OWB not transfering heat into oil burner

[TCaldwell]

Tap on the pic, much clearer and expand

 

[maple1]

Won't that only work when the zones are flowing? Same as cuŕrent setup? I might be missing something.

 

[TCaldwell]

Possibly a small bypass circuit between the top of the boiler and zone returns with a circ and ball valve, just to keep supply water flowing through boiler

 

[TCaldwell]

How about this, bypass just past Antron air purge to zone return, probably 1/2 inch with a low flow circ and ball valve?

 

[warno]

@TCaldwell doesn't the OP need to circulate the oil boiler loop through the FPHX to maintain a higher temp in the oil boiler to keep it from firing? Or am I missing something?

 

[TCaldwell]

Yes, with the owb circ, he needs another circ on the pressureized side of the hx and also a small Oiler bypass loop that all run as long as the owb has the temp
Those 3 wood circs run 24/7 to keep the Oiler hot, when the Oiler can’t make temp, the oil boiler will kick on.
Open for ideas?

 

[warno]

Yes. That's what I'm assuming needs to happen also.

A circ on the OWB that runs to and from the FPHX. That runs 24/7. Or if batch burning, shuts off with end of cycle.

A circ on the oil boiler that runs to and from the FPHX. That runs Same as the OWB side.

Then a circ to feed the zones.

@Mahoney86 I understand the frustration you're going through. It's difficult on both ends trying to diagnose problems over the internet. I went through this all last season with my system. I know it seems like alot of running back and forth checking the same things over and over but like I said it's difficult with not being able to see it first hand.

 

[maple1]

HX is not big enough.

 

[TCaldwell]

That’s possible but we don’t know what his loads are either, aside from this do you have a opinion on the piping?

 

[maple1]

I don't think enough is known about the existing system to come up with a good suggestion. The above is a quick off the cuff thought. The oil side HX loop circ (0010?) would run whenever the wood side one does. When it is doing that, the heat would either go right to loads if a heat demand, or thru the oil boiler (backwards) to keep that hot. Or maybe split some depending how much the loads need. But not sure if it would keep the oil hot enough to stop from it cutting in, if the loads were drawing all the time. So that oil side hot out of the HX could maybe be plugged right into the side of the boiler instead of the supply piping - don't know what it has for available tappings.

(Also I think the drawing has some inaccuracies - it is zoned by circs whereas the system in question I think has one load circ [which I attempted to scribble in] & zone valves?)

But - I think the current setup, with the HX in the return line, could work simply by putting a (much) bigger HX in (and fixing its orientation while at it). That does depend though on heat load & how much time the zones spend in a heat call. IMO a 20 plate is way insufficient for anything other than a lighter DHW heating load.

(Just ask Warno )

There are no doubts lots of ways this can be done. That's why I was trying to think one step at a time through this. We seemed to have gotten way bogged down in the first simple loop/step - maybe just from temp inaccuracies.