I have a boiler that is cutting out. I don't know the model number, but it
has a "ravenheat" logo on it.

It is a gas boiler, I have the system pressurised to 1 bar, and it does
instant hot water. All the radiators have TRVs on them (yes, all), and
there is no room stat. (Ex council house, cheap council installation)

I have tried putting one radiator valve on full to see if it is overheating
and tripping out, but it still does. I have also tried altering the water
temperature (both tap and rads), with no effect.

After the CH has been on for a while, I notice the rads are cold, and the
boiler fan is going, but the flame is not burning. Lowering the rad
thermostat on the boiler until it clicks, then putting it back resets it,
and it fires up fine. Also, clicking the time clock off and on does the
trick.

Any ideas?

Thanks

Bob

In an earlier contribution to this discussion,
Bob Smith <(E-Mail Removed)> wrote:

> I have a boiler that is cutting out. I don't know the model number,
> but it has a "ravenheat" logo on it.
>
> It is a gas boiler, I have the system pressurised to 1 bar, and it
> does instant hot water. All the radiators have TRVs on them (yes,
> all), and there is no room stat. (Ex council house, cheap council
> installation)
>
> I have tried putting one radiator valve on full to see if it is
> overheating and tripping out, but it still does. I have also tried
> altering the water temperature (both tap and rads), with no effect.
>
> After the CH has been on for a while, I notice the rads are cold, and
> the boiler fan is going, but the flame is not burning. Lowering the
> rad thermostat on the boiler until it clicks, then putting it back
> resets it, and it fires up fine. Also, clicking the time clock off
> and on does the trick.
>
> Any ideas?
>
> Thanks
>
> Bob


Well one thing's clear - the boiler's overheat stat is tripping - and has to
be manually reset before the boiler will fire again.

What isn't so clear is *why*. This could be due to any of several causes,
which need investigating, including:
* faulty overheat stat (possibly the prime suspect)
* insufficient circulation to carry the residual heat away after the main
stat turns the flame off (This could certainly be the case if *all* the TRVs
are closed and *may* be the case if only one TRV is open. There could also
be an intermittent pump problem - but that doesn't sound too likely.) [If
circulation *is* the problem, I would expect turning down the boiler stat to
improve matters - since there's more leaway for the temperature to rise
before tripping the overheat stat].
* incorrectly wired pump (This is probably the least likely, and would only
really apply if the whole lot were turned on and off with a room stat - in
which case it must be wired to keep the pump running for a while after
turning the boiler off)

Do you have a means of measuring flow temperature. [If not, it may be a good
time to invest in an instant reading non-contact IR device from CPC for
£30 - I don't know how I ever managed without mine!] If you can check the
boiler outlet pipe temperature immediately after it trips, you can see
whether the temperature *is* excessive. If it's not, it points to the
overheat stat. If you suspect the overheat stat, try bridging it - but keep
a very close eye on the system while running bridged! If this cures it
without any side effects, fit a new overheat stat. If you get lots of
gurgling and banging, , turn it off a bit smartish! In this case, it really
*is* overheating and you need to look at some of the other possibilities.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!

"Set Square" <(E-Mail Removed)> wrote in message
news:btps8j$a86q4$(E-Mail Removed)...
> In an earlier contribution to this discussion,
> Bob Smith <(E-Mail Removed)> wrote:
>
> > I have a boiler that is cutting out. I don't know the model number,
> > but it has a "ravenheat" logo on it.
> >
> > It is a gas boiler, I have the system pressurised to 1 bar, and it
> > does instant hot water. All the radiators have TRVs on them (yes,
> > all), and there is no room stat. (Ex council house, cheap council
> > installation)
> >
> > I have tried putting one radiator valve on full to see if it is
> > overheating and tripping out, but it still does. I have also tried
> > altering the water temperature (both tap and rads), with no effect.
> >
> > After the CH has been on for a while, I notice the rads are cold, and
> > the boiler fan is going, but the flame is not burning. Lowering the
> > rad thermostat on the boiler until it clicks, then putting it back
> > resets it, and it fires up fine. Also, clicking the time clock off
> > and on does the trick.
> >
> > Any ideas?
> >
> > Thanks
> >
> > Bob
>
>
> Well one thing's clear - the boiler's overheat stat is tripping - and has
to
> be manually reset before the boiler will fire again.
>
> What isn't so clear is *why*. This could be due to any of several causes,
> which need investigating, including:
> * faulty overheat stat (possibly the prime suspect)
> * insufficient circulation to carry the residual heat away after the main
> stat turns the flame off (This could certainly be the case if *all* the
TRVs
> are closed and *may* be the case if only one TRV is open. There could also
> be an intermittent pump problem - but that doesn't sound too likely.) [If
> circulation *is* the problem, I would expect turning down the boiler stat
to
> improve matters - since there's more leaway for the temperature to rise
> before tripping the overheat stat].
> * incorrectly wired pump (This is probably the least likely, and would onl
y
> really apply if the whole lot were turned on and off with a room stat - in
> which case it must be wired to keep the pump running for a while after
> turning the boiler off)
>
> Do you have a means of measuring flow temperature. [If not, it may be a
good
> time to invest in an instant reading non-contact IR device from CPC for
> £30 - I don't know how I ever managed without mine!] If you can check the
> boiler outlet pipe temperature immediately after it trips, you can see
> whether the temperature *is* excessive. If it's not, it points to the
> overheat stat. If you suspect the overheat stat, try bridging it - but
keep
> a very close eye on the system while running bridged! If this cures it
> without any side effects, fit a new overheat stat. If you get lots of
> gurgling and banging, , turn it off a bit smartish! In this case, it
really
> *is* overheating and you need to look at some of the other possibilities.
> --
> Cheers,
> Set Square
> ______
> Please reply to newsgroup. Reply address is Black Hole!
>
>

