Polypipe underfloor heating not working

[jontyking]

Complete amateur here. I had a Polypipe underfloor heating system put into a new extension 3yrs ago but the plumber who fit it is now no longer available - he's just had a career change, he didn't go out of business. It's just a single zone system connected to my main central heating system but for some reason it's no longer getting hot or even warm as far as we can tell, despite cranking the thermostat right up. We used to feel it getting warm at around 19 degrees but now nothing even at 30. The thermostat seems to respond to me turning the dial with a red LED that comes on briefly but nothing happens on the Control unit (Polypipe PB1ZM). I've replaced the batteries and when I do the LED flashes green and red a couple of times and then goes off. The only green LED on the PB1ZM control unit is the power light. The other three (valve, pump and boiler) stay red. I'm very happy to get a plumber out who knows what they're doing but wondered if it's a quick fix before I do. Seems like the thermostat might not be communicating with the control unit? Also it seems to be wired and have batteries - is this normal?

Any help very gratefully received, people with knowledge?

 

[SJB060685]

How competent are you with a multimetre? Above is a wiring diagram for said unit. I would be testing whether you have feed to and from stat in wiring centre and then to zone valve if fitted.

 

[jontyking]

View attachment 42390

How competent are you with a multimetre? Above is a wiring diagram for said unit. I would be testing whether you have feed to and from stat in wiring centre and then to zone valve if fitted.

Thanks very much for taking the time to reply. The answer is not very! I've got an electrician coming to take a look on my previous plumbers recommendation as he thinks its a communication error between the thermostat and the control unit. I've never bee that fond of the thermostat anyway as I'd rather have a programmable one so hopefully it's just that. Thanks again for taking the time to reply - much appreciated.

 

[Brambles]

Your thermostat appears to be hardwired to the control unit. Presumably it has not been configured with an RF unit (which is then hard wired to the control unit).

Polyplumb are not the best bits of kit around for controlling a UFH.

If you want to test the system without the thermostat - to confirm the problem - just link across C and 1 in the control unit and the system should fire up and feed the UFH zone. If that works I would consider getting a better thermostat - either hard wired or through an RF link.

Isolate the power before linking C and 1 - there is a 240v supply in the control unit. If in any doubt get a competent person to look at it.

 

[Brambles]

The thermostat wall unit should only have the batteries fitted if it is being used with an RF receiver.

 

[SJB060685]

Thanks very much for taking the time to reply. The answer is not very! I've got an electrician coming to take a look on my previous plumbers recommendation as he thinks its a communication error between the thermostat and the control unit. I've never bee that fond of the thermostat anyway as I'd rather have a programmable one so hopefully it's just that. Thanks again for taking the time to reply - much appreciated.

Your post has only just become visible due to you being a new user and comments need approving.
If you're not confident with a multimetre then please don't fiddle, theres no shame in that and electricity is a killer after all. Like Brambles and I have said it's most likely the thermostat, this can be confirmed either with a multimeter or linking it out with a short wire. Pass this information on to the electrician and he should have you up and running in no time if you need a new stat. Brambles here is the man when it comes to these so maybe he can advise you on a replacement.

 

[ShaunCorbs]

have you tried pushing the switch down on the room stat eg from the sun to the power eg on

 

[EvilDrPorkChop]

The pump light on the Wiring controller is on, yet theres no green light on the pump. So i'd hazard a guess that it's the pump thats gone or the Wiring centre isn't supplying 230v to the pump.

Without the pump the system won't work at all.