Underfloor Heating not operating correctly in zones

[goody2b]

We had a combi fitted a few months ago to replace a heat pump that was incorrectly sized and fitted.

A month ago when we turned the heating on and everything seems fine , until noticed that the only way to have the ground floor ufh on, was to turn the basement ufh on. The basement ufh works independently, bu, the ground floor ufh does not

I contacted 2 electricians and they are scratching their heads and my bro who used to nee a sparky and now is trying to solve it with AI !

The single zone basement floor wiring centre is a Polypipe PB1ZM and the basement wiring centre is a WAT WFHC CB 4Z 230v MAS ANC UK , I am not sure if this is Polypipe , John Guest or another make. The problem is I can not find a wiring diagram for it, but I think the original electrician wired it different to the norm

Can anyone see if there is an obvious wire out of place/missing that would send a signal to the diverter/boiler and get the heating on the ground floor to work?

Many thanks in advance

 

[stem]

Usually when one zone relies on another being 'on' for it to operate, it is caused by a fault with a motorised valve. So in this scenario:

1. Ground floor heating turns 'on'. The ground floor motorised valve opens, but the internal microswitch inside the valve that starts the boiler has failed therefore the boiler doesn't start and nothing heats up.

2. The basement heating turns 'on' The basement floor motorised valve opens, its internal microswitch now starts the boiler, and as the ground floor valve is still open hot water will flow to the ground floor UFH as well.

My first check would be that the ground floor motorised valve microswitch is working and connected up properly.

If the control of the two zones was already installed and sequencing properly when the heat pump was connected, it's unlikely to be a wiring fault unless the zone control wiring was changed when the boiler was installed.

This also assumes that the plumbing is correct. Incorrect plumbing maybe another cause.

 

[CountryFan]

As above, are there any motorised valves installed? I can’t see any linked to the wiring center

 

[MrUFH]

Did you manage to figure it out? If not please post some photos of the motorised valves.
How are you currently turning the basement zone on. Is it with a thermostat?

 

[stem]

The OP hasn't been back to the forum since they posted the question almost a week ago.

From that I would assume that they've probably got it sorted by other means.