Some useful ideas, thanks - I never get to it just after it has tripped to
take a temperature though.

The pump has a 3 minute overrun. If there *is* a (can't remember the name -
thingy in case all rads are off) would the boiler stop heating in time for
the small amount of water to not overheat?

If it has tripped out because of too much heat, would the act of turning
down the radiator temp knob until it clicks, then putting it back be enough
to reset it? (the boiler in my last house, you had to take the case off and
open a metal enclosure to get to the thermal cutout reset).

I will turn the temp down, and leave 2 rads on full to see if it cuts down
the frequency of tripouts.

Bob

In an earlier contribution to this discussion,
Bob Smith <(E-Mail Removed)> wrote:

> "Set Square" <(E-Mail Removed)> wrote in message
> news:btps8j$a86q4$(E-Mail Removed)...
>> In an earlier contribution to this discussion,
>> Bob Smith <(E-Mail Removed)> wrote:
>>
>>> I have a boiler that is cutting out. I don't know the model
>>> number, but it has a "ravenheat" logo on it.
>>>
>>> It is a gas boiler, I have the system pressurised to 1 bar, and it
>>> does instant hot water. All the radiators have TRVs on them (yes,
>>> all), and there is no room stat. (Ex council house, cheap council
>>> installation)
>>>
>>> I have tried putting one radiator valve on full to see if it is
>>> overheating and tripping out, but it still does. I have also tried
>>> altering the water temperature (both tap and rads), with no effect.
>>>
>>> After the CH has been on for a while, I notice the rads are cold,
>>> and the boiler fan is going, but the flame is not burning.
>>> Lowering the rad thermostat on the boiler until it clicks, then
>>> putting it back resets it, and it fires up fine. Also, clicking
>>> the time clock off and on does the trick.
>>>
>>> Any ideas?
>>>
>>> Thanks
>>>
>>> Bob
>>
>>
>> Well one thing's clear - the boiler's overheat stat is tripping -
>> and has to be manually reset before the boiler will fire again.
>>
>> What isn't so clear is *why*. This could be due to any of several
>> causes, which need investigating, including:
>> * faulty overheat stat (possibly the prime suspect)
>> * insufficient circulation to carry the residual heat away after the
>> main stat turns the flame off (This could certainly be the case if
>> *all* the TRVs are closed and *may* be the case if only one TRV is
>> open. There could also be an intermittent pump problem - but that
>> doesn't sound too likely.) [If circulation *is* the problem, I would
>> expect turning down the boiler stat to improve matters - since
>> there's more leaway for the temperature to rise before tripping the
>> overheat stat]. * incorrectly wired pump (This is probably the least
>> likely, and would onl y really apply if the whole lot were turned on
>> and off with a room stat - in which case it must be wired to keep
>> the pump running for a while after turning the boiler off)
>>
>> Do you have a means of measuring flow temperature. [If not, it may
>> be a good time to invest in an instant reading non-contact IR device
>> from CPC for £30 - I don't know how I ever managed without mine!] If
>> you can check the boiler outlet pipe temperature immediately after
>> it trips, you can see whether the temperature *is* excessive. If
>> it's not, it points to the overheat stat. If you suspect the
>> overheat stat, try bridging it - but keep a very close eye on the
>> system while running bridged! If this cures it without any side
>> effects, fit a new overheat stat. If you get lots of gurgling and
>> banging, , turn it off a bit smartish! In this case, it really *is*
>> overheating and you need to look at some of the other possibilities.
>> --
>> Cheers,
>> Set Square
>> ______
>> Please reply to newsgroup. Reply address is Black Hole!
>>
>>
>
> Some useful ideas, thanks - I never get to it just after it has
> tripped to take a temperature though.

