Hi

I have a Baxi Bermuda boiler and, after it has been on for about an
hour, the bathroom radiator has been getting very hot. It is the only
radiator without a thermostat.
I turn the thermostat, mounted on the boiler, down to LOW but still
the radiators are too hot.
There are no other problems with the system and the temporary solution
is just to switch the heating off for a while till things cool down.
There is no knocking sound to indicate a faulty pump etc.

I'm guessing that the boiler thermostat is faulty. Is there any way
that I can test it? Is it easy to replace?

thanks for your help
Nigel

BluesCon wrote:

I have a Baxi Bermuda boiler and, after it has been on for about an
hour, the bathroom radiator has been getting very hot. It is the only
radiator without a thermostat.
I turn the thermostat, mounted on the boiler, down to LOW but still
the radiators are too hot.
There are no other problems with the system and the temporary solution
is just to switch the heating off for a while till things cool down.
There is no knocking sound to indicate a faulty pump etc.

I'm guessing that the boiler thermostat is faulty. Is there any way
that I can test it? Is it easy to replace?

I'm not familiar with your boiler, so won't comment on it (I'm sure
someone who is will be along shortly). But as for the radiator, how
about turning down the lockshield valve?

--
Grunff

"BluesCon" wrote in message
om...
Hi

I have a Baxi Bermuda boiler and, after it has been on for about an
hour, the bathroom radiator has been getting very hot. It is the only
radiator without a thermostat.
I turn the thermostat, mounted on the boiler, down to LOW but still
the radiators are too hot.
There are no other problems with the system and the temporary solution
is just to switch the heating off for a while till things cool down.
There is no knocking sound to indicate a faulty pump etc.

I'm guessing that the boiler thermostat is faulty. Is there any way
that I can test it? Is it easy to replace?

It might not be the boiler stat. How hot is too hot by the way? If you turn
your boiler stat way down it's still going to be kicking out water at 60 C
or more (I've never actually measured it so I don't know) which can feel
very hot to the hand. As Grunff suggested turning the valve down might be a
better solution. If your boiler stat was faulty and overheating you'd
probably get kettleing, which you'd hear.

--
Malc

In an earlier contribution to this discussion,
BluesCon wrote:

Hi

I have a Baxi Bermuda boiler and, after it has been on for about an
hour, the bathroom radiator has been getting very hot. It is the only
radiator without a thermostat.
I turn the thermostat, mounted on the boiler, down to LOW but still
the radiators are too hot.
There are no other problems with the system and the temporary solution
is just to switch the heating off for a while till things cool down.
There is no knocking sound to indicate a faulty pump etc.

I'm guessing that the boiler thermostat is faulty. Is there any way
that I can test it? Is it easy to replace?

thanks for your help
Nigel

Is there a room thermostat, mounted on a wall, somewhere? If not, there
should be - to turn the whole lot off when all rooms are up to temperature.

If the boiler stat is working, it should cycle the burner on and off every
few minutes - unless the weather's so cold that the boiler needs to run flat
out to keep up. The best way to check it is to measure the temperature of
the water flowing out of the boiler. This is best done using a non-contact
IR thermometer, pointed at the outlet pipe. This should be somewhere between
70 and 80 degC depending on the thermostat setting.

If the boiler stat *is* faulty, it's not *too* difficult to replace. You
need first to remove the gas fire, in order to get at the boiler controls.
You can *probably* replace the stat without disconnecting the boiler
controls and sliding them out from under the heat exchanger - I can't
remember exactly since it's a long time since I owned one. The thermostat
assembly is a little box with a knob and a couple of electrical
connections - and a capillary tube with a bulb on the end, which has to be
inserted into a pocket at the top of the heat exchanger.
--
Cheers,
Set Square
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"Set Square" wrote in message ...
Is there a room thermostat, mounted on a wall, somewhere? If not, there
should be - to turn the whole lot off when all rooms are up to temperature.

If the boiler stat is working, it should cycle the burner on and off every
few minutes - unless the weather's so cold that the boiler needs to run flat
out to keep up.

Thanks for the responses.
We have had this system for 14 years and this problem only started
around 6 months ago. The lockshield valve's have not been adjusted in
this time so I dont feel that this is the root of the prob. I will
keep it in mind, thanks.

There is no room thermostat, never has been. I just use the boiler
stat to adjust the overall tempoerature.

The burner appears to be staying on all the time and not cycling on
and off. It will go off when I turn the boiler stat down to LOW but
otherwise appears to stay ON. I will check this again before posting
back. I'm away for a few days so may not post back on this till the
weekend.

In an earlier contribution to this discussion,
BluesCon wrote:


The burner appears to be staying on all the time and not cycling on
and off. It will go off when I turn the boiler stat down to LOW but
otherwise appears to stay ON. I will check this again before posting
back. I'm away for a few days so may not post back on this till the
weekend.

It's important to check the flow temperature then. You just *could* be using
the entire boiler output without the water temperature ever getting hot
enough to turn the stat off.

One other thing to check that is that the bulb of the thermostat is making
good contact with the heat exchanger. I seem to remember that there's
supposed to be some sort of paste in the pocket to ensure good heat
transfer.
--
Cheers,
Set Square
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Problem fixed, thanks for all your help. It turned out to be the
thermostat after all. I tried reseating the thermostat bulb initialy
but to no avail. A new thermostat has seloved the issue. Although I
had reconned on this being faulty from the beginning your help and
advice helped confirm my suspisions. Cheers