Hot water demand but no hot water...

[Emmster]

hi,

I've a Vaillant ecoTech Plus 624 with a Drayton LP522 controller.
CH control all works like a charm, but a couple of days ago the HW failed.

The boiler shows a permanent "water demand" symbol in it's display. I literally can't get the thing to stop displaying it.

The LP522 controller indicates that, from it's perspective, all is well on the timed / advance / alwaysOn settings for HW (lights on the controller come on appropriately) but neither the boiler or motorised 2 port valve (which seems to be controlling the flow to the HW cylinder heat exchanger) operates in any way whatsoever; the boiler pump doesn't activate, the gas valve doesn't open and (i guess fairly obviously) the burner doesn't burn.

I've checked the boiler error codes but there's no problems there. I've checked the 2 port valve operation and it isn't stuck. In the interests of not-breaking-it-more-than-it-already-is i've not removed any panels on any device to look in at the wiring etc.

Any ideas as to what the problem might be?

Thanks,
Stephen

 

[stevetheplumber]

hi,

I've a Vaillant ecoTech Plus 624 with a Drayton LP522 controller.
CH control all works like a charm, but a couple of days ago the HW failed.

The boiler shows a permanent "water demand" symbol in it's display. I literally can't get the thing to stop displaying it.

The LP522 controller indicates that, from it's perspective, all is well on the timed / advance / alwaysOn settings for HW (lights on the controller come on appropriately) but neither the boiler or motorised 2 port valve (which seems to be controlling the flow to the HW cylinder heat exchanger) operates in any way whatsoever; the boiler pump doesn't activate, the gas valve doesn't open and (i guess fairly obviously) the burner doesn't burn.

I've checked the boiler error codes but there's no problems there. I've checked the 2 port valve operation and it isn't stuck. In the interests of not-breaking-it-more-than-it-already-is i've not removed any panels on any device to look in at the wiring etc.

Any ideas as to what the problem might be?

Thanks,
Stephen

you need to test wih a multi meter if it working for heating that virtually rules out boiler problems on this setup look at 2 port valve cylinder stat or clockdoes the valve open when clock is set for heating and stat turned up?
if the cylinder is a mains fed type there is a overheat stat in the cylinder stat that trips and can be reset