Vaillant ecotect 831 problem: CH won't restart, HW is fine

Our Vaillant is 18 months old. Ecotec plus 831 (kW range is 8 - 24) (Edit: Model code corrected)
It has a draytek wireless thermostat fitted and also a mechanical timer.

HW is fine, system is pressurised around 1.8 - 2

Ive read through other forum posts recommending checking S codes and the kW setting. All are fine.
Instructions too.

The problem comes in with the CH not restarting once the timer or remote thermostat turn off the CH.

The remote receiver shows a green light when the thermostat tells it to turn on again, but the CH symbol does not return to the boiler.

If I unplug it for a few hours, it will work as soon as I set the thermo or use the override button on the receiver.
This will operate until it reches the set temp and turn it off, with the resulting problem as mentioned.

Am I missing something obvious?
Any simple solutions for me? To get warm radiators at night I have to unplug the boiler during the day so that when I come home at night it will fire up. Obviously not a good situation.
My other option is to set an unrealistic temp and have it on 24/7. Again an expensive option.

Thanks.
Pete.

Hi

Is that a Drayton RF 2 prog. stat?

Thanet.

Identical to this:

RF601


the thermostat is working fine and I've tested it, tried learning mode, etc.

Once the temp reaches thermostat's set temp, then the CH turns off but will not restart, even if I use the override on the receiver to make sure it's not a faulty start signal from the transmitter.

This is the analogue timer that is fitted:


130 analogue switch

I see I also have the model code wrong.
As it's an 8 - 24kW bolier, it's obviously and 831 range boile
http://www.vaillant.co.uk/installer...-efficiency-boilers-2/combination/ecoTEC_plus

If you link terminals 3 & 4 on the boiler it will run without the room stat to test. If it's still playing up phone vaillant as you are covered by a 2 year warranty.


HTH Sam

Thanks Sam.
I disconnected the receiver and did as you said.

Fired up straight away when set to 1 for the CH dial.

I've now set it to timer and it'll do great until tomorrow when I get some new cabling to wire in the receiver once again.

Thanks again for a speedy diagnosis technique and for saving me £££s.