You could try to induce it to misbehave though, by turning off the CH at the
programmer when the boiler is running at full chat. Verify that the pump
continues to run, and monitor the outlet temperature for a couple of
minutes.
>
> The pump has a 3 minute overrun. If there *is* a (can't remember the
> name - thingy in case all rads are off) would the boiler stop heating
> in time for the small amount of water to not overheat?

You're probably referring to an automatic by-pass valve. If you had one -
which you probably don't - it would open if the pump were running but the
water had nowhere else to go because all the TRVs were closed. As long as
the pump kept going for a little while after the boiler stopped firing, this
should be sufficient to carry the heat away without the trip operating.
>
> If it has tripped out because of too much heat, would the act of
> turning down the radiator temp knob until it clicks, then putting it
> back be enough to reset it? (the boiler in my last house, you had to
> take the case off and open a metal enclosure to get to the thermal
> cutout reset).

Probably. There are various designs of over-heat stat. On my MkI Baxi Solo
boiler, a little button pops out which has to be pushed in to reset it. On
more recent versions of the same boiler, the reset procedure is to turn the
thermostat knob right down and then back up again. Yours is probably like
that.
>
> I will turn the temp down, and leave 2 rads on full to see if it cuts
> down the frequency of tripouts.
>
> Bob


Let us know how you get on!
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!

>>
>> I will turn the temp down, and leave 2 rads on full to see if it cuts
>> down the frequency of tripouts.
>
>
> Let us know how you get on!

Well, I turned the heat down, and put 2 rads on full, and it still cuts out.
I think it is even more than before, but it is a seemingly random thing
anyway.

I think the thermal cutout thing is working, because it can go for a couple
of hours, and the rads do feel hot, so i don't think it is cutting out
early.

I fiddled with the pump. It has 3 speed settings, and all three sound
different, although it may not be fully functional. When the switch is
between settings, the pump stops (break before make switch), and the water
sounds like it is boiling, although it did not cut out (I didn't hold it
there long).

I don't have a thermometer to check the water temperature.

The firing up sequence sounds like:

Demand for heat
flame light comes on dull
small click: fan starts
pause
flame light goes bright
large click (gas valve)
whoomph (gas lights)
flame light goes off (as though it is a "request to light" indicator)

When I find it has cut out, the fan is going, and the light is on bright,
and no gas is being used up.

Bob

In an earlier contribution to this discussion,
Bob Smith <(E-Mail Removed)> wrote:

>>> I will turn the temp down, and leave 2 rads on full to see if it
>>> cuts down the frequency of tripouts.
>>
>>
>> Let us know how you get on!
>
> Well, I turned the heat down, and put 2 rads on full, and it still
> cuts out. I think it is even more than before, but it is a seemingly
> random thing anyway.
>
> I think the thermal cutout thing is working, because it can go for a
> couple of hours, and the rads do feel hot, so i don't think it is
> cutting out early.
>
> I fiddled with the pump. It has 3 speed settings, and all three sound
> different, although it may not be fully functional. When the switch
> is between settings, the pump stops (break before make switch), and
> the water sounds like it is boiling, although it did not cut out (I
> didn't hold it there long).
>
> I don't have a thermometer to check the water temperature.
>
> The firing up sequence sounds like:
>
> Demand for heat
> flame light comes on dull
> small click: fan starts
> pause
> flame light goes bright
> large click (gas valve)
> whoomph (gas lights)
> flame light goes off (as though it is a "request to light" indicator)
>
> When I find it has cut out, the fan is going, and the light is on
> bright, and no gas is being used up.
>
> Bob


This is all very interesting! I'm no longer convinced that it *is* the
overheat stat operating.

When my boiler cuts out on its overheat stat, it cuts power to everything -
so no fan, no LEDs, no ignition.

Unless the internal wiring of your boiler is different from mine (and it may
well be!) the fact that the fan is still running suggests to me that the
prpblem is downstream of the fan - like the pressure switch or ignition
system - or even the main PCB. Whatever it is, it seems that turning it off
and on resets something and gets it going again.

Can you remind me of the make and model of your boiler. Do you have an
installation manual with internal wiring diagrams? Does it have a
fault-finding chart?
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!

