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.

 

[Russell larsen]

weak blowers in nature. Cant wait until i rid myself of mine.

 

[cantoo]

Did the single blower move enough air before you installed it to replace the Hotblast ones? I also put a furnace blower on mine and had no issues with poor air flow.

 

[Whitespider]

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.
It will get hot enough while the blower is running to trip the limit switch and switch off the firebox blower.

If the gas furnace is getting hot enough to kick the blower on... you have a back draft problem.
I'm assuming you have return air hooked up to the HotBlast??

Your HotBlast circulation blower is forcing hot air in reverse direction through the gas furnace and dumping it into the return air. That heats the gas furnace sensors, and that's why the gas furnace blower is kicking on. Than the HotBlast is sucking its own hot air back in from the (cold) air return and overheating causing the limit switch to shut down the draft blower. You need to install back draft dampers to keep the hot air from the HotBlast from flowing in reverse through the gas furnace.

Basically you have created a short loop from the HotBlast, through the gas furnace, and right back to the HotBlast.
There's only one remedy... back draft dampers between the point where the HotBlast enters the ducting and the gas furnace.
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