New Home Struggle - Vaillant Ecotec + Drayton Digistat

[Audronius]

Hello,

Recently moved into a new rental place, struggling with the heating equipment. I'm not a plumber or heating expert, did the troubleshoot I could think of with no success so seeking help from more knowledgeable people here.

Equipment: Vaillant EcoTec Pro 24 boiler plus Drayton Digistat+ thermostat.
Issue: the Digistat doesn't fire the boiler even with the digistat light on 'on'.

Troubleshooting:
- recommissioned the digistat with the RF panel. Works okay as the temp is displayed, once it's increased above ambient the fire command goes to the receiver which turns the green light on, can't see any issues there.
- checked that the boiler fires & heats the radiators fine when the timer handle on the boiler is set on 'on' (basically bypassing the whole thermostat).
- unlinked the digistat from the RF panel & tried the override button 2 before linking - green light comes on but boiler doesn't fire. There is a click sound once the digistat green light comes on.
- tried putting the boiler timer on all modes & doing the same. Off - doesn't fire, timer - doesn't fire, on - boiler heats the radiators indefinitely.
- tried restarting the whole system at the fuse, same results.

A link to some photos to show the situation - https://imgur.com/a/8N7m08B

Is there anything else I should check or should I go to the landlord informing that the thermostat is not communicating with the boiler?

Any help or advice is very much appreciated!

 

[ianmcd]

checked that the boiler fires & heats the radiators fine when the timer handle on the boiler is set on 'on

you have to leave this selector set to constantly on and your Drayton will control when the heating comes on and off

 

[Johnmdc]

Both the timer and stat need to be on for you to get heat.
You haven't got any on times set on your clock for it to work on the timed setting.
You have to push the little pegs in for the on times that you want.
If you set the timer to on once the stat is upto temperature the green light should go off and the boiler stop firing.

 

[Audronius]

you have to leave this selector set to constantly on and your Drayton will control when the heating comes on and off

Both the timer and stat need to be on for you to get heat.
You haven't got any on times set on your clock for it to work on the timed setting.
You have to push the little pegs in for the on times that you want.
If you set the timer to on once the stat is upto temperature the green light should go off and the boiler stop firing.

Thanks for the tips! I've now tried the below.

- Boiler heating switched to ON then Digistat temp increased to cause the green light to be on too. Then decreased the Digistat temp, green light went off - boiler still on & heating ~2 minutes later.
- Boiler powered off at the button, timer set to ON. Turn Digistat green light to on, power up the boiler .. and the rest goes exactly as above, keeps heating no matter what the Digistat light shows.
- Boiler set to ON, Digistat green light is off. Boiler starts & continues heating no matter what I adjust on the Digistat.

Using the boiler timer (peg legs):
- Digistat light set to off, boiler still starts heating when it reaches the on time.
- Digistat light set to on, boiler starts heating when it hits the time. Turn the Digistat down - boiler continues heating.

Seems there's just no communication between the Digistat & the boiler in any option I try.

 

[snb]

Are you sure the boiler is still heating when stat turned down ? The boiler has an overrun after stat satisfied which keeps the pump running for up to 5 mins.

 

[picasso]

It looks like a fairly new boiler, I wonder if they have left the 24v link in.

 

[Deleted member 267285]

Try leaving digistat off, turn heating switch on (the switch with the timer) if boiler fires up for heating then as per @picasso the 24v link will likely to be left in(quite common).

 

[picasso]

You have the hot water preheat switched on as well (the C on the display means preheat on) so the boiler will run to keep its self warm but not usually for 2 minutes, you could try turning it off (in the instruction) and see if it sorts the problem.

 

[Audronius]

Are you sure the boiler is still heating when stat turned down ? The boiler has an overrun after stat satisfied which keeps the pump running for up to 5 mins.

It looks like a fairly new boiler, I wonder if they have left the 24v link in.

You have the hot water preheat switched on as well (the C on the display means preheat on) so the boiler will run to keep its self warm but not usually for 2 minutes, you could try turning it off (in the instruction) and see if it sorts the problem.

Try leaving digistat off, turn heating switch on (the switch with the timer) if boiler fires up for heating then as per @picasso the 24v link will likely to be left in(quite common).

Thanks guys. Tried some more things based off this, no luck.
Comfort (preheat water) mode off.
Digistat off, boiler on timer mode - starts heating once the timer hits. Then raised the digistat to be on, left it for 5 mins. Turned digistat off, 5+ mins later boiler still heating. It only stops heating once the timer on the boiler itself runs out.

So in the end the same thing - boiler works okay and the digistat seems to function as it should but there's just no communication between the two at all.
I'll reach out to the landlord, this thread should at least help as a guide on the things I've tried if they send in a specialist to check this.

 

[ianmcd]

as others have said the low voltage link has been left in the boiler