Controler Interface Advice Needed

[mtnmizer]

I have a controller question for the knowledgeable techs
here on the board.

I'm not exactly sure ifwhat I hope to
do is possible but I thought I'd ask anyway.

My heating system is a Weil Mclean PHD LP boiler
in series with a Econoburn woodboiler. My DHW is a Bradford
White hotwater tank circuit plumbed off to the side with the controls coming off the
boiler.

The user manual for the boiler warns about adjusting the
temps for the DHW function so I have left it in the default setting.

I would like to find switching gear/relays that would disconnect
the DHW circ pump & aquastat from LP boiler control
to a relay that runs off the wood boiler temp on the output side.

In other words when the woodboiler is hot the circ pump/aquastat
feeding the DHW tank is not controled via the LP boiler. This would
allow me to get DHW from wood without using any LP.

There's two wires involved, one to the circ pump and one to
the aquastat. Anyone have a suggestion on what I could use
to do this? I guessing a switch/relay and a 1/2zone relay plus a control
aquastat..?? Any suggestions would be appreciated..

 

[Nofossil]

I'm not familiar with the details of how your DHW tank is connected and controlled. If you're handy with relays, it wouldn't take too much to change it. Worst case:

#1) A 24vac DPDT relay that switches the DHW aquastat leads between the LP controller and the coil of relay #2 that controls the circ
#2) A 24vac DPDT relay that switches the circulator leads between the LP controller and 110vac line power
#3) An aquastat the activates relay #1 whenever the wood boiler is running

Probably worth sketching it out, but I think this would work fine.