Heat pump air handler suddenly INCREASES air flow by double????

Old 08-24-12, 04:38 PM
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Heat pump air handler suddenly INCREASES air flow by double????

I have a 3 ton heat pump system. The heat pump unit failed. I have just had the air handler on with no power to the heat pump to get air flow while I wait for A whole new system install - including new ductwork. After a couple of days, *suddenly* the air flow increased by more than double. On the far end of home registers, where for years I had to put my hand up to the register to see if there was any air flow, now I can stand 8 feet away and feel a breeze. I'd love to know what caused that all to suddenly change. I'd love to know if 'something' was blocking the air flow which had caused the 7 year old system to never have a chance to work properly, to cause a failed capacitor a few years ago, and also to cause the entire heat pump to fail.

Please help if you can.

Old 08-26-12, 01:47 AM
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It seems that all kinds of strange things can happen in the HVAC world. From what you describe, I would suspect that you have metal fabricated/insulated ducting. I would take a guess that some of the interior insulation partially let loose and drooped into the air stream causing a partial blockage. That is not supposed to happen, but it is possible. With the fan running continuous for an extended time, the constant pressure against the insulation must have folded it back into the ducting and the airflow became close to normal again.In a properly designed system, the air velocity from any of the vents should be approximately the same. If you experience diminished air flow in the future, make sure to have the system checked out by a qualified professional.

I really can't blame the capacitor failure as a result of this problem; capacitors fail all the time, more so now that most of them are foreign made. You state that you have experienced a "complete heat pump failure". I am not sure what you mean by that; did the compressor fail, one of the coils fail, the electronics fail?

Is the duct work only seven years old, or is the mechanical parts seven years old on older duct work? Metal fabricated ducting does not wear out and there is not really a good reason to replace it unless it were to be badly moldy. A section of the ducting can be dismantled for an inspection about the loose insulation. Some companies have a robot camera they can run down the duct for an inspection. If you are now getting good airflow at all vents, it would save you considerable money to find the loose insulation and have it re-glued, assuming that it is not a mold issue.

The heat pump being seven years old has lived out about 2/3 of it's efficiency life span, and if it has had high usage, is probably not nearly as efficient as a new unit would be. If however, your energy bills have not been substantially worse than others in your area, you could re-build the failed outdoor unit and probably get another seven or more years out of it. There are still many operating units out there that are 15 to 20 years old.

The heart of your heat pump is the compressor in the outdoor condensing unit. Other than the fan motors, it is the only continuously working part of your system. From the age of your unit, I would suspect that it is probably a 10 to 12 SEER, 14 to 16 SEER and even higher are now available. If your HVAC does not get high usage; ie: running all summer and all winter, rebuilding might be right for you. If it does get very high usage, probably the new unit will save you some money on your energy bill.

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