[buffalobillpatrick]

Moble, good reasons, your pumps are low power usage.

I will describe my thermostat -> zone valve -> pump on, as some may not be familiar with this,

3-wire heat only thermostats:

24vac transformer power to thermostat:
(1) Black wire (C) = common at transformer (grounded)
(2) Red wire (Rh) = hot thermostat power

when thermostat senses a need for heat it closes an internal contact, which connects the
hot thermostat power to the
(3)White wire brings 24vac power back to energize the zone valve.

The zone valve opens in about 5 seconds allowing flow through a ball controlled internal orifice, when it is completely open an internal End Switch contact closes.

All of my zone valve End Switches are wired in parallel, so that if (any or all) are closed a Solid State relay is energized, this relay controls 120vac to the Grundfos Alpha pump.

Note: I love SSR's they last forever & don't arc contacts, when controlling 120/240vac they turn on at the ac zero crossing time, a 4ms soft start if you will.

BTW, You won't find any 24vac (old term: coil) control SSR's so use a DC controlled SSR with DC on the end switches (wall wort), or use 24vac on end switches & build or buy a little diode / resistor / capacitor rectifier for relay control input.

My Grundfos Alpha pump is set to maintain a constant pressure of 6' head (2.56 psi) no matter how many zones are "calling for heat" so that all will receive equal flow, up to 14 gpm where it maxes out power, my system never reaches max pump power.