I have a gas boiler that provides the heat for radiators and water. I
have an electronic timer that allows me to set two on and off times each
day. The boiler will run at those times if required and I can select
"off", "auto", "once" or "on" for heating and water separately.

My normal summer setting is "off" for heating and "auto" for hot water.

In the last week, I have noticed that the radiators are heating up when
the boiler is running, even though the controller is set to "off" for
heating.

I have no room thermostat, but each radiator has a thermostatic valve,
so I can turn them all off, but that isn't really the point. I want to
get things running smoothly before the winter comes.

I had the boiler serviced two weeks ago, but he just hoovered the boiler
out, checked gas pressures etc., so I can't see how he could have caused
this problem.

The only other components of the system that I can see are one motorised
valve (I'm not sure if that controls the water or the heating), and a
pump - presumably for the heating.

Can anybody suggest where the problem might be and whether I need to
call in professional help to fix it. I can do basic electrics and
plumbing, but I've never drained down a central heating system.

TIA

Steve

The only other components of the system that I can see are one motorised
valve (I'm not sure if that controls the water or the heating), and a
pump - presumably for the heating.

The most common arrangement when you have fully independent control is a 3
way valve to choose heating, hot water or both and a pump that pumps both
water and heating. However, you do sometimes get arrangements such as having
a gravity loop on water controlled by a zone valve, whilst having the
heating controlled by the pump.

Looking at the zone valve, does it have 3 pipes coming out of it, or 2? We
need to identify if you have S-plan (unlikely unless you've missed a zone
valve), Y-plan, C-plan or some other control arrangement.

Your modifications/repairs should include ensuring that you have either a
room thermostat or a flow switch that turns off the boiler when the flow
through the radiators drops down low.

Also ensure that you have a cylinder thermostat that does the same for the
hot water.

Christian.

In an earlier contribution to this discussion,
Steve wrote:

I have a gas boiler that provides the heat for radiators and water. I
have an electronic timer that allows me to set two on and off times
each day. The boiler will run at those times if required and I can
select "off", "auto", "once" or "on" for heating and water separately.

My normal summer setting is "off" for heating and "auto" for hot
water.
In the last week, I have noticed that the radiators are heating up
when the boiler is running, even though the controller is set to
"off" for heating.

I have no room thermostat, but each radiator has a thermostatic valve,
so I can turn them all off, but that isn't really the point. I want
to get things running smoothly before the winter comes.

I had the boiler serviced two weeks ago, but he just hoovered the
boiler out, checked gas pressures etc., so I can't see how he could
have caused this problem.

The only other components of the system that I can see are one
motorised valve (I'm not sure if that controls the water or the
heating), and a pump - presumably for the heating.

Can anybody suggest where the problem might be and whether I need to
call in professional help to fix it. I can do basic electrics and
plumbing, but I've never drained down a central heating system.

TIA

Steve

Did the problem start when the boiler was serviced? Even if no other parts
were touched, the system could have been tested after the service and - if
you have a 'sticky' zone valve - that could have jammed in the mid position.

I am assuming at the moment that you have a Y-Plan system - which is fully
pumped, with a 3-port valve to direct water either to the heating coil in
the HW cylinder or to the radiators or to both at the same time. The valve
has a small motor to move it to the mid (both) and CH positions, and a
spring to return it to the HW position. Sometimes, if the 'wet' part of the
valve gets a bit stiff to turn (particularly in the summer, when it doesn't
get any exercise) the spring is insufficient to move it back - and it sticks
in the mid position so that whenever the HW is on, the radiators get hot
too.

Many - but not all - 3-port valves allow you to remove the electrical bit
(actuator) from the wet bit by undoing a couple of screws. If yours is like
this, remove the actuator and check how easy it is to rotate the shaft of
the valve. You should be able to move it by gripping it with your finger
and thumb - or certainly by using *light* pressure from a pair of pliers.
[It only moves through 90 degrees, with the mid-position being at 45
degrees.] If it is very stiff to turn, you may be able to free it by
gripping with pliers and moving it back and forth. If not, the wet part of
the valve will need to be replaced - which involves a partial drain-down.

While the actuator is off - but still connected electrically - you can test
it by selecting all permutations of HW and CH at the programmer/thermostats
and check that the actuator moves to the expected position in each case.

If your system isn't like this, we'll need to think again. In that case,
answer the questions posed by Christian about the number and type of valves
etc.
--
Cheers,
Roger
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Thanks to all for the info so far.

I've had a closer look and there are 3 pipes going in to the zone valve.

I assume one comes from the boiler, one goes to the HW cylinder (which
does have a cylinder thermostat) and one goes to the pump. There is a
smaller pipe that comes back from lower level on the cylinder and joins
the pipe going to the pump.

