Hi,
The hot water on our elderly Glowworm boiler is scorching hot even with the
boiler thermostat set to minimum. Would the likely cause be a faulty boiler
thermocouple or thermostat, or too high gas pressure?
I'm sure that the water being too hot is making the CH pump to become very
noisy. Constant bleeding of the (newish) pump helps for a while, but
becomes noisy again several hours later. I assume both problems are
connected.
Regards
Dave

On May 21, 11:30*am, "Dave" wrote:
Hi,
The hot water on our elderly Glowworm boiler is scorching hot even with the
boiler thermostat set to minimum. *Would the likely cause be a faulty boiler
thermocouple or thermostat, or too high gas pressure?
I'm sure that the water being too hot is making the CH pump to become very
noisy. *Constant bleeding of the (newish) pump helps for a while, but
becomes noisy again several hours later. *I assume both problems are
connected.
Regards
Dave

The problem will be the primary circuit thermostat built into the
boiler. This stat is important for safe operation. The HW cylinder
stat will also be either faulty, set very high, fallen off, or never
fitted.

Thermocouple and gas pressure have nothing to do with it. Thermocouple
failure causes the gas to cut off.


NT

Thanks for such a quick reply.
Sounds like the boiler stat is the problem.
Any idea if there is an easy way to test the stat?
Regards
Dave

I think you just did! grin.
Brian

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!
"Dave" wrote in message
...
Thanks for such a quick reply.
Sounds like the boiler stat is the problem.
Any idea if there is an easy way to test the stat?
Regards
Dave

"Dave" wrote in
:

Hi,
The hot water on our elderly Glowworm boiler is scorching hot even
with the boiler thermostat set to minimum. Would the likely cause be
a faulty boiler thermocouple or thermostat, or too high gas pressure?
I'm sure that the water being too hot is making the CH pump to become
very noisy. Constant bleeding of the (newish) pump helps for a while,
but becomes noisy again several hours later. I assume both problems
are connected.
Regards
Dave



There is a fair chance that the problem is not with the boiler
but with the 2 or 3 port valve if the system is fully pumped.

What could be happening is the hot water valve is jammed in
the open position and water being heated uncontrolably when
the central heating is on.

To check, turn the boiler off for 2 or 3 hours then turn on
heating only.

After a couple of minutes feel the pipe going to to the cylinder.

If this is getting hot then look for a faulty valve or actuator.

--- Posted via news://freenews.netfront.net/ - Complaints to ---

There is a fair chance that the problem is not with the boiler
but with the 2 or 3 port valve if the system is fully pumped.

What could be happening is the hot water valve is jammed in
the open position and water being heated uncontrolably when
the central heating is on.

To check, turn the boiler off for 2 or 3 hours then turn on
heating only.

After a couple of minutes feel the pipe going to to the cylinder.

If this is getting hot then look for a faulty valve or actuator.

--- Posted via news://freenews.netfront.net/ - Complaints to
---


Hi, thanks for replying. The problem with that is that there is no 2 or 3
port valve/s.
There are only 2 x 1" copper tubes to and from the boiler to the cylinder.
There are no external stats, the system is gravity fed and the only pump is
on the feed from the boiler to the C/H.
I've been looking for another stat for the boiler but as the boiler is
around 40+ years old, parts are quite thin on the ground.
Dave

On 22/05/2012 14:46, Dave wrote:

There is a fair chance that the problem is not with the boiler
but with the 2 or 3 port valve if the system is fully pumped.

What could be happening is the hot water valve is jammed in
the open position and water being heated uncontrolably when
the central heating is on.

To check, turn the boiler off for 2 or 3 hours then turn on
heating only.

After a couple of minutes feel the pipe going to to the cylinder.

If this is getting hot then look for a faulty valve or actuator.

--- Posted via news://freenews.netfront.net/ - Complaints to
---


Hi, thanks for replying. The problem with that is that there is no 2 or 3
port valve/s.
There are only 2 x 1" copper tubes to and from the boiler to the cylinder.
There are no external stats, the system is gravity fed and the only pump is
on the feed from the boiler to the C/H.
I've been looking for another stat for the boiler but as the boiler is
around 40+ years old, parts are quite thin on the ground.
Dave


If you have any kind of 'demand' signal that still works (timer, on/off)
you could wire a new tank 'stat in series with that....

