Gas and Oil Home Heating Furnaces - A/C Maint & other questions
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07-20-01, 09:38 PM
Hi folks, looked through many of the posts & didn't see my situation.
The facts: I have a 3 ton Carrier heat pump at one end of a 2500 sf ranch, the thermistat is located on the wall of the cupboard that houses the inside unit. I had an additional 6" of insulation blown in the attic last year. The vents at the far end of the house (+/- 55') have never blown very strongly and there is a 7-10 deg temp gradient summer & winter. I had a re-occuring problem with blown low voltage fuses last year that eventually went away when I wiggled all the wires a bit; inelegant, but it worked. At the time I noticed that the motor had three wires going to the control panel for low, medium & high fan speed, low speed was installed. About a month ago I got brave (when it got hot here in Mississippi) and switched the wire to the high speed setting. It seemed to improve the temp uniformity. Lately, the unit seems to be running all the time so I checked the temp this evening & it was about 10 degrees lower than the room temp. I pulled the filter (generally changed monthly) and peered up into the units coils. Egad, what a mess. There was a heavy coating of moist dust covering almost the entire surface of the coils. It wouldn't come off readily with the shop-vac so I used a soft nylon brush to gently knock it loose & the vacuumed again. They weren't perfectly clean, but looked a lot better. Now when I check the temp, its only 6 deg lower than the room! I changed the fan speed to medium, still the same temp. Is there anything I can safely spray on the coils to loosen up the residual or am I digging myself deeper into a hole? Any tips or techniques to do this? One additional point:I haven't seen any ice build up
Thanks in advance,
Dave
The facts: I have a 3 ton Carrier heat pump at one end of a 2500 sf ranch, the thermistat is located on the wall of the cupboard that houses the inside unit. I had an additional 6" of insulation blown in the attic last year. The vents at the far end of the house (+/- 55') have never blown very strongly and there is a 7-10 deg temp gradient summer & winter. I had a re-occuring problem with blown low voltage fuses last year that eventually went away when I wiggled all the wires a bit; inelegant, but it worked. At the time I noticed that the motor had three wires going to the control panel for low, medium & high fan speed, low speed was installed. About a month ago I got brave (when it got hot here in Mississippi) and switched the wire to the high speed setting. It seemed to improve the temp uniformity. Lately, the unit seems to be running all the time so I checked the temp this evening & it was about 10 degrees lower than the room temp. I pulled the filter (generally changed monthly) and peered up into the units coils. Egad, what a mess. There was a heavy coating of moist dust covering almost the entire surface of the coils. It wouldn't come off readily with the shop-vac so I used a soft nylon brush to gently knock it loose & the vacuumed again. They weren't perfectly clean, but looked a lot better. Now when I check the temp, its only 6 deg lower than the room! I changed the fan speed to medium, still the same temp. Is there anything I can safely spray on the coils to loosen up the residual or am I digging myself deeper into a hole? Any tips or techniques to do this? One additional point:I haven't seen any ice build up
Thanks in advance,
Dave
PDF
07-21-01, 12:31 AM
It goes by a bunch of different names.Go to an HVAC supply house.Tell them you want the foaming evap coil cleaner.It will clean into the coil and actually force the embedded "stuff" out of it.You may have to spray and rinse several times until water runs clear.DO NOT FORGET safety glasses.Do not change fan speeds.Leave it on high.Take a temp reading before and after cleaning coil.With blower set on low you were getting more of a "DELTA T".With coil clean take a temp reading in low speed again.Also check blower motor for oil ports.If it has them oil the bearings.PDF