The electrical box on top of the zone valve only has one screw on it -
high up on the opposite end to where the cable goes in and the little
lever sticks out. I haven't tried unscrewing it yet - is this wise with
the power still on? It doesn't look like this screw would release the
electrical gubbins from the valve, but I suppose it might give access to
screws that do.

I have fiddled with the little lever that sticks out. It was in the
central position, but if I move it to one side or the other, it seems
content to stay where I move it to.

I have also tried putting the lever to the central position, then
switching on just the heating - the lever doesn't move. Same thing if I
try putting on just the water.

Does any of this give a clearer idea of exactly where the problem lies?

In an earlier contribution to this discussion,
Steve wrote:

Thanks to all for the info so far.

I've had a closer look and there are 3 pipes going in to the zone
valve.
I assume one comes from the boiler, one goes to the HW cylinder (which
does have a cylinder thermostat) and one goes to the pump. There is a
smaller pipe that comes back from lower level on the cylinder and
joins the pipe going to the pump.

Is there any chance that you could take a photo of the pipework round the
3-port valve and pump - and stick it somewhere on the net, and post a link
to it here?


The electrical box on top of the zone valve only has one screw on it -
high up on the opposite end to where the cable goes in and the little
lever sticks out. I haven't tried unscrewing it yet - is this wise
with the power still on? It doesn't look like this screw would
release the electrical gubbins from the valve, but I suppose it might
give access to screws that do.


Is there any make/model information on the actuator? If you tell us that,
someone may be familiar with your type of valve.


I have fiddled with the little lever that sticks out. It was in the
central position, but if I move it to one side or the other, it seems
content to stay where I move it to.

I have also tried putting the lever to the central position, then
switching on just the heating - the lever doesn't move. Same thing
if I try putting on just the water.

Does any of this give a clearer idea of exactly where the problem
lies?

If the valve is working, it should certainly move when you change heating
selections. It's a very low geared motor though - and may take a minute or
more to move from one position to another. Are you giving it long enough?

From what you've written so far, the prime suspect is still the 3-port
valve.

One more thing you can try. Remove *all* power from the system by turning it
off at the main FCU - not just at the programmer. You should then see and
hear the valve move to the HW position under the action of the spring
return. If it doesn't, something is definitely wrong with the valve. If it
does, try running the system again - it may just be ok this time. These
valves do sometimes get confused, and need to be "re-booted".
--
Cheers,
Roger
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here are some photos that might make things clearer

pipework
http://i86.photobucket.com/albums/k8...pipelayout.jpg

one end of electrical bit
http://i86.photobucket.com/albums/k8...ann/oneend.jpg

other end of electrical bit
http://i86.photobucket.com/albums/k8...n/otherend.jpg

Having now had a closer look, its a Honeywell 9123. Info on the "other
end" gives a part number for head replacement - is that likely to mean
that the electrical bit is removable?

I have tried "rebooting" but nothing moved. On closer inspection, the
lever slot is marked Auto on the left and Manual On on the right.

I have now found one combination of lever position and on/off settings
where the lever does move under its own steam - If I push the lever to
the right, then put Water ON while heating is OFF, the lever moves back
to the centre position


Thanks for taking the time to help me to understand this

Steve

In an earlier contribution to this discussion,
Steve wrote:

here are some photos that might make things clearer

pipework
http://i86.photobucket.com/albums/k8...pipelayout.jpg

one end of electrical bit
http://i86.photobucket.com/albums/k8...ann/oneend.jpg

other end of electrical bit
http://i86.photobucket.com/albums/k8...n/otherend.jpg

Having now had a closer look, its a Honeywell 9123. Info on the
"other end" gives a part number for head replacement - is that likely
to mean that the electrical bit is removable?

I have tried "rebooting" but nothing moved. On closer inspection, the
lever slot is marked Auto on the left and Manual On on the right.

I have now found one combination of lever position and on/off settings
where the lever does move under its own steam - If I push the lever to
the right, then put Water ON while heating is OFF, the lever moves
back to the centre position


Thanks for taking the time to help me to understand this

Steve

Nice photos! It's a fairly conventional fully pumped Y-Plan system, but I
think you mis-described it a bit in an earlier post.

Water comes from the boiler, through the pump, and up to the central inlet
of the 3-port valve. The LH outlet goes to the radiators. The RH outlet goes
to the cylinder coil. The bottom water pipe (not the gas pipe) comes back
from the coil and returns to the boiler. It is probably joined by the CH
return under the floorboards. The small pipe with the gate valve on it is a
by-pass so that if the heating is on but all the radiator TRVs are closed,
the water still has somewhere to go.

The fact that a part number is quoted for replacing the head almost
certainly means that the actuator can be detached. Maybe there are screws
going up into the bottom of it, through the brass flange on the top of the
wet bit of the valve?

