Vaillant Turbomax ignition issue - but only in the evening

[Searcher2]

My ancient Vaillant Turbomax has been operating perfectly for the last few years but this week on Monday night I had no hot water or heating. I switched the boiler off and back on and all was fine again. The system is on a Honeywell system which switches the heating on in the morning for half and hour and evening. Every morning this week the heating has come on okay but when I return home from work the heating has not come on and there is no hot water. Switching it off and back on works every time. Prior to switching it off the info button gives S3 (ignition). Any ideas what could be causing this? It seems strange that it's only giving me an issue in the evenings... the boiler is going on and off all evening as the rooms hit temperature so the ignition is working fine after I 'reboot'. Thanks in advance.

 

[Deleted member 120897]

If it’s happening in the evening, it could be relevant or not. It all depends if there’s contributing factors. I would say you need a gas engineer.

 

[Searcher2]

If it’s happening in the evening, it could be relevant or not. It all depends if there’s contributing factors. I would say you need a gas engineer.

I will get one in but I am trying to troubleshoot ahead of that to help him seeing as I won't be able to demo the issue when he comes as it works fine when switched on and off again.. unless I leave it 'broken' until he turns up. It could be a coincidence that it only happens on the late afternoon switch on. I can't see it being to do with the Honeywell thermostat system. If it happened in the mornings too I could understand it more

 

[Deleted member 120897]

I would also agree it’s not the Honeywell system. Do you have any motorised valves at all?

 

[Searcher2]

I would also agree it’s not the Honeywell system. Do you have any motorised valves at all?

Yes. On the Honeywell system there is one remote controlled TVR. It's currently set to 6C all the time as I don't often use that room.

 

[Deleted member 120897]

Yes. On the Honeywell system there is one remote controlled TVR. It's currently set to 6C all the time as I don't often use that room.

That’s not a motorised valve, that’s a thermostatic radiator valve. A motorised valve is a 2 port/3 port valve.

 

[Searcher2]

That’s not a motorised valve, that’s a thermostatic radiator valve. A motorised valve is a 2 port/3 port valve.

Ah. In that case 'no'. It's a standard Turbomax Plus Vaillant combi boiler with single zone (all radiators fed at same time) so just uses the divertor valve.

 

[Deleted member 120897]

So yes, in that case then it could be anything from a pressure differential to the diverter not making. You could opt for a Vaillant fixed price repair, or go with an engineer familiar with Vaillants.

 

[Searcher2]

So yes, in that case then it could be anything from a pressure differential to the diverter not making. You could opt for a Vaillant fixed price repair, or go with an engineer familiar with Vaillants.

Thanks. The issue is now random. It did come on last night but went off this morning. It sounded like even though the ignition had not fired the fan was running. It's had the pressure switch and diverter changed in the past so maybe one of those again.

 

[Deleted member 120897]

Thanks. The issue is now random. It did come on last night but went off this morning. It sounded like even though the ignition had not fired the fan was running. It's had the pressure switch and diverter changed in the past so maybe one of those again.

Yes, could literally be anything on the sequence of operation. Fan running could be if the gas valve is opening then they get rid of a gas buildup.