has anyone wired a polypipe single zone master (pb1zm) there is a programable room stat with it on the diagram it says a volt free contact boiler or s/l connection boiler what does it mean by volt free contact boiler
VFC are just normally the contacts of a relay. the "volt free" term refers to the fact that there is no voltage coming from the pcb that controls the relay on the switch contact of the relay, this is so there is a degree of isolation between the two systems.
Most CH systems will have slave output relay with VFC, it means it should be wired to this. This output is switched when the boiler is on. By using it to call the UFH the house will reach temp qicker.
Volt free contacts are contacts which are not connected to a supply, they just open and close.
Some boilers require a set of dry contacts (from a thermostat, zone valve, control relay etc) to call heat, the supply in this case is provided by the boiler.
Normally there will be a zone valve & maybe a pump for the underfloor heating. The easiest way to install the electrics is to buy a single zone control pack.
Or (if you are feeling brave) you can wire it up just with a 10-way choc box in an enclosure.
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