Underfloor heating on an existing system

31 Oct 2018
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United Kingdom
I am looking to add wet underfloor heating in my bathroom
Actually it’s already piped in ...
I have a towel radiator in there already and I’m looking to run the underfloor pipe dork from that.
The underfloor heating would be controlled by a 2 port manifold and a separate thermostat
In essence it would not come on unless the main heating is on as it is only a top up for when the shower is used or a cold morning when the heating would be in anyway.
It will not be on independently therefore the reason for teeing off the main system but with a 2 port valve.
My question is this
1) would this be ok
2) Do I need a blender really? could I fit a trv and leave it on 3
3) can anyone suggest an appropriate combination of thermostat and 2 port manifold
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It'll be OK but not ideal, as UFH takes longer to heat up, but if it's a retrofit it should work well enough. You do need a blender, to protect the floor, floor covering, and pipework and prevent it overheating. UFH should be run at around 45ºC, your radiators will run at 70-80ºC. TRVs don't limit the water temperature, they limit air temperature. The Heatmiser Neostat is good option, and any single zone manifold kit with a Grundfos pump attached should be reasonable quality
Will I need another pump if it’s running from a combi from the existing system and not independently

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