Google nest thermostat control remote pump for UFH

[TimH]

Hi, we have central heating with a Google Nest Thermostat E.  It's all set up and working but now we have just had underfloor heating installed downstairs and have a pump on the manifold.  The pump should only turn on when there is heat demand.  This is separate to the existing central heating pump. Is it possible to connect a second heat link to my nest so that it can wirelessly control this pump on / off, or do I need to install a new control wire from my boiler to the manifold pump?

Thanks!

[LarisaL]

Hi there, thanks for reaching out! The Nest Thermostat E, and by extension the Heat Link, is supposed to be connected either directly to the boiler, or to the zone valves if you happen to have a multi-zoned system.
If the pump you're mentioning has the same functionality as a zone valve, then it might work, but please note that what you're suggesting isn't a configuration that was tested and that we official support. 

Many thanks, Larisa.

[TimH]

Hi Larisa, thanks for this.  I don't think it is quite the same as a zone valve. The set up you mention, as I understand it, would work similar to TRVs on rads.  You'd still need a master thermostat connected to a boiler to demand heat, then you can fine tune the temperature of rooms to be lower, or shut off earlier than the main thermostat.  However, what I need is my pump to be more like the central heating pump, always on when the heating is on.  It is actually a circulation pump that blends the return from the floor back into the flow to the floor in order to ensure that the UFH runs at a lower temperature than the flow coming from the boiler.

Basically, I think the Nest Thermastat E is designed to link to a single Heat Link, whereas I want it to link to two.

Since posting my question I have discovered a simple device called "Mains Switch RF", that is designed to wirelessly replace the control wire to a CH pump.  I'll suggest this to my plumber / electrician if installing cables proves difficult.

Thanks!

[LarisaL]

Thanks for sharing this information! If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community because I'll be locking this thread. Thanks, Larisa.