Safety/Dump Zone

[Foz682]

Hey all,
I'm working on pairing a Kerr TW2000 to my current Kerr Saturn oil boiler. The boilers are both located in my garage, about 25' from the house. The house has 2 zones and the garage has 1. Supply and return pipes to the house are 1 ¼" with the zone valves in the house on returns. Zone valve in the garage is also on return.

I'm doing a supply to return with a circ between boilers, as the manual suggests. The wood boiler will keep the oil boiler hot and if I'm not around the oil burner will kick in.

The only thing I'm not sure about is the safety/dump zone, The diagram shows a direct run from the boiler supply, through the normally open zone valve, by-passing the normally closed zone valve. Thing is, my zone valves are on the return side...
I plan to use the garage zone as the dump.
I'm not sure if it will have the proper effect if I branch off of the return side of the wood boiler between it and the secondary circ and run it straight to the zone with the N/O valve bypassing the N/C one.
Or...
I never ever use the garage zone anyway, since the boiler emits enough heat to keep it comfortable in there, could I just replace the N/C valve with the N/O one? It, won't exactly be a direct run then though, since the water will have to flow though the oil boiler first. Although, it would't be difficult too to make it a straight shot.


Thanks

 

[maple1]

Dump zones should be above the boiler. Maybe hang some radiation for a separate dump zone?

 

[Foz682]

The zone in the garage is a large panel mounted to the wall. It is about a foot higher than the boiler. So it should work ok as the dump zone.

 

[maple1]

Might be hard to tell, until it is actually tried. For a power-out dump, usually you want more rise than that, and preferably straight up. I use the upstairs zones in my house, two baseboard setups. There's lots of up, right off the bat, about 12' worth or so. That works pretty good, but it sometimes takes a while for the flow to get itself going around the zones. Once it does though, it can heat pretty well the whole house by convection in a power outage - but I need to watch the fire quite close. I think if I didn't have that layout to start with, I might have just hung a couple of big cast iron rads right above my boiler & used those. Also, the bigger piping you can use, the better, but then you get into trying to hunt up a bigger zone valve.