- You have the primary circulation pump controlled by the Ecodan and then two further secondary circulation pumps (one for the radiators and another for the underfloor) - is that right?
Yes that’s correct.
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What is it that decides when the secondary circulation pumps run - is that the thermostats in each room? How are those thermostats connected to the heat pump controller?
Yes, any of the thermostats in the radiator rooms sends a signal for heat which triggers a relay switch. This will cause the main pump and radiator circulation pump to fire up.
For the UFH rooms there’s a heatmiser wiring centre which controls that side. Same as above, call for heat will fire up the main pump and ufh circulation pump.
And of course both zones calling for heat at the same time has all the pumps running.
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With multiple secondary circulation pumps you’d typically have a buffer tank or low-loss-header to provide ‘hydraulic separation’ between the circuits. If you don’t have a buffer, how are the pipes for the underfloor and radiator circuits connected to the flow and return from the heat pump? Are they just connected via tee fittings?
I’ve attached a picture of my setup. Main pump in the middle, radiator circulation below it. Ufh pump is hidden behind the wall on the left. I assume that’s a low loss header at the bottom of the setup?
