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bakerb · Jan 29, 2008, 10:19 AM

I have a Day & Night heat pump that is about 20 years old. I've noticed in the past that when it gets cold out (near or below freezing) the unit makes a loud buzzing noise. Actually the noise starts not to loud, but over the course of a minute or two it gets louder. At the loudest point of buzzing, I hear a "purging" sound, like water rushing through a pipe.

Last night the buzzing noise was enough to wake me up. Lately it's been making these sounds even when it's a bit warmer (just below 40 degrees last night).

The heater works just fine, but I need to find out how to take care of these noises.

I did recently install a new thermostat, which I could not get to work, so I re-installed the old one. I had to extend the wires to get them to reach the new thermostat (which is now gone). I assume though that any loose wiring would cause other issues besides these buzzing/purging noises.

hvac1000 · Jan 29, 2008, 10:56 AM

I did recently install a new thermostat, which I could not get to work, so I re-installed the old one. I had to extend the wires to get them to reach the new thermostat (which is now gone). I assume though that any loose wiring would cause other issues besides these buzzing/purging noises.

This is not causing the noise.

Old age is catching up with your heat pump. It could be the compressor making the noise or the fan motor.

Contact a local HVAC professional and have them check your system.

bakerb · Feb 4, 2008, 11:48 PM

Thank you for the quick reply. How much should I expect to pay for a new compressor or fan motor, including installation? Also, would it be more worth my while (energy savings) to get an entire new heat pump (and approximately what would that cost installed)? Thank you again, Bill

hvac1000 · Feb 5, 2008, 12:27 AM

Prices are set at a local level. Get 2 to 3 estimates. Replacing a compressor in a unit that is out of warranty is not worth it in my opinion. Buy a new unit and get the extended 10 year warranty. That buys you some time before the next big expense.

bakerb · Mar 1, 2008, 11:51 AM

I found out through my paperwork from the previous owner that my heat pump is over 20 years old. I've talked with 3 contractors so far, and I'm getting prices between $5000 and $6000 (ouch!). $5000 for a Lennox (that may hang over the current concrete pad, and with no permits) and $6000 for a Trane (includes new pad if needed, and includes all permits). Is it just me, or are these prices outrageous?
Also, I keep hearing from these guys that I will save 50% or 75% of my heating/cooling bill (my house is all electric). They assume my old Day&Night heat pump is a SEER 8 or 10. The new units are 13 (Lennox) and 14 (Trane). Do these saving amounts seem correct, or are they overstating what I will save?
Thanks again,
Bill

hvac1000 · Mar 1, 2008, 12:52 PM

Yes they are over stating the savings. You would have to do a manual J and other calculations with degree days etc to be accurate on savings. That number was pulled out of someone's hat. LOL

Get other contractors to give you a bid if you are not happy with the others. This way you will see a variation of prices and it will also tell you a ball park number to work with.
Get permits and inspections that way someone else is looking at there work.
I do not recommend replacing the compressor since it is old but a fan motor is not that much. 250.00 300.00 guess. If the system is working it might be worth while for someone to take a look see.

The Hp with service might give you another year or two. One of my units is a Bryant and it was made in 1978. It is 30 years old and runs great but it has had professional service all its life.