Set Square wrote:
> In an earlier contribution to this discussion,
> Bob Smith <(E-Mail Removed)> wrote:
>
>>>> I will turn the temp down, and leave 2 rads on full to see if it
>>>> cuts down the frequency of tripouts.
>>>
>>>
>>> Let us know how you get on!
>>
>> Well, I turned the heat down, and put 2 rads on full, and it still
>> cuts out. I think it is even more than before, but it is a seemingly
>> random thing anyway.
>>
>> I think the thermal cutout thing is working, because it can go for a
>> couple of hours, and the rads do feel hot, so i don't think it is
>> cutting out early.
>>
>> I fiddled with the pump. It has 3 speed settings, and all three
>> sound different, although it may not be fully functional. When the
>> switch
>> is between settings, the pump stops (break before make switch), and
>> the water sounds like it is boiling, although it did not cut out (I
>> didn't hold it there long).
>>
>> I don't have a thermometer to check the water temperature.
>>
>> The firing up sequence sounds like:
>>
>> Demand for heat
>> flame light comes on dull
>> small click: fan starts
>> pause
>> flame light goes bright
>> large click (gas valve)
>> whoomph (gas lights)
>> flame light goes off (as though it is a "request to light" indicator)
>>
>> When I find it has cut out, the fan is going, and the light is on
>> bright, and no gas is being used up.
>>
>> Bob
>
>
> This is all very interesting! I'm no longer convinced that it *is* the
> overheat stat operating.
>
> When my boiler cuts out on its overheat stat, it cuts power to
> everything - so no fan, no LEDs, no ignition.
>
> Unless the internal wiring of your boiler is different from mine (and
> it may well be!) the fact that the fan is still running suggests to
> me that the prpblem is downstream of the fan - like the pressure
> switch or ignition system - or even the main PCB. Whatever it is, it
> seems that turning it off and on resets something and gets it going
> again.
>
> Can you remind me of the make and model of your boiler. Do you have an
> installation manual with internal wiring diagrams? Does it have a
> fault-finding chart?

It is a Ravenheat, with no model number or identification (unless it is
under the plumbers "call me" sticker). There was no manual when we moved
into the house. I could take a picture with and without it's front cover on
(ooer missis!) if that would help.

Bob

In an earlier contribution to this discussion,
Bob Smith <(E-Mail Removed)> wrote:

>
> It is a Ravenheat, with no model number or identification (unless it
> is under the plumbers "call me" sticker). There was no manual when
> we moved into the house. I could take a picture with and without
> it's front cover on (ooer missis!) if that would help.
>
> Bob


It might help someone identify it - not me, I'm afraid - I only know about
the boilers I have owned.

Since you don't have an installation manual, my thoughts were that we may be
able to download one from the maker's website. But we *do* need to know the
model. There may be a plate inside the casing, if it doesn't say on the
outside.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!

>
>>
>> It is a Ravenheat, with no model number or identification (unless it
>> is under the plumbers "call me" sticker). There was no manual when
>> we moved into the house. I could take a picture with and without
>> it's front cover on (ooer missis!) if that would help.
>>
>> Bob
>
>
> It might help someone identify it - not me, I'm afraid - I only know
> about the boilers I have owned.
>
> Since you don't have an installation manual, my thoughts were that we
> may be able to download one from the maker's website. But we *do*
> need to know the model. There may be a plate inside the casing, if
> it doesn't say on the outside.
> --

OK, will look for a plate, and peel the plumber's sticker off. Failing
that, I will take some piccies. Then I could find a PDF or something with
te wiring diagram in.

Bob

In an earlier contribution to this discussion,
Set Square <(E-Mail Removed)> wrote:

> In an earlier contribution to this discussion,
> Bob Smith <(E-Mail Removed)> wrote:
>
>>
>> It is a Ravenheat, with no model number or identification (unless it
>> is under the plumbers "call me" sticker). There was no manual when
>> we moved into the house. I could take a picture with and without
>> it's front cover on (ooer missis!) if that would help.
>>
>> Bob
>
>
> It might help someone identify it - not me, I'm afraid - I only know
> about the boilers I have owned.
>
> Since you don't have an installation manual, my thoughts were that we
> may be able to download one from the maker's website. But we *do*
> need to know the model. There may be a plate inside the casing, if
> it doesn't say on the outside.
> --
> Cheers,
> Set Square
> ______
> Please reply to newsgroup. Reply address is Black Hole!


Just had a look at the Ravenheat site. They do have downloadable manuals -
at least for their current boilers. Have a look at
http://www.ravenheat.co.uk/manuals.htm
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is Black Hole!