Valliant Turbo Max Plus boiler randomly coming on

BobRachet

ThisIsWeird said:

BobRachet said:

ThisIsWeird said:

Bob, is it a 'combi' boiler? Ie, you do NOT have a hot water tank?

When it comes on, does it actually heat up your radiators?

Yeah it's a combi and the heating goes on all the way on, heating the entire system. I've turned my radiators off because of this but now it's winter that is a pain to keep altering.

Thanks. And what type of boiler controls do you have - is the room stat wireless, for example? A Programmable type?

Make and model, please?

Timeswitch 120, a digital panel. I think everything is on the boiler, then it's temp regulators on the radiators.

Ayr_Rage

Closing off all the TRVs on the radiators is not a good idea if the heating circuit is activating randomly, the heat needs to go somewhere.

The diverter valve idea is a red herring, it does not make the boiler fire up, just determines where the water goes, either hot water of heating.

Is there a room thermostat on the wall anywhere?

You need to find what part of the system is calling for heat.

FreeBear

BobRachet said:

FreeBear said:

BobRachet said:

ThisIsWeird said:

Bob, is it a 'combi' boiler? Ie, you do NOT have a hot water tank?

When it comes on, does it actually heat up your radiators?

Yeah it's a combi and the heating goes on all the way on, heating the entire system. I've turned my radiators off because of this but now it's winter that is a pain to keep altering.

Could be a faulty diverter valve inside the boiler - This would need a Gas Safe engineer to swap it out. But... I would have expected an error code to appear on the front panel.

When was the boiler last serviced ?

It looks like 2020 when it was last serviced.

The Turbomax range were (as best I can tell) are all non-condensing boilers as are the ThermoCompact range. From 2005, it became mandatory to fit condensing boilers, so yours is at least 20 years old. If it was last serviced in 2020, it is well overdue for another one.

Ayr_Rage said: The diverter valve idea is a red herring, it does not make the boiler fire up, just determines where the water goes, either hot water of heating.

If the comfort mode is enabled, and the diverter valve is stuck, that might go some way to explaining why the radiators are getting hot at seemingly random intervals. So not a red herring, just a possibility bearing in mind the age of the boiler and lack of regular servicing.

BobRachet

Ayr_Rage said:

Closing off all the TRVs on the radiators is not a good idea if the heating circuit is activating randomly, the heat needs to go somewhere.

The diverter valve idea is a red herring, it does not make the boiler fire up, just determines where the water goes, either hot water of heating.

Is there a room thermostat on the wall anywhere?

You need to find what part of the system is calling for heat.

I've looked all over and can't find one, I'm guessing it is just controlled by the timer and the heat dials on the radiators.

Ayr_Rage

FreeBear said:

BobRachet said:

FreeBear said:

BobRachet said:

ThisIsWeird said:

Bob, is it a 'combi' boiler? Ie, you do NOT have a hot water tank?

When it comes on, does it actually heat up your radiators?

Yeah it's a combi and the heating goes on all the way on, heating the entire system. I've turned my radiators off because of this but now it's winter that is a pain to keep altering.

Could be a faulty diverter valve inside the boiler - This would need a Gas Safe engineer to swap it out. But... I would have expected an error code to appear on the front panel.

When was the boiler last serviced ?

It looks like 2020 when it was last serviced.

The Turbomax range were (as best I can tell) are all non-condensing boilers as are the ThermoCompact range. From 2005, it became mandatory to fit condensing boilers, so yours is at least 20 years old. If it was last serviced in 2020, it is well overdue for another one.

Ayr_Rage said: The diverter valve idea is a red herring, it does not make the boiler fire up, just determines where the water goes, either hot water of heating.

If the comfort mode is enabled, and the diverter valve is stuck, that might go some way to explaining why the radiators are getting hot at seemingly random intervals. So not a red herring, just a possibility bearing in mind the age of the boiler and lack of regular servicing.

See the OPs post, it's been coming on and staying on for over an hour and can only be stopped with a reset.

BobRachet

Ayr_Rage said:

FreeBear said:

BobRachet said:

FreeBear said:

BobRachet said:

ThisIsWeird said:

Bob, is it a 'combi' boiler? Ie, you do NOT have a hot water tank?

When it comes on, does it actually heat up your radiators?

Yeah it's a combi and the heating goes on all the way on, heating the entire system. I've turned my radiators off because of this but now it's winter that is a pain to keep altering.

Could be a faulty diverter valve inside the boiler - This would need a Gas Safe engineer to swap it out. But... I would have expected an error code to appear on the front panel.

When was the boiler last serviced ?

It looks like 2020 when it was last serviced.

The Turbomax range were (as best I can tell) are all non-condensing boilers as are the ThermoCompact range. From 2005, it became mandatory to fit condensing boilers, so yours is at least 20 years old. If it was last serviced in 2020, it is well overdue for another one.

Ayr_Rage said: The diverter valve idea is a red herring, it does not make the boiler fire up, just determines where the water goes, either hot water of heating.

If the comfort mode is enabled, and the diverter valve is stuck, that might go some way to explaining why the radiators are getting hot at seemingly random intervals. So not a red herring, just a possibility bearing in mind the age of the boiler and lack of regular servicing.

See the OPs post, it's been coming on and staying on for over an hour and can only be stopped with a reset.

The fact the reset on the timer fixes it makes me wonder if it is the timer. I can see they are not that expensive so might order one.

ThisIsWeird

Picture of this timer, please? And a pic of your rad TRV.
There should be a separate room temp controller, unless, say, the TRVs are 'Smart'?

forgotmyname

We had a similar issue with the boiler randomly kicking in and even heating well above the set temperature, swapped out the
room thermostat with a simple Honeywell one and all cured.

Previously it would switch the boiler on and the radiators would get really hot and still getting hotter even though the house was
above the temperature set. After fitting the new thermostat the boiler fires up for much shorter periods and instead of having
boiling hot radiators they are just moderately warm which feels much nicer and the temperature is really stable no wild
fluctuations.