Phil wrote:
On 22/05/2012 14:46, Dave wrote:

There is a fair chance that the problem is not with the boiler
but with the 2 or 3 port valve if the system is fully pumped.

What could be happening is the hot water valve is jammed in
the open position and water being heated uncontrolably when
the central heating is on.

To check, turn the boiler off for 2 or 3 hours then turn on
heating only.

After a couple of minutes feel the pipe going to to the cylinder.

If this is getting hot then look for a faulty valve or actuator.

--- Posted via news://freenews.netfront.net/ - Complaints to
---


Hi, thanks for replying. The problem with that is that there is no
2 or 3 port valve/s.
There are only 2 x 1" copper tubes to and from the boiler to the
cylinder. There are no external stats, the system is gravity fed
and the only pump is on the feed from the boiler to the C/H.
I've been looking for another stat for the boiler but as the boiler
is around 40+ years old, parts are quite thin on the ground.
Dave


If you have any kind of 'demand' signal that still works (timer,
on/off) you could wire a new tank 'stat in series with that....

Better to change the boilers stat. You could end up with a cylinder of HW
and no CH.

--
Adam

On 22/05/2012 14:46, Dave wrote:




Hi, thanks for replying. The problem with that is that there is no 2 or 3
port valve/s.
There are only 2 x 1" copper tubes to and from the boiler to the cylinder.
There are no external stats, the system is gravity fed and the only pump is
on the feed from the boiler to the C/H.
I've been looking for another stat for the boiler but as the boiler is
around 40+ years old, parts are quite thin on the ground.
Dave

One thing is certain - the water in the cylinder *cannot* get any hotter
than that being produced by the boiler. So if it's *too* hot, the water
produced by the boiler is too hot. If this isn't reduced by turning the
boiler stat down, the boiler stat is duff!

If you can't get a replacement boiler stat, you could fit a pipe stat to
the flow pipe, and use that to interrupt the boiler demand.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

If you can't get a replacement boiler stat, you could fit a pipe stat to
the flow pipe, and use that to interrupt the boiler demand.


Excellent idea. I've got the wiring diagram and it looks a simple matter of
disconnecting the boiler stat at the control box, and wire in the new 'pipe'
stat.
Great, I'll start a.s.a.p.
Many thanks to all.
Dave

On May 21, 9:51*pm, Heliotrope Smith wrote:
"Dave" wrote :

Hi,
The hot water on our elderly Glowworm boiler is scorching hot even
with the boiler thermostat set to minimum. *Would the likely cause be
a faulty boiler thermocouple or thermostat, or too high gas pressure?
I'm sure that the water being too hot is making the CH pump to become
very noisy. *Constant bleeding of the (newish) pump helps for a while,
but becomes noisy again several hours later. *I assume both problems
are connected.
Regards
Dave

There is a fair chance that the problem is not with the boiler
but with the 2 or 3 port valve if the system is fully pumped.

*What could be happening is the hot water valve is jammed in
the open position and water being heated uncontrolably when
the central heating is on.

To check, turn the boiler off for 2 or 3 hours then turn on
heating only.

After a couple of minutes feel the pipe going to to the cylinder.

If this is getting hot then look for a faulty valve or actuator.

--- Posted via news://freenews.netfront.net/ - Complaints to ---

This cant be the cause. With boiler stat set low, the HW temp is
exceeding the setpoint of the primary, which isnt possible. Primary
circuit stat must be faulty.


NT

On May 22, 6:45*pm, "Dave" wrote:
If you can't get a replacement boiler stat, you could fit a pipe stat to
the flow pipe, and use that to interrupt the boiler demand.

Excellent idea. *I've got the wiring diagram and it looks a simple matter of
disconnecting the boiler stat at the control box, and wire in the new 'pipe'
stat.
Great, I'll start a.s.a.p.
Many thanks to all.
Dave

if it were mine I'd have a look at the existing stat contacts first,
they may be wleded together. If so, part them and file the switch
surfaces smooth with a rat's tail file. Now, doing this will have
changed its setting a fair bit, so its important to watch closely
during first run and slowly turn the stat down until it switches off
once the primary circuit water gets hot.


