Valliant Turbo Max Plus boiler randomly coming on

BobRachet

I have moved to a new place that has a Valliant Turbo Max Plus boiler, at least I think it is, there is no model name written anywhere on it but I have found an online manual that matches, it could also be a ThermoCompact.

Occasionally the heating comes on a totally random time, this happened in summer a few times so I don't think it would  be the froststat. When the heating comes on like this I have checked the control panel and the heating is showing as been off as it should be. I have the physical heating dial switched to the off position, so it shouldn't be coming on at all. I only seem to be able to stop the heating being on by pressing the reset button on the timer unit.

It seems to happen not that often, maybe once every few weeks.

As I am sometimes away for weeks at a time I really don't want this happening for that length of time, especially in summer. Is this a common problem and easily repaired?

Ayr_Rage

How long does it run for when it "randomly comes on"?

Along with frost protection I believe some boilers have a feature to run the pump to prevent it seizing when not in use for some time.

FreeBear

Ayr_Rage said: Along with frost protection I believe some boilers have a feature to run the pump to prevent it seizing when not in use for some time.

I was under the impression that pump cycling didn't involve the boiler firing up.

If this Vaillant is a combi boiler, it is likely that it has been set to run in "comfort" mode - This means the boiler will fire up at regular intervals to keep the internals hot so you don't have to wait too long for hot water. Turn this "feature" off, and you save gas as well as reduced wear & tear. But it does mean you have to wait a little longer for hot water.

BobRachet

Ayr_Rage said:

How long does it run for when it "randomly comes on"?

Along with frost protection I believe some boilers have a feature to run the pump to prevent it seizing when not in use for some time.

I haven't left it for hours to find out but I know it is on for over an hour.

BobRachet

FreeBear said:

Ayr_Rage said: Along with frost protection I believe some boilers have a feature to run the pump to prevent it seizing when not in use for some time.

I was under the impression that pump cycling didn't involve the boiler firing up.

If this Vaillant is a combi boiler, it is likely that it has been set to run in "comfort" mode - This means the boiler will fire up at regular intervals to keep the internals hot so you don't have to wait too long for hot water. Turn this "feature" off, and you save gas as well as reduced wear & tear. But it does mean you have to wait a little longer for hot water.

Would that make my heating come on though? It actually did again this morning which is the first time it's done it twice in 24 hrs.

ThisIsWeird

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?

FreeBear

BobRachet said:

Ayr_Rage said:

How long does it run for when it "randomly comes on"?

Along with frost protection I believe some boilers have a feature to run the pump to prevent it seizing when not in use for some time.

I haven't left it for hours to find out but I know it is on for over an hour.

Doesn't sound like "comfort" mode (preheating for DHW). Could be a faulty timer/thermostat, especially if the radiators are getting hot (or a small person has been fiddling with the times).

BobRachet

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.

FreeBear

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 ?

ThisIsWeird

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?

BobRachet

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.