Boiler not responding to receiver for 2nd Zone but working for 1st. Worcester Bosch 32cdi

[abusimbel]

Hi All,

Thanks. so much in advance for any and all help and advice on this.

I have booked a boiler engineer but thought I would see if anyone had some thoughts on this.

Our heating system has two zones. Underfloor heating on the ground floor and radiators on the first floor. These zones are controlled by two dedicated wireless thermostats which interface with two receivers near the boiler. Salus is the brand.

The receivers and thermostats are working for both zones. They are communicating with each other and are sending a message to the boiler. Both receivers have their power and communication lights responding to the thermostats and both 'click' when a signal is sent from the thermostat

The boiler is only responding to one zone, however. The underfloor heating zone. Hot water is working fine and the ground floor heating zone is working fine, but from what I can tell the boiler is not responding to the signal that is being sent from the wired receiver. for the first-floor heating zone. The receiver clicks when it receivers a signal from the wireless thermostat but the boiler does not fire on. It does fire on with the ground floor underfloor heating.

The receiver was replaced with a different receiver and this did not fix the problem. This s why I think the receiver is functioning properly.

We have a Worcester Bosch Greenstar 32cdi compact condensing boiler.

It is worth noting that the power went out in the house around the same time this issue arose.

Thanks again and thanks for any and all advice!!!

 

[stem]

Usually in multizone systems they are fitted with a motorised valve, one controlling each zone. The thermostat when it switches the zone 'on', powers the valve motor and it winds open. Once the valve is fully open it then operates an internal switch and that is what fires up the boiler. Failure of the valve motor, or the internal switch can cause the symptom you describe.

If you can find the correct motorised valve it will have a manual lever on the side, if when the heating should be 'on' and the valve should be open, the lever feels loose and floppy, the valve motor has wound open, if there's some resistance it hasn't.

 

[abusimbel]

Thanks so much Stem, that is incredibly helpful! I will have a look at those valves in relation to the communication with the thermostat. I will let you know what I find shortly!

 

[abusimbel]

Thanks again Stem for your help. I thought I would post an update!

I gave the two valves a wiggle. They both seemed half loose and half with tension as if I was opening a valve. This was when the thermostat was sending a signal to the boiler...

As a follow on with the same issue...

Yesterday the first floor heating system suddenly responded to the signal from the thermostat. Could this be because I gave the valve a wiggle and it freed something up? Whatever happened, it only worked for half a day before the boiler stopped responding to the first floor heating zone again.

Perhaps this is a bad valve that is intermittently functioning?

Anyway, thank again and all the best.

 

[abusimbel]

Usually in multizone systems they are fitted with a motorised valve, one controlling each zone. The thermostat when it switches the zone 'on', powers the valve motor and it winds open. Once the valve is fully open it then operates an internal switch and that is what fires up the boiler. Failure of the valve motor, or the internal switch can cause the symptom you describe.

If you can find the correct motorised valve it will have a manual lever on the side, if when the heating should be 'on' and the valve should be open, the lever feels loose and floppy, the valve motor has wound open, if there's some resistance it hasn't.

Hi Stem, A big thank you! You were correct it was a faulty zone valve. I replaced it and now the system is running fine!

All the best!