Are you absolutely sure that the valve isn't returning to the HW position?
When it does, it requires pressure on the lever to move it elsewhere. when
it is in the mid or CH position, the lever flaps about without doing
anything. Note that in the manual position, the lever only moves the valve
to the mid position. There is no way of moving it manually to the CH
position.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Nice photos! It's a fairly conventional fully pumped Y-Plan system, but I
think you mis-described it a bit in an earlier post.
Sorry I confused things before - my ignorance knows no bounds on this
sort of thing. I thought the water was flowing in the opposite direction

Water comes from the boiler, through the pump, and up to the central inlet
of the 3-port valve. The LH outlet goes to the radiators. The RH outlet goes
to the cylinder coil. The bottom water pipe (not the gas pipe) comes back
from the coil and returns to the boiler. It is probably joined by the CH
return under the floorboards. The small pipe with the gate valve on it is a
by-pass so that if the heating is on but all the radiator TRVs are closed,
the water still has somewhere to go.

The fact that a part number is quoted for replacing the head almost
certainly means that the actuator can be detached. Maybe there are screws
going up into the bottom of it, through the brass flange on the top of the
wet bit of the valve?
Emboldened by your advice, I removed the cover from the actuator and
inside the casing I found two screws connecting it to the brass flange.
I removed them (carefully, as the thing was still electrically
connected) and tried to lift the actuator off of the brass bit. It
didn't want to come off - it wiggled about a bit but would not come
clear. Then there was a ping, like a spring jumping out of place and I
decided to put it back together and seek more advice. As far as I can
see, the spring is still in place.


Are you absolutely sure that the valve isn't returning to the HW position?
When it does, it requires pressure on the lever to move it elsewhere. when
it is in the mid or CH position, the lever flaps about without doing
anything. Note that in the manual position, the lever only moves the valve
to the mid position. There is no way of moving it manually to the CH
position.


I have checked again and the only situation where the lever moves of its
own accord is when I push the lever to the right (Manual), then put
Water ON while heating is OFF. This causes the lever to move back to
the centre position.

Something else that struck me as odd is that when I stopped fiddling
with this earlier this morning, I left the lever pushed over to the
left( Auto). When I went to test all this just now,some 7 hours later,
the lever was still on the left but the actuator was hot to the touch,
even though neither water or heating had been on for about 7 hours and
all of the surrounding pipes were stone cold. When I had the casing off
of the actuator, the heat was coming from the silver coloured drum
shaped object - presumably the motor.

Is this making any sense yet?

I was expecting this to be a Honeywell 4073 mid position valve before I
saw your photo. It still 'looks' like one but clearly isn't.

Generally, the motorised valves with a replaceable actuator have a
dimple on the top of the casing. it is not clear from yours whether you
have this or not.

Anyway, the problem is one of two things; mechanical or electrical. In
order to diagnose the fault you will need a multimeter and will have to
poke around in the wiring centre. An electrical neon screwdriver will
not be sufficient to do this.

Are you confident of not electrocuting yourself?

When I had the casing off of the actuator, the heat was coming
from the silver coloured drum shaped object - presumably the motor.

It sounds like the head is totally knackered. Persist with removing the
thing. Any springs are part of the head and it is of no relevence if they
are damaged or lost.

Once the head is off, make sure the spindle turns relatively easily. If so,
you can probably just put a new head on it. You might even get away with
replacing just the motor bit. It is called a "synchron motor" and is easy to
source if you don't mind a little soldering.

Christian.

wrote:
I was expecting this to be a Honeywell 4073 mid position valve before I
saw your photo. It still 'looks' like one but clearly isn't.
It is getting on for 15 years old - might it be an earlier model?


Generally, the motorised valves with a replaceable actuator have a
dimple on the top of the casing. it is not clear from yours whether you
have this or not.

There is a dimple on the top of the casing, just above the out of focus
screw you can almost see at the top centre of the "other end" photo -
with that, and the info about head replacement on the casing, I hope I
am safe in assuming that it can be replaced. Still need to figure out
if that's what needs replacing though. Are we talking about a lot of
money here?

Anyway, the problem is one of two things; mechanical or electrical. In
order to diagnose the fault you will need a multimeter and will have to
poke around in the wiring centre. An electrical neon screwdriver will
not be sufficient to do this.

Are you confident of not electrocuting yourself?

I am never confident around live electrics - that may be why I have
avoided electrocution so far. The trouble is I don't have a multimeter
and I almost certainly wouldn't know how to use one.

Christian McArdle wrote:
When I had the casing off of the actuator, the heat was coming
from the silver coloured drum shaped object - presumably the motor.


I have since left the lever in the central position and the motor has
cooled down.

It sounds like the head is totally knackered. Persist with removing the
thing. Any springs are part of the head and it is of no relevence if they
are damaged or lost.
If I do this, can I safely continue to use the system for water heating
until I can find a replacement?


