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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have an AS Freedom90 that was installed without intake

Customer Question

I have an AS Freedom90 that was installed without intake filters about 7 years ago. This year I figured out how to put a 16x20 filter in the opening and have had some ignition failures. I had a tech come out and look at it and said he cleaned my flame sensor and said the the filter install looked good. When the ignition failure occurs the furnace keeps blowing cold air even after the thermostat (old 2 wire Honeywell) is turned down. I shut off the gas and the power and wait a few minutes and it usually fires up again. It failsto light and goes on blowing cold air about every other day. Any ideas?
Submitted: 1 year ago.
Category: HVAC
Expert:  gotoman for ac replied 1 year ago.

Two thing that can cause your problem. It is going out on high limit. When you turn of the power it resets fault. 1st. If your system has air conditioning the problem is going to be the cooling coil on top of furnace. It will be stopped up from years of not using filter.. You will need to have tech clean the coil which he should have checked on 1st visit. 2nd. If you do not have Air Conditioning coil on top you possibly have a bad limit. Chances are from your info it is stopped coil. Russ

Expert:  gotoman for ac replied 1 year ago.

Great info by the way thanks. Most of time we get my furnace doesn't work. Then we start guessing. Thanks for good info. Russ

Customer: replied 1 year ago.
Single stage, heat only, no AC. I was surprised how clean the whole area inside and around the furnace was when I installed the filter (1" pleated). This morning I turned up the stat and headed downstairs to monitor start up. In less than 20 seconds the combustion blower and flame on cycle had failed and the main blower was already blowing cold air. I shut off power and gas, waited about 5 minutes and turned both back on and it started normally. After warming up the house I will leave the stat turned down and try startup after letting it cool for a couple hours.
Customer: replied 1 year ago.
After turning down the t-stat to shut off the furnace (3 hours ago) I had my wife turn it up while I timed the cycling. Combustion blower came on, after 20 seconds flame came on, after another 50 seconds main fan came on. All is working normally. I will try the same thing tomorrow morning after being off all night which seems to be the time it usually fails.
By the way my condensate pump is working and is not wired into the furnace controller.
Expert:  gotoman for ac replied 1 year ago.

If it happens again please count flashes and let me know. Russ

Customer: replied 1 year ago.
Everything has been working fine. We hope it continues.
Expert:  gotoman for ac replied 1 year ago.

Sounds good Russ