ReplyBy your symptoms no air flow this year, furnace running can't get above 69 in house, I would think your furnace should be cycling on high limit. Secondary heat exchanger or evaporator dirty, or blower or all three. The furnace cabinet should be hot.
Regular Guest
Have a carrier 90% forced air nat gas system that was installed in 1992 by previous home owner. We've been here three years and this year no velocity coming from ducts. Can't get house ove 69 degrees here in Michigan. Replaced 4 inch filter, servcieman replaced inducer motor (it locked up), and checked system said all is ok. Blower works, flame burns. just not getting air out of the ducts. Dampers are open. Hot air duct above furnace is cool to touch. Any thoughts? Thanks
Professional Member*
By your symptoms no air flow this year, furnace running can't get above 69 in house, I would think your furnace should be cycling on high limit. Secondary heat exchanger or evaporator dirty, or blower or all three. The furnace cabinet should be hot.
Professional Member
Do you have an A/C coil above the furnace? If so it may be clogged and restricting air flow.
Regular Guest
thanks, your replies make sense, do have CA. Wouldn't 4 inch air filter trapped debris?
Professional Member*
You could have air leakage around the filter and 15+ years.Originally Posted by milender
Regular Guest
Is the cleaning normally done by the HVAC guy or one of the "duct Cleaning" companies?
Professional Member
Was the blower motor changed in the past? The rotation could be wrong.
Regular Guest
Inducer motor was replaced two weeks ago but not blower motor. Could blower connection be reversed in disassembly and reassembly? Work was done by licensed HVAC company.
Professional Member*
Are you sure the a/c and heat are not both running at the same time?
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“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
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Regular Guest
outdoor air unit is not running. If it was would it restrict air flow to ducts? I'm getting heat at the ducts, but no velocity. Thanks
Professional Member*
Yes if the coil was froze up or freezing up.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Regular Guest
Inspected A coil, no freeze up, no build up, vac'd it out anyway. No improvement. Thanks. Some one mentioned blower running backwards, mine rotates clockwise looking from the filter.
God Speed, Jim. We'll miss you - 2-26-23
Not knowing what furnace you have, or which side the air filter is on, can't tell if thats teh correct rotation or not.
When you looked to see if the coil is clean. Did you look on the side toward the blower,or the side toward the ducts.
Regular Guest
Hi thanks, looked at both on the fan side and the duct side. Held a flashight in the a coil and could see the light from the other side. Didn't have much access to check every square inch though. Model number of furnace: Carrier Weathermaker 58SXC060 Series 100 installed in 1992. FYI put a temp probe in my vents in my office at home 66 degrees in the cold air return and 82 coming out the heat vent, but no velocity not getting the house over 67 degrees. Believe it was in the teens here last night.
Regular Guest
Has the duct work come apart somewhere...no velocity in any supply?
If the unit is in the attic, is the attic warm?
Regular Guest
Hi, unit is in the basement, can see the duct work all ok, basement is cold also, normally warmer there when furnace worked. Thanks.
Professional Member
You need to call somebody.
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Regular Guest
Thanks, he's coming out tomorraw afternoon Will update as soon as.
Professional Member
Good, the air is doing one of two things... going somewhere it shouldn't, or not moving at all.... If it isnt moving at all, where is the heat all going? This is why I say it needs a first hand look.
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Regular Guest
Hate to be the boy calling wolf, but guess my "no velocity" isn't the HVAC version of 'No Velocity." Tech brought a meter with a fan on the end of the stick (sorry for the technical terms) and tested the heat vents and said that he read 200 CFM(?) + and that, I believe, 150 is minimum expected, so velocity is fine. He then tested the temp with a meter and sensor at the cold air inlet above the furnace at 67 degrees, and on the hot air side at 82 degrees. He said my problem is lack of insulation in the walls and ceiling and that the air is too cold going into the furnace. Blower is running on low of three speeds. So I guess I'm back where I started. 34 degrees outside and can't get house over 68 degrees. Again in my first explanantion we didn't have this trouble over the last three winters. So I'm at a loss. Furnace keeps running flame on. Guess I think that the heat rise should be higher then 15 degrees. Any insight on that? Thanks for all responces.
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