18 SEER Amana Heat Pump - Loud Grinding Noise on Startup
I have a < 1 year old 18 SEER Amana Heat Pump (this guy here: http://www.amana-hac.com/Home/Produc...5/Default.aspx ).
It was installed last year - end of January 2012.
For the past couple weeks after the defrost cycle it's been kicking back on with an insanely loud noise.
It wakes us up everytime this happens, which is about once an hour.
I just recorded it and posted it to youtube here (the grinding noise starts 20 seconds in):
It was nighttime so there's not much to see, but you can hear it clearly. Please can you guys take a listen and let me know if this is normal operation? My contractor seems to think there's no problem, but I can't imagine this incredibly loud noise is normal.
I really appreciate it.
Your technician can verify that the defrost cycle is terminating when it's supposed too. If a defrost cycle carries on unnecessarily, excessive pressures can cause a noisy compressor when the defrost cycle terminates. If the cycle is terminating correctly then there really isn't much that can be done. The higher seer equipment tends to carry on a bit noise wise when defrosting.
Thanks for the response crmont.
Your comment makes sense - I've noticed that as the temperature drops, the duration, volume, and overall jarring DECREASES - to the point where it does not wake us up. Which makes me think that the defrost cycle is carrying on unnecessarily at the higher temps, and is working correctly at lower temps.
It happens every 30 minutes. I timed it last night. Is there a way to control that timing? at the thermostat?
I have a VisionPro IAQ. I couldn't find an appropriate setting last night.
Thanks for the help.
The defrost cycle time is controlled by the defrost board within the heat pump itself, and your technician should be able to adjust the frequency of defrost cycles (typically every 30/60/90 min). I believe the default on Goodman/Amana is 30 min so that is likely where they left it.
Originally Posted by kmkuntz
Another reason demand defrost is preferred to time/temp method which produces unnecessary defrost cycles. Your Amana heat pump should have the "SmartShift" feature that Goodman units do, which delays the compressor start-up at defrost initiation/termination. This should be enabled from the factory according to Goodman documentation, however, so this may not be relevant.
Have your service person put defrost timer on longer interval. Most likely 30 minutes is too short. We set ours at 90 minutes. See if that helps.
Great info guys. I'll ask my service tech to increase the defrost cycle to 90 min, and ask him if the SmartShift feature is enabled and working.
Thanks for the help. Really appreciate it.
As evident by the video; snow on the ground means the timer should be on a 30 minute check. The hp had terminated defrost and was still equalizing pressure when the compressor started. That means the quiet shift function is already enabled. Good luck.
How long is the compressor off after the reversing valve is shifted? The "quietshift" timing for the compressor can be changed on the control board to delay the compressor so the pressures equalize before the compressor starts. I know the 13seer units have this on the new board and a delay kit can be added to systems with the old board. It sounded like the system was still equalizing when the compressor started and it was trying to pump liquid on startup thus the noise and when the liquid clears it quiets down.
The compressor is off for about 20 seconds after the reversing valve shifts. The delay kit that you mention - is that the DFTD-1? I read about it in another post on this forum. I'll call my service tech and see if he can increase that time a bit, either with this delay kit or (hopefully) via the board itself.
The noise has been absent since we've had much colder temps over the last couple days. Strange that it only grinds like that when the temps are 30-40.
Thanks everyone for all the responses.
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