NT

On Tue, 22 May 2012 14:46:48 +0100, Dave wrote:

I've been looking for another stat for the boiler but as the boiler is
around 40+ years old, parts are quite thin on the ground.

So it's done it's moneys worth. Time to start looking for a
replacement I suspect that the efficiency of 40+ year old boiler
won't be very good. You could make considerable savings in gas
used... Take the opportunity to improve the control system as well
for additional savings.

Probably not G rated so the boiler scrapage scheme might not help but
a few minutes on the SEDBUK site might be worth while, though
something that old might not be listed...

--
Cheers
Dave.

if it were mine I'd have a look at the existing stat contacts first,
they may be wleded together. If so, part them and file the switch
surfaces smooth with a rat's tail file. Now, doing this will have
changed its setting a fair bit, so its important to watch closely
during first run and slowly turn the stat down until it switches off
once the primary circuit water gets hot.






I've noticed in the manual that it is possible to strip and maintain the
thermostat valve.
Seems straight forward enough, would it make any real difference?

Dave

On May 23, 11:43*am, "Dave" wrote:
if it were mine I'd have a look at the existing stat contacts first,
they may be wleded together. If so, part them and file the switch
surfaces smooth with a rat's tail file. Now, doing this will have
changed its setting a fair bit, so its important to watch closely
during first run and slowly turn the stat down until it switches off
once the primary circuit water gets hot.

I've noticed in the manual that it is possible to strip and maintain the
thermostat valve.
Seems straight forward enough, would it make any real difference?

Dave

The valve has nothing to do with it, the problem is the thermostat.
I'm assuming it is an electrical stat & valve, not something over
50yrs old. If my assumption is incorrect, all bets are off.


NT

I think the prize should go to NT ...... spot-on.
I stripped the thermostat, cleaned the contacts and re-assembled it.
The phial was cleaned with wirewool, smeared with heat tranfer silicon and
placed back in the phial pocket.
The boiler now fires up at different temperature settings as it should.
I'm hoping that as I'm now able to control the temperature of both HW and CH
it should also quiten the pump down a bit too (me thinking that the water in
the pump was cavitating due the water being too hot !).
Time will tell.
Many thanks again to all those who helped on this thread.
Dave

On Wed, 23 May 2012 10:23:46 +0100 (BST), "Dave Liquorice"
wrote:

On Tue, 22 May 2012 14:46:48 +0100, Dave wrote:

I've been looking for another stat for the boiler but as the boiler is
around 40+ years old, parts are quite thin on the ground.

So it's done it's moneys worth. Time to start looking for a
replacement I suspect that the efficiency of 40+ year old boiler
won't be very good. You could make considerable savings in gas
used... Take the opportunity to improve the control system as well
for additional savings.

Although I'd imagine that the payback time would be greater than the
life of the new boiler. Therefore I don't think it's worth replacing
just for financial reasons.

Probably not G rated so the boiler scrapage scheme might not help but
a few minutes on the SEDBUK site might be worth while, though
something that old might not be listed...

OTOH an older boiler is much simpler and I doubt many modern boilers
would last 40 years.
--
(\__/) M.
(='.'=) If a man stands in a forest and no woman is around
(")_(") is he still wrong?

On May 24, 10:31*am, Mark
wrote:
On Wed, 23 May 2012 10:23:46 +0100 (BST), "Dave Liquorice"

wrote:
On Tue, 22 May 2012 14:46:48 +0100, Dave wrote:

I've been looking for another stat for the boiler but as the boiler is
around 40+ years old, parts are quite thin on the ground.

So it's done it's moneys worth. Time to start looking for a
replacement I suspect that the efficiency of 40+ year old boiler
won't be very good. You could make considerable savings in gas
used... Take the opportunity to improve the control system as well
for additional savings.

Although I'd imagine that the payback time would be greater than the
life of the new boiler. *Therefore I don't think it's worth replacing
just for financial reasons.

Probably not G rated so the boiler scrapage scheme might not help but
a few minutes on the SEDBUK site might be worth while, though
something that old might not be listed...

OTOH an older boiler is much simpler and I doubt many modern boilers
would last 40 years.

+1 on both points.


NT