My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

It's due for a service, so hopefully the engineer will be able to
work out what's wrong when he comes, but I was hoping I might get an
idea of what to expect from the knowledgeable folks in this group.
All my attempts at Googling for info on the problem have only turned
up other kinds of problems, not mine.

By "quite often", I mean that it typically happens once or twice in
the time between the boiler starting up and shutting off. They are
usually isolated occurrences, but occasionally I've heard it happen
two or three times in a row with a few seconds in between.

The flue fan stays running, and I think the pilot light is staying
lit, as I don't hear the igniter spark, although I could be wrong if
the spark happens at the same time as the valve turning off (the
sound would be masked by the solenoid click). I tried watching the
pilot light through the inspection window for several minutes until
the boiler shut off, but as luck would have it the problem didn't
occur while I was watching.

The boiler is a Potterton of some sort, rebadged by British Gas as
a "Celsia F1", and is 15 years old. It had the main PCB replaced
about three years ago, but other than that has not had any faults.

Thanks in advance for any insights.

--
Geoff Clare

In article , Geoff Clare
writes
My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

It's due for a service, so hopefully the engineer will be able to
work out what's wrong when he comes, but I was hoping I might get an
idea of what to expect from the knowledgeable folks in this group.
All my attempts at Googling for info on the problem have only turned
up other kinds of problems, not mine.

By "quite often", I mean that it typically happens once or twice in
the time between the boiler starting up and shutting off. They are
usually isolated occurrences, but occasionally I've heard it happen
two or three times in a row with a few seconds in between.

The flue fan stays running, and I think the pilot light is staying
lit, as I don't hear the igniter spark, although I could be wrong if
the spark happens at the same time as the valve turning off (the
sound would be masked by the solenoid click). I tried watching the
pilot light through the inspection window for several minutes until
the boiler shut off, but as luck would have it the problem didn't
occur while I was watching.

The boiler is a Potterton of some sort, rebadged by British Gas as
a "Celsia F1", and is 15 years old. It had the main PCB replaced
about three years ago, but other than that has not had any faults.


That is not a boiler I am familiar with.

Are you sure it is turning off as it could just be modulating down.

Some older boilers can modulate their output but only step between high
and low rather that the continuously variable modulation of modern
boilers. The noise you are hearing may just be the modulation solenoid
switching between high and low which would be normal if it had been
running for some time. Even switching the burner off completely may just
be the boiler thermostat reaching temperature and shutting down the
flame.
--
fred
it's a ba-na-na . . . .

Geoff Clare wrote:
My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

Friend had a pretty ancient boiler (fixed pilot light job) that did the
same sort of thing. Turned out to be a dodgy connection to the gas valve
(either the external wire or the internal one to the actuator coil, I
forget now.) Quick fix and didn't do it again.

--
Scott

fred wrote:

In article , Geoff Clare
writes
My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

It's due for a service, so hopefully the engineer will be able to
work out what's wrong when he comes, but I was hoping I might get an
idea of what to expect from the knowledgeable folks in this group.
All my attempts at Googling for info on the problem have only turned
up other kinds of problems, not mine.

By "quite often", I mean that it typically happens once or twice in
the time between the boiler starting up and shutting off. They are
usually isolated occurrences, but occasionally I've heard it happen
two or three times in a row with a few seconds in between.

The flue fan stays running, and I think the pilot light is staying
lit, as I don't hear the igniter spark, although I could be wrong if
the spark happens at the same time as the valve turning off (the
sound would be masked by the solenoid click). I tried watching the
pilot light through the inspection window for several minutes until
the boiler shut off, but as luck would have it the problem didn't
occur while I was watching.

The boiler is a Potterton of some sort, rebadged by British Gas as
a "Celsia F1", and is 15 years old. It had the main PCB replaced
about three years ago, but other than that has not had any faults.


That is not a boiler I am familiar with.

It looks very similar to these:

http://www.partsarena.co.uk/baxi/Sys...999/page23.gif

http://www.rwl-supplies.co.uk/img/boiler1.jpg

if that's any help.

Are you sure it is turning off as it could just be modulating down.

I can hear the characteristic soft "whump" of the gas igniting after
the valve opens again.

Some older boilers can modulate their output but only step between high
and low rather that the continuously variable modulation of modern
boilers. The noise you are hearing may just be the modulation solenoid
switching between high and low which would be normal if it had been
running for some time.

That sounds like normal operation for such boilers - which means
it would have been doing that all along, but it has only started
doing it in the last few months.

Even switching the burner off completely may just
be the boiler thermostat reaching temperature and shutting down the
flame.

Okay, but then it would be odd for it only to be off for half a
second.

What normally seems to happen when the thermostat reaches temperature
is both valves (main burner and pilot light) close and the fan stops,
so just the pump (which is located elsewhere) is left running. Then
when the circulating water has cooled enough, the boiler starts up
again (fan first, then pilot light, then main burner).

