View Full Version : Mini Split troubleshooting

05-03-2015, 04:25 PM
Ok, I have a heat pump that I installed about 1 month ago. It has not been performing properly since installation. By not performing properly, I mean I cant keep the house over 60F even when the outside temps are 15F.

This is an 18,000btu Senville Aura mini split. I am heating one open space of 900sqft. Thermopane windows, R24 in the walls, R40 in the attic.

What I have done so far....

HVAC contractor came and recovered the unit, verified no leaks, and weighed in the label charge (67oz r410a)

- I have checked all the sensors, and all are reading proper resistance.

- I have checked the compressor windings for proper resistance.

- I have verified no bulging capacitors, burn marks or other defects on the cicuit boards.

- I have verified proper communication between indoor and outdoor unit.

What I have observed....

This is where things are really making me scratch my head.

Right now, the outdoor temp is 40F and sunny, and indoor temp is 64F.

If I put my heat pump on max temp (86F) and run the indoor fan at HIGH, I get a discharge air temp from the head unit of 95F, and a draw of 6.25 amps.

If I put my heat pump on max temp (86F) and run the indoor fan at LOW, I get a discharge air temp from the head unit of 118F, and a draw of 7.6 amps.

My question is, shouldn't the compressor be ramping up when the indoor fan is on high, and slowing down when it is on low to keep a steady discharge temp?

I am wondering if this could be a TXV issue. I had the heat pump apart and took a look and noticed it does not seem very well insulated to begin with.

I also notice when the fan is on low, and the head unit heats up past a certain amount, there is a very slight whistling from the lineset. Maybe a pinch somewhere?

Can anyone point me in the direction of what the issue might be? I know this is a cheaper unit, but I had a 12,000btu of the same model that heats better than this one, so I cant believe it is just the way it is supposed to perform. There are only two HVAC Companies in my area, and one I will not use. The other is busy servicing his own equipment and does not have time to come back and diagnose mine. He told me if I could figure out what the issue was, he would do the work.

I have a gauge set, thermometer, multimeter and a detailed service manual (not the one on their website, it is garbage) if there are any other checks that might help.

A pic of my TXV as installed http://s984.photobucket.com/user/kweagle/media/20150304_152354.jpg.html

Spec sheet for the compressor