Once the head is off, make sure the spindle turns relatively easily. If so,
you can probably just put a new head on it. You might even get away with
replacing just the motor bit. It is called a "synchron motor" and is easy to
source if you don't mind a little soldering.
It's 15 years old, so I think I'd probably be happier renewing the whole
actuator.

Am I right in thinking that a plumbers merchant is the place to go for
this sort of thing?


Christian.

Steve wrote:
Christian McArdle wrote:
When I had the casing off of the actuator, the heat was coming
from the silver coloured drum shaped object - presumably the motor.


I have since left the lever in the central position and the motor has
cooled down.

It sounds like the head is totally knackered. Persist with removing the
thing. Any springs are part of the head and it is of no relevence if they
are damaged or lost.
If I do this, can I safely continue to use the system for water heating
until I can find a replacement?


Once the head is off, make sure the spindle turns relatively easily.
If so,
you can probably just put a new head on it. You might even get away with
replacing just the motor bit. It is called a "synchron motor" and is
easy to
source if you don't mind a little soldering.
It's 15 years old, so I think I'd probably be happier renewing the whole
actuator.

However that means draining down the pipework.

What happened to one of my 20ways was that the motor got tired somehow,
and the valve got stiff.

Removing the head allowed me to wiggle the valve, and a new head cured
all other problems.


Am I right in thinking that a plumbers merchant is the place to go for
this sort of thing?


Yes. Take copious photos, try and get the head off and work teh valve
manually. It its reasonably free, disconnect electrics and take head in.

ISTR I got a new head online somewhere tho.


Christian.

Thanks to the advice given here, I persevered and got the actuator off.
I tried to turn the spindle on the brass valve, but it won't turn it
with my fingers, or even with medium pressure with pliers.

I take it that this means the brass bit needs replacing. That is not
good news - I have never drained down a system and I don't even know
where the drain cock is for this one.

I had found a replacement actuator on the net, but I'm not sure now if I
need one - when I run the heating with the actuator off, it clicks
throgh 90 degrees, switches off, then a few seconds later does the same
again. Does that mean it's OK?

Even if it is OK, I haven't been able to find the right brass bit to go
with the existing actuator so presumably that means I'll have to get a
complete new assembly.

This raises so many questions for me - must it be honeywell like the
junction box it connects to?, must it be a particular type?, what size
does it need to be?, will the wiring requirements of a different valve
exactly match those of the old one?, where is the draincock?, do I have
to drain the whole system?, etc. etc.

This may be blasphemy to this group, but I'm beginning to think I might
be better getting a professional in to tackle this. What do you think?

Even if I do sell out and call in a pro, I'd like to thank everyone for
the excellent advice and support - it's improved my understanding of how
all that stuff works no end,

Steve

This raises so many questions for me - must it be honeywell like the
junction box it connects to?, must it be a particular type?, what size
does it need to be?, will the wiring requirements of a different valve
exactly match those of the old one?, where is the draincock?, do I have
to drain the whole system?, etc. etc.

If you are replacing the entire valve, the main compatibility issue is that
the connections are at exactly the same place and the thread (either fine or
medium) matches the original nuts. If so, no pipework modification or olive
removal is required.

The other main issue is making sure it is the same type of valve (i.e. mid
position, diverter etc).

However, you might as well replace with another Honeywell. They are well
regarded and not that much extra in cost.

Christian.

Steve wrote:
Thanks to the advice given here, I persevered and got the actuator off.
I tried to turn the spindle on the brass valve, but it won't turn it
with my fingers, or even with medium pressure with pliers.

Oh bugger..

I take it that this means the brass bit needs replacing. That is not
good news - I have never drained down a system and I don't even know
where the drain cock is for this one.

I had found a replacement actuator on the net, but I'm not sure now if I
need one - when I run the heating with the actuator off, it clicks
throgh 90 degrees, switches off, then a few seconds later does the same
again. Does that mean it's OK?

Possibly. Howver as you point out..


Even if it is OK, I haven't been able to find the right brass bit to go
with the existing actuator so presumably that means I'll have to get a
complete new assembly.

Almost certainly

This raises so many questions for me - must it be honeywell like the
junction box it connects to?, must it be a particular type?, what size
does it need to be?, will the wiring requirements of a different valve
exactly match those of the old one?, where is the draincock?, do I have
to drain the whole system?, etc. etc.

These things are fairly standard, but, yes, you may need to mod the
pipework slightly for a new one.

This may be blasphemy to this group, but I'm beginning to think I might
be better getting a professional in to tackle this. What do you think?


I think you are probably right. Its a days work for a competenet plumber
(if you can find one) but if you get in a muddle it might leave you with
water on the floor or a non functional heating system for several days..

e Even if I do sell out and call in a pro, I'd like to thank everyone for
the excellent advice and support - it's improved my understanding of how
all that stuff works no end,

Steve