--
Geoff Clare

I wrote:

My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

It's due for a service, so hopefully the engineer will be able to
work out what's wrong when he comes, but I was hoping I might get an
idea of what to expect from the knowledgeable folks in this group.
All my attempts at Googling for info on the problem have only turned
up other kinds of problems, not mine.

By "quite often", I mean that it typically happens once or twice in
the time between the boiler starting up and shutting off. They are
usually isolated occurrences, but occasionally I've heard it happen
two or three times in a row with a few seconds in between.

The flue fan stays running, and I think the pilot light is staying
lit, as I don't hear the igniter spark, although I could be wrong if
the spark happens at the same time as the valve turning off (the
sound would be masked by the solenoid click). I tried watching the
pilot light through the inspection window for several minutes until
the boiler shut off, but as luck would have it the problem didn't
occur while I was watching.

The boiler is a Potterton of some sort, rebadged by British Gas as
a "Celsia F1", and is 15 years old. It had the main PCB replaced
about three years ago, but other than that has not had any faults.

Thanks in advance for any insights.

I'm starting to think that maybe I'm wrong about the pilot light
staying lit. If the pilot light went out, it seems plausible that
the control box would turn off the main gas valve and immediately
re-light the pilot light. The short time delay between the valve
starting to close and the click when it closes could mean that the
click masks the sound of the spark that lights the pilot light.

Does that make sense?

--
Geoff Clare

Geoff Clare wrote:

I'm starting to think that maybe I'm wrong about the pilot light
staying lit. If the pilot light went out, it seems plausible that
the control box would turn off the main gas valve and immediately
re-light the pilot light. The short time delay between the valve
starting to close and the click when it closes could mean that the
click masks the sound of the spark that lights the pilot light.

You might want to start a new thread - I only looked in as I was looking
for an old post somewhere.

I don't think a pilot lights would relight anywhere near that quickly
after they've been running, too much polluted air round them.

Assuming you've checked the gas valve connections, next stop is the
thermocouple. It could be signs of one that's getting a bit marginal.

--
Scott

On Sunday, 15 September 2013 10:17:24 UTC+1, Geoff Clare wrote:
My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

It's due for a service, so hopefully the engineer will be able to
work out what's wrong when he comes, but I was hoping I might get an
idea of what to expect from the knowledgeable folks in this group.
All my attempts at Googling for info on the problem have only turned
up other kinds of problems, not mine.

By "quite often", I mean that it typically happens once or twice in
the time between the boiler starting up and shutting off. They are
usually isolated occurrences, but occasionally I've heard it happen
two or three times in a row with a few seconds in between.

The flue fan stays running, and I think the pilot light is staying
lit, as I don't hear the igniter spark, although I could be wrong if
the spark happens at the same time as the valve turning off (the
sound would be masked by the solenoid click). I tried watching the
pilot light through the inspection window for several minutes until
the boiler shut off, but as luck would have it the problem didn't
occur while I was watching.

The boiler is a Potterton of some sort, rebadged by British Gas as
a "Celsia F1", and is 15 years old. It had the main PCB replaced
about three years ago, but other than that has not had any faults.

Thanks in advance for any insights.

--
Geoff Clare

Hi Goeoff, I am having a similar problem with my Potterton boiler, it was intermittant like yours, but now its happening all the time. Did you find out what was causing it? Any help would be much appreciated. Kind regards. Paul

On Monday, 19 March 2018 07:00:38 UTC, wrote:
On Sunday, 15 September 2013 10:17:24 UTC+1, Geoff Clare wrote:
My boiler is working (it's heating the water that goes through it),
but something isn't right with it because quite often I can hear
the main gas valve turn off, and then on again about half a second
later, while the boiler is running.

It's due for a service, so hopefully the engineer will be able to
work out what's wrong when he comes, but I was hoping I might get an
idea of what to expect from the knowledgeable folks in this group.
All my attempts at Googling for info on the problem have only turned
up other kinds of problems, not mine.

By "quite often", I mean that it typically happens once or twice in
the time between the boiler starting up and shutting off. They are
usually isolated occurrences, but occasionally I've heard it happen
two or three times in a row with a few seconds in between.

The flue fan stays running, and I think the pilot light is staying
lit, as I don't hear the igniter spark, although I could be wrong if
the spark happens at the same time as the valve turning off (the
sound would be masked by the solenoid click). I tried watching the
pilot light through the inspection window for several minutes until
the boiler shut off, but as luck would have it the problem didn't
occur while I was watching.

The boiler is a Potterton of some sort, rebadged by British Gas as
a "Celsia F1", and is 15 years old. It had the main PCB replaced
about three years ago, but other than that has not had any faults.

Thanks in advance for any insights.

--
Geoff Clare

Hi Goeoff, I am having a similar problem with my Potterton boiler, it was intermittant like yours, but now its happening all the time. Did you find out what was causing it? Any help would be much appreciated. Kind regards. Paul

we last saw him here about 5 years ago. Feel free to give us more details of your problem.


NT