Underfloor heating conundrum

[Sonichedgehog]

Our builder, who did an otherwise good job, installed our polypipe underfloor heating. We have one room that runs off the radiator system with a separate pump, mixer and thermostat. Here is the problem.

When the central heating is turned on all that happens is that the water pump pushing the hot water around the radiators also pushes the water around the underfloor piping. The underfloor pump does not come on and the thermostat does not click. If I remove the thermostat and connect the live wire to the neutral the pump starts working.

I have used 3 different brands of thermostats and have checked the continuity of the wiring between the thermostat and the pump.

Why is the pump not getting a signal from the thermostat and mixing the water to get the commanded temperature?

Please help!

Thanks

 

[Ermintrude]

Picture please. What boiler is this interfaced with smells like you need a n/c two port on ufh to do volt free switching!

 

[stevetheplumber]

if you connect a live and neutral all youll get is a big bang and a blown fuse/breaker

 

[Ermintrude]

Basically chain of command

Stat&programmer

Pump runs on ufh

Boiler swings in

Switching through stat should be 240v neutral common

But switch to boiler depends on boiler

 

[tamz]

If I remove the thermostat and connect the live wire to the neutral the pump starts working.

What does that tell you then? I hope Bob the builder never touched any other electrics whilst he was in.

 

[albatross]

Our builder, who did an otherwise good job, installed our polypipe underfloor heating. We have one room that runs off the radiator system with a separate pump, mixer and thermostat. Here is the problem.

When the central heating is turned on all that happens is that the water pump pushing the hot water around the radiators also pushes the water around the underfloor piping. The underfloor pump does not come on and the thermostat does not click. If I remove the thermostat and connect the live wire to the neutral the pump starts working.

I have used 3 different brands of thermostats and have checked the continuity of the wiring between the thermostat and the pump.

Why is the pump not getting a signal from the thermostat and mixing the water to get the commanded temperature?

Please help!

Thanks

Thats what you get if you get a builder to do a heating engineers job. It's obviously piped/wired up wrong. If you connect live to neutral you will get a bang and a blown fuse. Having tried 3 thermostats with no effect common sense would say it's not the thermostats. You or your builder needs to pay a professional qualified heating engineer to correct it. Also why have you not called him back as opposed to trying to fix it yourself? Due to your comment about joining live and neutral you should not be playing with electricity as you will kill yourself.

 

[tamz]

Also why have you not called him back as opposed to trying to fix it yourself?

Perhaps sonichedgehog wants a go as Mario. Its easy :wink:

 

[Chalked]

Two port motorised valve, fitted onto the flow before the manifold will cure it.

 

[Sonichedgehog]

Whoa there guys. I have abbreviated the story considerably and used "I" where I mean "the builder" in some cases. If you knew everything then you'd all say "ok, fair enough, I understand". Contrary to what you might think this is not a cheap cost cutting job.

I understand and your frustration as professional plumbers/installers. On Monday I'll call out one of your colleagues and will get this sorted.

Thank you for for taking the time to reply.