Home, Workshop, Utility, Patio, Garage and Portable Heaters - Makeshift place built for furnace heater

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Bobkat230
09-28-09, 04:27 PM
In 2008 my husband bought a furnace. We live in Washington so most folks do not have A/C units, just furnaces. Our furnace is located in the garage. The old unit was pulled and the new one inserted into the same spot. It works perfectly fine however, today I found out that initially, there wasn't a place to put the filter (during install) so they "built" a place for it. That would be fine except you won't believe how this was done.

The metal ductwork box sits above the furnace and is the same width. The metal work rises up high then connects to the big insulated/padded tubes which feeds into the house.

Just above the heater and at the beginning of the metal work, there is an oblong sq. hole that was cut into the outside of the metal/silver ductwork wall. This was created as the place to insert filters.

You won't believe how you are supposed to get to it. First you have to "bend" a piece of metal that was created to cover the outside of the sq. hole. It's a long strip, tabbed about 2 inches on each end of the strip. It's about 3 inches or so wide. To remove you bend out one tab. You then slide the metal strip off which exposes the oblong square hole that was cut to accept filter changes. Insert the new filter then slide the makeshift piece of metal back over the sq. hole and bend the tab back into place.

No, there aren't any clamps. It's a "bending" situation. Yes, I know eventually, the metal tab will stress and break. Also no, the guy who installed it is not going to come back. I am certain of that. After you stop laughing, I would appreciate you answering my safety question. I am completly serious and ticked off that this happened without my knowledge. I have to remedy this but I just can't right now, this month.

My concern is safety. Aside from the access space being created crudely, is this a safety issue for us? I would appreciate you letting me know if I should not use my heater even though it works just fine. I always worry about fire. The burners are way down much, much lower than where the filter is located.


Red Maint
10-05-09, 11:46 AM
Bobkat, sorry to hear about this. Sounds like at the very least, you had an unqualified contractor.

The furnace filter access and door is typically pre fabricated or fabricated on site by a sheet metal person and installed in the RETURN air ductwork side of the furnace. Double check to make sure it is located on the return side. The return side ductwork will be cool, the supply will be hot. At the filter access door, the air should also suck in, not blow out at you.

If it is in fact located in the supply ductwork or "hot" side of the furnace it is wrong. The filter is meant to filter air entering the furnace not leaving it. It is a protection against dust and dirt building up inside the furnace and most importantly on the burners, heat exchanger, A/C coil, components and etc. It could be a fire hazard issue if it's on the supply side. I'm pretty sure you do have return ductwork since the furnace is located in your garage.

The filter slot should have a smooth square opening slightly larger than the width of the filter and a functional access door.

If you can't get the original contractor back to install it properly or correct the problem, please call another. Generally a qualified HVAC contractor can handle both the install and ductwork.