Hotblast 1400 circulation weak

[stoken]

I installed a Hotblast 1400 wood furnace last year. It's ducted into my gas furnace per manual instructions. The small twin blowers that came with it were not pushing enough air into the house to provide heat so I installed a full sized belt driven blower. This blower isn't moving the air as I hoped either. The only way the house really heats is when the ducting is hot enough to kick in the gas furnace blower. The furnace is making plenty of heat. It will get hot enough while the blower is running to trip the limit switch and switch off the firebox blower. It acts like something is clogged and not allowing air to go through the furnace. It doesn't seem to be forcing the air back into the return either. The gas furnace is working fine so I am sure the house ducting is fine- no leaks or anything like that. A friend has suggested removing the two eight inch ducts connecting the wood unit to the gas and replacing it with a single fourteen inch duct. Any thoughts on this? I would appreciate any ideas that you may have. Thanks.

 

[begreen]

Can you post a diagram of the installation? I'm wondering if you are getting a closed loop where the supply air from the hotblast is immediately getting pulled back into the return. If so, it may need a backdraft damper.

 

[stoken]

Thanks for the reply BeGreen. That isn't the problem. I have checked for that in the gas furnace. I would be able to feel it there if that was happening. Actually I think this last blower I installed has a problem. For some reason it isn't blowing like it was before I installed it. I have a proven one that I'm working into the system now. Hopefully it will solve the problem, but if not I'll be back! Thanks again.