Control Question

J Matthers_2

Need ideas on control scenario

System: IFR in Warmboard throughout, 7 zones controlled with circulators, heat source is geo water to water with 40 gal buffer tank. Tank water heated to 125*. Geo controlled by Ranco aquastat linked to buffer tank with a 10* drop from set point of 125*.

Auxiliary heat currently from Aquastat 240 fx (Tikagi) through Flatplate HX. Water heater is for DHW. Going to Munchkin M80 to handle Aux heat, backup and two new zones.

The loop through the HX is currently controlled manually by plugging in the circulator (couldn’t decide how to control it in the deep freeze last winter, first season for system).

The Geo gets behind the curve when the outside temp is at 25* and can’t maintain the 125* buffer tank temp. It will steadily drop to about 95* when the weather stays cold, and can’t catch up. The idea is to have the Geo carry the load until it reaches the no return point and then have the backup kick in, say when the buffer tank temp reaches 110* to boost the buffer tank temp back up to 125*. Easy to do with a secondary aquastat controlling the circulator on the HX until the January thaw when the outside temp jumps to a nice 65* and there is no call for heat in the house. The tank temp drops to below 110* and the Aux heat kicks on when it is not needed. Also don’t want it trying to heat during the cooling season when the Tank temp is 38*. The secondary Aquastat could be tied into the zone states to deactivate on no call.

Is this something the Vision package for the Munchkin could handle? Any other control ideas that will fully automate? Just looking for suggestions and ideas.

don_42

What If

You wire the secondary aquastat and circulator in series
with a honeywell t675 or t678 remote temperture contoller.

Set it up as a outdoor thermostat and hold it out till it drop below 25 degree outside.

Just a suggestion.