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bobphoto
Removing return and supply Duct work questions

Hey all...I'm starting a complete remodel on an 1880's foursquare this week. I've had quite a bit of experience with this in the past..and I know I may have to call in some pro advice and don't have a problem with that. I have to replace a beam and some joists..I've had an engineer over to the house so I have a plan of attack. Problem is a maze of heat ducts and cold air returns that are in the area of where I have to replace joists. There are two cold air returns that are running inside the joist spaces to the plenum..one is approx 36" wide the other is about 24". They Run about 10 feet to the intakes on the first floor. There is another 36" wide cold air return that travels opposite to the other side of the house. There are also a few supply ducts that I'll need to remove. My question is..can I remove these and have the furnace still operate safely. I'm aware it may not run efficiently but I need to keep some heat flowing while I'm working. I plan to re-install the returns and supply in a month or so and size them appropriately. The furnace is a direct vent style and is about 10 years old. The main square house is approx 24x24. Thanks much for any input.
I have an illustration..but my post count won't allow any attachments...thanks

canuk
Re: Removing return and supply Duct work questions
bobphoto wrote:

Hey all...I'm starting a complete remodel on an 1880's foursquare this week. I've had quite a bit of experience with this in the past..and I know I may have to call in some pro advice and don't have a problem with that. I have to replace a beam and some joists..I've had an engineer over to the house so I have a plan of attack. Problem is a maze of heat ducts and cold air returns that are in the area of where I have to replace joists. There are two cold air returns that are running inside the joist spaces to the plenum..one is approx 36" wide the other is about 24". They Run about 10 feet to the intakes on the first floor. There is another 36" wide cold air return that travels opposite to the other side of the house. There are also a few supply ducts that I'll need to remove. My question is..can I remove these and have the furnace still operate safely. I'm aware it may not run efficiently but I need to keep some heat flowing while I'm working. I plan to re-install the returns and supply in a month or so and size them appropriately. The furnace is a direct vent style and is about 10 years old. The main square house is approx 24x24. Thanks much for any input.
I have an illustration..but my post count won't allow any attachments...thanks

There shouldn't be any issues regarding the safe operation per se -- especially if this direct vent is both the combustion air and exhaust.
It's done regularly around these parts --- either with an existing or temporary furnace while renovations take place.

A tip --- keep alot of furnace filters on hand and change them frequent as they will get plugged with all the dust being raised during the demo and construction. Another thing would be to attach filters to the open returns which reduces the amount of dust being drawn into the return air system.

Caution -- if you plan to use any type of paint stripping chemicals or similar corrosive chemicals during the reno then there's a good chance the heat exchanger in the furnace will get damaged.
Also, the remaining ducting should be throughly cleaned after construction if they will remain in place.
Then and again --- have the furnace throughly inspected after construction to see if it survived and possibly change out all the ducting.

Hopefully this helps.:)

bobphoto
Re: Removing return and supply Duct work questions

I'm certain the exhaust is the only thing that is vented out the wall...I'll be contacting an expert to figure out the proper cold air intake and supply sizes as I will be replacing a lot of this...it's very old and has half-as&^ed asbestos work all over. Thanks much...I'll go ahead and start removing the monster ducts. :D

bobphoto
Re: Removing return and supply Duct work questions

Is there any type of filter material that's best to secure over the other cold air intake and maybe supply grates to prevent debris from entering the duct work but without severely limiting suction or blowing power?

thanks

canuk
Re: Removing return and supply Duct work questions

For the returns you can simply use a regular furnace filter which come in a variety of sizes -- 16 x 24 x1 for example --- join 2 together or cut to fit the opening.

For the supplies it's really not needed since the air is blown ( positive pressure ) not being drawn into the furnace like the return. Sure , there will be some debris that will fall into the supplies ( if they are located in the floor ) and accumulate , but they are relatively easy to vacuum or rmove the debris by hand.

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