This is a set of fairly common Polypipe controllers that interface an underfloor heating system to an existing heating boiler. There are two modules - the main one and then optional slave modules that allow extra thermostats and manifold valves to be used with multiple zones.
It's a very simple and neat arrangement that literally just plugs end to end to build up the desired number of channels. It also has a DIN rail mounting facility for use in panels.
There's a story behind this. Some elderly friends asked if I could check out their heating system as they had an issue with it. The issue turned out to be that while renovating a cupboard they had mistaken the manifold and wiring for their new underfloor heating system as being part of the old and obsolete heating system.
They laid into it with wire cutters (while it was live) stuffing the chopped wires back into the plasterboard they were sticking out from and also pushing them down under the floorboards (while still live).
The original controller in that section - the master unit shown here, was then thrown in the bin.
It was one of those "wish I hadn't got involved" moments. Their original heating engineer who installed the system was no longer living on the island and other heating maintenance companies had declined to get involved.
I had to identify the control system from the modules in use on other parts of the system, download the manual, work out what component was missing and replace the chopped cables.
Initially I just reconnected the boiler control line so that the rest of the system could control the boiler, then when the replacement module arrived I used the handy existing mounting holes to fit it, and reinstated their system to its original form.
During the research on the system I bought a few cheap modules from eBay. It seems to be a common thing that people enthusiastically buy complete kits for installing underfloor heating and then subsequently realise it's not just a case of banging down pipes and hooking up a few wires. They then sell the unwanted components on eBay at a greatly reduced price.
One of the notable design features is the use of a standard 230V AC relay with a capacitor across its coil to allow it to be actuated by multiple circuits via diodes. That effectively saved the use of a relay per channel. The rest is fundamentally a wire marshalling box with diagnostic indicators.
The terminals are reassuringly good quality rising clamp modules with a generous cable capacity.
I also got some of the thermal manifold actuators, so I'll take one apart in a video at some point.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies, miscellaneous heating components and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
It's a very simple and neat arrangement that literally just plugs end to end to build up the desired number of channels. It also has a DIN rail mounting facility for use in panels.
There's a story behind this. Some elderly friends asked if I could check out their heating system as they had an issue with it. The issue turned out to be that while renovating a cupboard they had mistaken the manifold and wiring for their new underfloor heating system as being part of the old and obsolete heating system.
They laid into it with wire cutters (while it was live) stuffing the chopped wires back into the plasterboard they were sticking out from and also pushing them down under the floorboards (while still live).
The original controller in that section - the master unit shown here, was then thrown in the bin.
It was one of those "wish I hadn't got involved" moments. Their original heating engineer who installed the system was no longer living on the island and other heating maintenance companies had declined to get involved.
I had to identify the control system from the modules in use on other parts of the system, download the manual, work out what component was missing and replace the chopped cables.
Initially I just reconnected the boiler control line so that the rest of the system could control the boiler, then when the replacement module arrived I used the handy existing mounting holes to fit it, and reinstated their system to its original form.
During the research on the system I bought a few cheap modules from eBay. It seems to be a common thing that people enthusiastically buy complete kits for installing underfloor heating and then subsequently realise it's not just a case of banging down pipes and hooking up a few wires. They then sell the unwanted components on eBay at a greatly reduced price.
One of the notable design features is the use of a standard 230V AC relay with a capacitor across its coil to allow it to be actuated by multiple circuits via diodes. That effectively saved the use of a relay per channel. The rest is fundamentally a wire marshalling box with diagnostic indicators.
The terminals are reassuringly good quality rising clamp modules with a generous cable capacity.
I also got some of the thermal manifold actuators, so I'll take one apart in a video at some point.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies, miscellaneous heating components and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
Does the master unit have an internal fuse at all? I’ve got live power going in but nothing is working!
Hi Big Clive..a bit of advice please..I have the same polypipe control unit..yesterday I noticed my room thermostats had blank screens and my fused had tripped..I've narrowed it down to the 240v feed to the unit..once connected it blows the 3amp fuse..I've disconnected the thermostats and it still trips…could it be the pump off the manifold or a faulty control unit..really unusual as my heating was switched off when it happened..only DHW was on.
Please please can you advise me.
Kind regards
Radcliffe
I have one of these in my UFH install and recently the UFH has stopped working. Nothing was changed. Just stopped working. Fuse is intact, Green lights come for Thermostats but Red LEDs for Boiler/Pump lights do not come on. Tested pump independently works fine. I have changed both Power Relays & the Capacitor. Diodes & Resistors test OK. Still does not work. I'm lost as to what's gone wrong and how to fix. Any ideas?
I have one of these in my UFH install and recently the controller has stopped working. The thermostats call for heat but the relay circuit does not switch on. I have replaced both of the power relays on the PCB and yet the problem still persists. Would my symptoms be explained by the failure of the capacitor. It doesn’t physically look blown????? TIA
Could the 'graphite" coating be just for corrosion protection? On your slave board schematic, does the series diode on the 'C 'terminal actually exist as I can't see it on the PCB photo, it wouldn't function as required if included as all you're trying to accomplish is an 'OR' function? The 'pump' relay with the capacitor is probably used because it should be an AC relay but they're much more expensive?
Brilliant – thanks for uploading
Sometimes I get amazed at how little knowledge a person with 500k house has. And importantly, how did they get so rich without intelligence.
Hi thanks for the video! Both of these two units for my underfloor heating stopped working for some reason. The engineer said that there is no electric current detected anywhere within these two units. Does it mean that I have to replace both of them? Thanks!
Have you got a video of wiring with multiple zones?
Thanks for the excellent video. I now know the fault with my UF heating is related to the heating control. Heating is turning on itself. The control (not the slave) feels hot and has a slight burn smell.
Would I need a new Control ?
I am an HVAC Tech with almost 40 years of experience.
And that was the most spectacular screw up I've heard of (that was done by a homeowner.)
If it was a contractor that would be predictable and of course when confronted the contractor would claim ignorance🤷♂️..
Suppose I had a single zone with 2/3 circuits controlled by 1 room stat would there be any need for a "control system" and actuators as discussed here? The UFH would be one zone and the radiators in the rest of the house would be another zone controlled by a different room stat.
The controller/programmer (Drayton Wiser) has 2 independently controllable CH channels and 1 HW channel. Would it be acceptable to wire the UFH zone valve and pump into the boiler and programmer in the same way that the current radiators have been done?
Currently the heating system is wired as an S-plan.
Thanks