Is this the most effecient set up for my 2 boilers?

[Luvmesomesamples]

Hello all! I have had my new pellet boiler installed for 3 month now and wanted to get the plumbers opinion on how my installer chose to plumb this. To a layman like myself t seems that the supply from the PB should nob coming into the return side of my oil boiler, and that my PB should not be using heated water as the return that never made it t my house. Is there a better way that you can see? My concern is that if I wanted to use my oil boiler to supplement on cold days like today that the super heated water from the oil boiler will be what the PB will be using as the return and will quickly exceed 200 degrees and will blow. Other than that system seems to be working OK. Couple of notes:

My DHW is wired so my PB is primary

I can adjust my Oil Boiler to fire after X amount of time if a min desired temp is not reached and it will also shut down once the max is reached. I currently set this at 2 hours and 120/140 degrees so essentially it never runs because I don't trust the set up.

Diagram attached so let me know your thoughts! Thanks!

Ben

 

[maple1]

No idea how all that is controlled - but plumbing wise it looks like it should work as long as it's controlled right.

Basically, looks like the PB keeps the oil boiler hot so the oil burner doesn't cut in, while leaving the rest of the system to function as it did before the PB was added. Sort of a series setup.

What you say about your oil boiler shutting down on max temp should also apply to the PB, so I don't know how it could overheat.

But as I say, don't know anything about the controls.

You do say it seems to be working OK?

 

[Luvmesomesamples]

Yes it work good. My only real concern was that when both systems are running the temp in my pb spikes really fast because the return for the Pb is the supply of the oil boiler. Guess I'm just overthinking things.

 

[Luvmesomesamples]

What would happen if I flipped the circ pump in my PB so the flow is the other direction? Wouldn't that make more sense or no?

 

[maple1]

Yes it work good. My only real concern was that when both systems are running the temp in my pb spikes really fast because the return for the Pb is the supply of the oil boiler. Guess I'm just overthinking things.

The oil burner shouldn't start unless there is a call for heat from the house, and the oil boiler temp is below that 120/140 point you mentioned. Is the pellet boiler not able to keep the oil boiler above that temp?

 

[Clarkbug]

I have a similar setup with my system, but with storage. Its not the most efficient, but avoids fighting pumps, keeps the oil boiler hot, and does work OK. Biggest issue I have is that it dillutes my hot water from storage with the cold return from the house, which hurts output from my fin tube on days like today.

Its a common way to pipe up systems that were connected to an OWB since they pump all the time and dont care about the return temps.

Ill be changing it for sure this spring (been saying that for a while now) as soon as I finalize my intent on a piping scheme....