW-off signal. When you remove the power, you can
often hear it whirring back to the HW position.


Why are they designed that way ? and not spring loaded back to the Heating
position
if the sync motor fails at least you would have a warm house

-

On 03/01/2019 17:50, Mark wrote:
"Roger wrote in message
...

That's why you have to remove ALL power in order to re-boot it - so that
it doesn't even have a HW-off signal. When you remove the power, you can
often hear it whirring back to the HW position.


Why are they designed that way ? and not spring loaded back to the Heating
position
if the sync motor fails at least you would have a warm house

-



History, probably. They are a development of the earlier diverter valve
- which was either HW or CH but not both at the same time. These always
defaulted to the HW position, and you didn't get any CH until the HW
demand was satisfied.

I suppose it makes sense in that you generally want HW all year round
but only want CH when it's cold. If the valve failed in the summer, you
wouldn't want CH but no HW.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Roger Mills wrote:

On 03/01/2019 17:50, Mark wrote:
"Roger wrote in message
...

That's why you have to remove ALL power in order to re-boot it - so that
it doesn't even have a HW-off signal. When you remove the power, you can
often hear it whirring back to the HW position.


Why are they designed that way ? and not spring loaded back to the Heating
position
if the sync motor fails at least you would have a warm house

-



History, probably. They are a development of the earlier diverter valve
- which was either HW or CH but not both at the same time. These always
defaulted to the HW position, and you didn't get any CH until the HW
demand was satisfied.

I suppose it makes sense in that you generally want HW all year round
but only want CH when it's cold. If the valve failed in the summer, you
wouldn't want CH but no HW.

Hmm what would pee you off more
-5c outside and snowed in with hot water but no heating
or 25c outside with no hot water but CH working

-

On 03/01/2019 23:32, Mark wrote:
Roger Mills wrote:

On 03/01/2019 17:50, Mark wrote:
"Roger wrote in message
...

That's why you have to remove ALL power in order to re-boot it - so that
it doesn't even have a HW-off signal. When you remove the power, you can
often hear it whirring back to the HW position.


Why are they designed that way ? and not spring loaded back to the Heating
position
if the sync motor fails at least you would have a warm house

-



History, probably. They are a development of the earlier diverter valve
- which was either HW or CH but not both at the same time. These always
defaulted to the HW position, and you didn't get any CH until the HW
demand was satisfied.

I suppose it makes sense in that you generally want HW all year round
but only want CH when it's cold. If the valve failed in the summer, you
wouldn't want CH but no HW.

Hmm what would pee you off more
-5c outside and snowed in with hot water but no heating
or 25c outside with no hot water but CH working

-


Well, all 3-port valves are the spawn of the devil. Far better to
convert to an S-Plan system with 2-port valves and with totally
independent control of HW and CH.
--
Cheers,
Roger
____________
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checked.