heating duct

[coxy]

I have oil hot air and  an owb the owb has it own radiator and duct system for about 5ft then it tees in to the oil hot air duct if I am using the oil heat will it try to force the heat back through to the owb duct and deliver no heat to the house I know there will be some heat loss and would there be any trouble if I was using the 2 at the same time like if the owb temp got down and the oil heat went on using the two blowers at the same time

[PineNut]

I have two HVAC units feeding the same duct. I have seen some set up like that and when only one is operating, the air would circulate backwards through the other one. I installed mine with a barometric damper in the return side of both of the units. This will permit the air to only flow in only one direction. That works great for me

[r.man]

Coxy if the OWB rad was in the oil duct you could use the oil furnace fan to do both. Is there a code reason in your area that this can't be done?

[thecfarm]

As r.man said,that how mine is. I don't know much about all this,that is why I had someone else do it. All that he did was put a radiator into my duct work and the oil furnace fan drives air through it. If I wanted to run my oil furnace I would be driving hot air from the oil furnace thorugh the radiator.

[r.man]

Ideally if cfarms oil furnace was firing his circulation pump for the OWB should be turned off to avoid heating bleeding oil fired heat into the OWB water. Easy enough to do with one cheap relay if the system needs to be automatic.

[thecfarm]

r.man,kinda lost me there. Which don't take much.     This is all hot air. My oil furnace has no idea what my OWB is doing,if that explains anything.    I have a separate thermostat for the OWB right beside the thermostat for the oil. We keep the oil one off. No idea if the system is right or not,but never been wanting heat. Always nice and warm.

[coxy]

Coxy if the OWB rad was in the oil duct you could use the oil furnace fan to do both. Is there a code reason in your area that this can't be done?

that's how it use to be but the oil fan was blowing 4ft of cool not cold air that was around the oil pot before it was hitting the hot rad from the owb and was loosing good heat so I built a 2x2 box and put the owb rad and blower there and got 1/2 more hotter heat  the owb rad is only 10in from the blower know

[r.man]

Cfarm if you wanted to keep the oil stat set low for emergencies in case the OWB failed while no one was there it would be a good idea to have a relay that turned off the circ pump while the oil furnace burner was firing. This would keep the OWB water from stealing large amounts of heat from the oil fired airstream but would still allow heat to bleed slightly out of the house air to the OWB to keep it or the lines from freezing. There could also be a low temp thermostat on the lines to turn off the indoor fan if the OWB water lines are cool.
Coxy did the second fan make an improvement in air temp while maintaining air flow through the ductwork?

[thecfarm]

r.man,I think I see what you mean. I just like to keep things simple. That is why I have a Heatmor,simple design.

[coxy]

Coxy did the second fan make an improvement in air temp while maintaining air flow through the ductwork?

after moving the fan and rad it made 3x more heat  my basement witch is old is cool not cold 40-50     that  air that was in between the blower and the rad in the duct was cool and would blow that on a hot rad and cool it some   but it made a huge difference once I moved it      the registers on the floor are so hot now that you don't want to step on them before they where worm      in cold weather my blower would run say 18hours a day non stop   now it comes on and off like an oil burner