2 Underfloor heating systems on same boiler?

[caymanbill]

Hi folks, we currently have an under floor heating system that provides heat for a side extension and radiators for the rest of the house.

This was all put in by the previous owners. We're currently looking at renovating our kitchen and adding underfloor heating to it.

Would it be possible to add this system to our current boiler, so we'd end up with 2 separate underfloor heating systems plus radiators connected back to one boiler (Worcester Bosch Greenstar 8000).

Cheers!

[LocoBlade]

Yep it's just adding another zone like another radiator zone, although you may need a low loss header or some other kind of hydraulic separation if the additional flow rate the extra zone requires exceeds what your boiler pump can provide. If they're physically close to each other you may simply be able to install a bigger manifold and add the kitchen UFH circuit to the same UFH zone as the extension

[caymanbill]

LocoBlade said:

Yep it's just adding another zone like another radiator zone, although you may need a low loss header or some other kind of hydraulic separation if the additional flow rate the extra zone requires exceeds what your boiler pump can provide. If they're physically close to each other you may simply be able to install a bigger manifold and add the kitchen UFH circuit to the same UFH zone as the extension

Thanks for the info. We recently got a new boiler installed, and as part of the install we where supposed to get some kind of smart thermostat to control our rads (the under floor heating has it's own controls).

However our plumber said it was not possible to use the smart thermostat, and that we needed to use our old fashioned orginal one. He mentioned this was something to do with us having under floor heating and radiators on the same boiler. Maybe im confusing a zones limitation for another limitation, bit confused to be honest.

[LooneyTunes]

caymanbill said:

Thanks for the info. We recently got a new boiler installed, and as part of the install we where supposed to get some kind of smart thermostat to control our rads (the under floor heating has it's own controls).

However our plumber said it was not possible to use the smart thermostat, and that we needed to use our old fashioned orginal one. He mentioned this was something to do with us having under floor heating and radiators on the same boiler. Maybe im confusing a zones limitation for another limitation, bit confused to be honest.

Have a look at the Drayton wiser system. Can definitely do hybrid UFH/rad systems.

[PhilboSE]

caymanbill said:

Thanks for the info. We recently got a new boiler installed, and as part of the install we where supposed to get some kind of smart thermostat to control our rads (the under floor heating has it's own controls).

However our plumber said it was not possible to use the smart thermostat, and that we needed to use our old fashioned orginal one. He mentioned this was something to do with us having under floor heating and radiators on the same boiler. Maybe im confusing a zones limitation for another limitation, bit confused to be honest.

I don’t see why that’s an issue. Al boilers I know have been simple devices with at most two “demand” lines (one for ch, one for hw). If either demand line goes live, they fire up and the valves sent the heat to whatever was demanding it.

So, superficially, you could have a smart stat for the rads and a different control system for the UFH, both wired in to the boiler demand line.

There may be a physical wiring issue (ie a separate feed back to the boiler from the best location for the ufh controls may not exist) but that’s surmountable.

I’d ask some more questions of him to understand the exact reason he says what he says. It might be a case of “I don’t know how / don’t want to do it” rather than “it can’t be done”.