I'm doing a DIY solar heated hydronic system and getting ready to wire the controls. I have some questions on options for the wiring interface between thermostats, 4 wire zone actuators, and circ pumps. System has 2 manifolds,one for 5 zones of in-floor, the other for 3 zones of in-wall pex at a higher temperature. Back up heat is a woodstove when solar heated tank has been depleated. Questions as follows:
1)What is the difference between zone controls (taco ZVC03) and switching relays (tacoSR502)
2)Do I need one for each manifold or,for example,could a 2 zone switching relay control both circ pumps with wires for all actuators on a manifold pig-tailed together where connected to switching relay. Is there a way to do this and only open the actuator for the thermostat that is calling for heat.
3) Can I reduce material cost and do this with a simple relay switch powered by a transformer. The sales pitch for the zone control seemed to be simplifying the wiring mess and I wondered how involved that would be. I installed a boiler years ago and I remember doing just that, on't recall any real issues.