Have you seen this issue with an OWB?

[hondaracer2oo4]

Oxford,

There is a discrepancy with the two diagrams. First diagram from old post shows that the cold water can either choose to go to the HX or Boiler, Then the Hot water from the HX can either go to the Zones or the Boiler. The new diagram shows that the cold water can either go to the boiler or the HX, But the hot water can only go to the boiler after it is heated. Unless I read it wrong that is what I see. Both diagrams are flawed though in design, neither would work efficiently. The Best case is for the cold water return to be pumped only through the HX heating it up to 180, then sending it to the boiler(at 180, aquastat on boiler never calls), then from the boiler to the zone manifold, then to the rest of the house, returning cold back to the HX again. That is how I would run it and the boiler would never call for heat.

 

[mingom]

Hey guys,

Thanks for the info. No hard feelings Oxford, I'm sorry this has been so frustrating and dragged out so long. Hondaracer2004, I think it might be hard to see but the cold side must cycle through the boiler then back to the hx, there is no direct connection to the hx, it only comes off the zone circulator after the burner. After reading oxfords explanation it makes sense completely, everything is completely in parallel and only works by chance, I just much not have a huge load on the boiler much of the time. I'm going to look at what it's going to take to re pipe this, it'll be a bit of work as either side of the boiler is plumbed off a premade black pipe manifold, but shouldn't be too hard. I'll get some pricing from fw webbs on a circuit setter and such also. Thanks again for the help

 

[Oxford]

Hey guys,

Thanks for the info. No hard feelings Oxford, I'm sorry this has been so frustrating and dragged out so long. Hondaracer2004, I think it might be hard to see but the cold side must cycle through the boiler then back to the hx, there is no direct connection to the hx, it only comes off the zone circulator after the burner. After reading oxfords explanation it makes sense completely, everything is completely in parallel and only works by chance, I just much not have a huge load on the boiler much of the time. I'm going to look at what it's going to take to re pipe this, it'll be a bit of work as either side of the boiler is plumbed off a premade black pipe manifold, but shouldn't be too hard. I'll get some pricing from fw webbs on a circuit setter and such also. Thanks again for the help

To show that I'm not a complete knot head, if you will pm me your address and the pipe size of your hx supply and return, I will send you the appropriate circuit setter free of charge.

 

[J1m]

To show that I'm not a complete knot head, if you will pm me your address and the pipe size of your hx supply and return, I will send you the appropriate circuit setter free of charge.

Very cool, Oxford. Circuit setter rep on the way!

 

[hondaracer2oo4]

Oxford,

That is real stand up of you to do that for mingom. Sorry that I patronized you a bit, I was just a little frustrated that you know what you are doing but couldn't seem to help mingom figure it all out. Mingom, just set up the system like I showed with the heat exchanger in series with the boiler and you will never have that propane kick on again!

 

[mingom]

Hey guys sorry its been a while. Still haven't fixed the system yet, waiting on the circuit setters and warm weather to shut down both systems. Hope all is well for everyone else.

 

[hondaracer2oo4]

No problem, hope this fixes your issue.

 

[mingom]

Hey guys, I've had issues with trying to get on the site, but I wanted to give an update and some thanks to everyone who helped (Oxford & hondarace2oo4). I've seemed to fix my issues with the OWB. I re-plumbed how it interfaces with the propane unit and also did some calculations and realized my pumps couldn't handle the pressure drop through the system and heat exchanger. I upgraded to some new Grundfos 1/2 hp circulators and it seems to be working awesome.

 

[hondaracer2oo4]

Glad you got it figured out!!!