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fresh air return question

3K views 24 replies 5 participants last post by  fireguy 
#1 ·
I have recently installed a lennox G26 furnace in my basement. i was wondering if i should have a fresh air line from outside put into my return airplenym . This was not put in when the furnace was insatlled and i have seen some places that do this. This furnace will shutdown on high limit when it is trying to warm the house in the morning and i wonder if some fresh air would help this.
 
#2 ·
Fresh air is to make up for the exhaust going out from bath fans and drier vents. It will not keep your furnace from over heating. Gas pressure too high, under sized duct, dirt filters, dirty evap coil, dirty secondary heat exchanger are the usuall causes of over heating. Don't remember exactly but think the last G26 was made 10 years ago . Good chance there's too much dirt build up on one of the above .
 
#3 ·
This furnace will shutdown on high limit when it is trying to warm the house in the morning and i wonder if some fresh air would help this.
Sign of an oversized furnace.

Adding a fresh air intake will help to increase your heating bill.
 
#7 ·
No. You could change the duct though. Might be cheaper to buy the right sized furnace if that is the problem.
I'd start with pulling the blower assembly out and checking the secondary heat exchanger for dirt first. Next would be checking the underside of the evap coil. Maybe can get by with changing the blower motor speed to a higher setting if all is clean.
 
#10 ·
thanks for the replys

i bought it used. where is the evap coil located?
If you have A/C, it should be located in the plenum on top of the furnace.

Do a load calc, and see what size furnace you need. And then buy the right size. And sell this one. And caulk it up to a learning experience.

A proper sized furnace will save you money on your heating bill.

Just curious. How many sq ft is your house?
 
#16 · (Edited)
B.C. as in Canada? You need a 90,000 BTU unit for your house. I can heat 1800-2000 sq.ft in -40C Winnipeg with that unit. WAY oversized for BC. Sorry. May need a new inducer, circuit board etc in the near future. Better to buy the proper sized unit and get it professionally installed. In Canada gas permits/inspections are a necessity or your insurance company will have a BIG problem with you.
 
#18 ·
It is a VERY serious situation. We had a garage fire (overheated rechargable battery) in the property I grew up in. Insurance companies will go up your behind with a microscope looking for an excuse to not pay. You can also be liable if the damage spreads to the neighbors.
 
#19 ·
Change the blower speed. Instead of the yellow wire(med/low) going to the heating terminal of the control board make it the brown ( med/high) or black (high). Then check the return air temp and supply air temp with the furnace heating. Temp rise should match the name plate information.
 
#21 · (Edited)
No. But I have worked on hundreds of them and know what parts go at what age and the history of that unit (I am a Lennox dealer). You will overheat and cause the heat exchanger to fail SOON. I would need to see your ductwork but it sounds way oversized for your house and climate. I would be very concerned about liability etc, the rules are a lot more strict in Canada and there are no DIY furnace sales in big box stores etc up here for a reason. Ignorance of the law is no excuse in court.
 
#25 ·
The Carbon MonOxide can escape the vent and exit into the house. CO kills. Early warning signs can include headaches, a feeling of moisture in the house. A final sign is when you or your family die. Your gas supplier or a licensed, professional heating expert will be able to test for CO.

The fix may be a new heat exchanger or new furnace. Ask Yuri the process to hire a competent contractor. He sounds like he knows his stuff.
 
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