UNvented cylinder dual thermosat question

[bigdek]

Customer wants an UNvented cylinder in place of existing vented. Currently has a dragon RF cylinder stat. No easy way to hard wire the new dual stat supplied with the cylinder. Is a dual RF thermostat available ? Cheers.

 

[bigdek]

Unvented

 

[muggles]

Never seen one, and I don't think it would comply as the sole source of temperature regulation anyway. It needs to be able to cut off the heat source in the event of an overheat. You couldn't guarantee that an RF one would do that if, for example, the batteries failed.

I've done it before on an Evohome system. Install a 2-port in the cylinder cupboard and wire it through the hard-wired dual stat, powered off a spur in the cupboard. If the overheat trips, the ZV will slam shut, cutting off the heat source (although it won't shut off the boiler of course). Use your standard wireless cylinder stat with suitable probe to trigger the boiler to heat the cylinder. I think this achieves compliance.

 

[rbranco]

Never seen one, and I don't think it would comply as the sole source of temperature regulation anyway. It needs to be able to cut off the heat source in the event of an overheat. You couldn't guarantee that an RF one would do that if, for example, the batteries failed.

I've done it before on an Evohome system. Install a 2-port in the cylinder cupboard and wire it through the hard-wired dual stat, powered off a spur in the cupboard. If the overheat trips, the ZV will slam shut, cutting off the heat source (although it won't shut off the boiler of course). Use your standard wireless cylinder stat with suitable probe to trigger the boiler to heat the cylinder. I think this achieves compliance.

Boiler would cut out on overheat flow/return temps anyway so might be OK doing it like that.