Valliant Eco tec combi HE - heating issue

[plumb_know]

Hi everyone,

I have an issue with Valliant eco tec combi, tenant complaining heating is coming on sometimes when programable wired room stats (danfoss) are up to temperature. Typically when i attend it is always working fine so intermittent fault. I replaced both room stats for first measure but still happening, customer sent me display on boiler & egg timer was on display.

Looking online this seems to be a pump run feature and it was doing this whilst i was on site but it didn't seem to causing the heating to warm up & the boiler was not firing whilst this was displayed on site.

At the moment i am putting it down to a sticking 2 port switch on motorise valve (as 2 zone circuit) but wondering if anyone else has come across this problem with this particular boiler and could know the cause as failing the 2 port working i am thinking it could only be PCB which as far as i am aware of you can not test for faults??

Any Help much appreciated.
Thanks

 

[Scott_D]

Is pre heat on?
Does it have an auto bypass?
Did you use the s codes to see what it was doing?

 

[Chuck]

happening, customer sent me display on boiler & egg timer was on display.

Looking online this seems to be a pump run feature and it was doing this whilst i was on site but it didn't seem to causing the heating to warm up & the boiler was not firing whilst this was displayed on site.

I suspect that the boiler was/is short-cycling due to low emitter demand and the egg timer is indicating that the boiler is waiting for it the anti-cycling delay time to run out before firing up.

Is this a new behaviour (probably a fault) or is it being reported by new tennants (probably a commisioning or installation issue)? A few more details about the system, the radiators, controls, etc. would help.

 

[Last Plumber]

Is this in the right Gas forum?

 

[centralheatking]

Is this in the right Gas forum?

well yes its only ch controls and we all know they are all intermediate tech until it all gets aligned and universal ..too many micky mouse systems trying to connect with loads of other intermediate stuff inc. smart phones etc. in a few years I might buy a decent one but not now from any outfit hive is worst
Centralheatking

 

[EvilDrPorkChop]

Sounds like MV sticking to me. Doubt it'd be boiler, when there's a demand there is a radiator on screen.

 

[plumb_know]

Controls are Danfoss programmable hard wired room stat x 2 one for each heating zone. This is a new fault, the boiler has been installed for about 4-5 years without problem as far as i am aware.

system is standard panel radiators with TRV's.

 

[SJB060685]

I cant comment on the gas side but as above have you ruled out one of the zone valves keeping end switch contacted? Being an intermittent fault is a right ball ache, especially if it's fine when you're there.

 

[Last Plumber]

well yes its only ch controls and we all know they are all intermediate tech until it all gets aligned and universal ..too many micky mouse systems trying to connect with loads of other intermediate stuff inc. smart phones etc. in a few years I might buy a decent one but not now from any outfit hive is worst
Centralheatking

I think it could be something internal to the Boiler. I didn't want to comment because it is on open forum. I have experienced this issue before. Not saying it is the same cause this time because I haven't seen it but it sounds like it might be. Worth ruling it out at least.

 

[bebelynaccessdoors]

Sounds like you are an expert. Thanks by the way!

 

[plumb_know]

Thanks, everyone

i am going there next week so will try some things out and give you an update