Help w/ control of wood boiler w/ oil burner back up

Randy_30

The 1st stage boiler (wood in this case) should control the circ. If the Oil boiler is controlling the circ then the only time the circ will fire is when the oil fires.
I'm not sure what the Taco control is doing please explain more.

Better get a professional or divorce might be in the cards.

alang

Help w/control of wood boiler with oil burner backup

Help please:
1. I have a weill mclain oil fired hot water boiler with a 2 zone control. Zone valves are on return system of boiler. Circulator is on return side of boiler. No problems here.

I have installed a fox fire(indoor) add on boiler to my system and can not figure out how to wire the system to allow the wood boiler to be primary and the oil burner to be its backup.
Each boiler has its own thermostat. The wood boiler has a 2 function aqustat. 1 for the fan and 1 for the circulator.
The instructions have hooking the wiring for the circulator into the oil burner control box, to use 1 circulator to run the system. This pulls the water thru the wood boiler and pushes it thru the oil fired boiler to keep boiler the aquastat in the oil burner from running.

I have to disconnect the middle wire of the taco zone valves to keep the oil burner aquastat from tripping the breaker.
I want to be able to run the wood boiler with the oilboiler as backup. Say keep the thermostats 5f apart? Should I add another circulator to keep the systems independant? Can the new recirculator continue to pump thru the oil boiler circulator to keep the burner from running? How do I wire for the zone valve control? Can the zone valves be dirconnected and jacked open and the thermostat run the oil boiler?
Looking for any help here.Likely will get a pro but wanred t see if the fix is easy first. Im pretty handy and logical.
Thank you any and all for your help. Made steam now twice and the brides ready to put me in the dog house.
thanks.

Darrell_7

A simple piping scheme is to pull off the top of the oil boiler through the wood boiler and back into the bottom of the oil boiler using a dedicated virc pump without changing any controls on the oil boiler. In this scheme the wood boiler and the oil boiler are treated as separate entities and their wiring does not conflict. The wood boiler keeps the oil boiler hot enough to keep the oil boiler limits open and the oil burner idled while still allowing all of the oil boiler aquastat features and safties as well as the house zone valves and controls to operate normally. It also allows the oil burner to cycle back on without any input from you should the wood boiler go cold or not keep up with demand for any reason.

The primary boiler is which ever one is hotter.