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Probably a standard control question.

rhl Member Posts: 100
edited July 2020 in Thermostats and Controls

I have 3 floors, and I’m doing 5 manifolds,

On 2 floors it’s just a standard zone pump setup, one manifold per floor.

I stuck my bathroom loops on its own manifold with zone valves, and they have there own thermostats.

Also my first floor is two stage floor heat + rads.

Everything piped in parallel secondary zones off a primary loop with a modcon.

Can you use a standard control relay for zone pumps and another relay for zone valves from some vendor (caleffi maybe?) and wire them as master and slave?

I saw another post on this (https://forum.heatinghelp.com/discussion/91542/zone-valves-vs-zone-pumps) and @hot_rod showed a solution, but, I called caleffi tech support and they said that it won’t work. Which left me confused.


  • hot_rod
    hot_rod Member Posts: 22,258
    sure, you can mix and match. Start by writing down the sequence of operation, what needs to happen and when. In some cases isolation relays may be needed with some t-stats or controls, especially if hest and AC are controlled by one thermostat.

    This issue give you some ideas of simple and complex control wiring with ladder diagrams.


    It's always nice to leave behind an essay and wiring diagram for custom control work. Stencils included in that idronics, available online.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream