Mini Split performance not what it used to be

[Tracs]

I have a 18K BTU Perfect Aire ductless mini-split system 17 seer, heat pump in my 24x30 garage.

Siding is dark gray hardie board. Walls are 2x6 R19, ceiling is blown in R50. 2 - 9x8 T16 doors, 3 small windows that are dual pane pvc sliders. Slab is insulated with 2" foam under, around, and up to the bottom of the wall.

I am positive the mini-split used to keep the garage at a constant temp while I was out there with all 32' of T5 lights on. Now when I am out there with the temp set to 72f the temp climbs up to 75-78f.

Outside temp is 90f.

Output temp of the air from the air handler is 50f with intake temp of 75f. I've read a 25 degree difference is not bad. The air handler's fan is set to high all the time.

Even in cooler weather the inside temp will creep up 5 degrees or so with the lights on. Are my 36' of T5 making that much heat?

2 years ago I was using the unit for heat in the winter (Manitoba Canada) and didn't pay attention to the snow and it froze into a block of ice. For real from the pan to almost the fan motor was a block of ice. I had to change the outdoor cooling fan motor and it worked after that. Could the compressor have been damaged?

 

[Jackfre]

Have you cleaned the interior evaporator? Also, the condensing unit, but simply cleaning the easy air filters won
t get it done. You need to clean the coil and the fan blades. Pull the entire cover off the evaporator and get a small pressure sprayer for the coil. Check the manuf specs on what is allowed. I use a NuCalgon coil cleaner I picked up at my local HVAC supplier. Cleaning the fans on these is a b**** in my not very humble opinion. Once you get it cleaned, you will be amazed at how well it operates.

 

[Tracs]

Have you cleaned the interior evaporator? Also, the condensing unit, but simply cleaning the easy air filters won
t get it done. You need to clean the coil and the fan blades. Pull the entire cover off the evaporator and get a small pressure sprayer for the coil. Check the manuf specs on what is allowed. I use a NuCalgon coil cleaner I picked up at my local HVAC supplier. Cleaning the fans on these is a b**** in my not very humble opinion. Once you get it cleaned, you will be amazed at how well it operates.

I've never cleaned the coil, I'm ashamed to say in 4 years I've never even thought about it. I will check today.

 

[Jackfre]

those small diameter curved blade fans are very efficient, but when the blades get loaded up, well, the curve is filled and the fan cannot move the spec’d air volume. Be really careful in you get a shop vac on the coil. The coil fins will deform if you look at them. I have some 5 or 6 mil plastics sheets that I tape to the wall and gather into a large plastic garbage can. Protect your electronics of course. I’ve made a spray rig out of the 1/4” irrigation tubing, a 25# pressure reducing valve. Tape the end to a thin screwdriver and you can get into the fan, carefully, to spray the fins clean. I have 4 evaps in the house and they are in need of cleaning. I didn’t get it done in the off-season and now at 106* I’m not going to touch them Good luck.

 

[Tracs]

Well I would say the filters were plugged almost solid. The coil looked good. I blew some low pressure air into it careful not to deform coils.

The fan blades have a slight dust residue. I will see how it performs with the cleaned filters before taking it apart to get to the fan blades.

It might look like mold spots on the housing but it was just super fine dust. It blew off like nothing. No mold.

 

[jjrbus]

The evaporator coils on my Daikins are virtually self cleaning, I only rinse them with distilled water once a year with a garden sprayer. The fan blades are always a mess and require removing to get them clean. Cleaning in place leaves interior gunk on the fan which throws the assembly out of balance. Not noticeable unless putting hand on unit and can feel it is out of wack.

 

[Tracs]

Satisfactory results from cleaning. It was in the 90s outside today and I was in the garage working on the car all afternoon and the wall thermometer was reading 73f and the unit was set to 72f. Temps stayed at 73f for hours inside.

 

[Tracs]

A few days later and still working well.