Did I break it? ...Heat pump

Specific Inspection Topics Inspecting HVAC Systems
21

“failed during testing”…

Trust me, no equipment manufacturer is going to design equipment that the owner can screw with an cause damage (intentionally).

I don’t know how many people (particularly woman) that turn the thermostat up, turn the thermostat down, then turn it back up"to adjust it"!this short cycle activity is a heck of a lot more potentially damaging than turning on heat and air-conditioning in sequence. The temperature differentials are not as high as you suspect and there is no reason (other than old age) for it to fail.

Heat pumps switchover every 45 minutes.

Gas furnaces with AC are actually two separate components in one.

I’m not saying it’s not bad for the equipment because you’re stressing it and anything that you do to stress it could break it when it is beyond it’s life expectancy and physical condition…

I would rather it fail when I was testing it than getting a call from the client with a failed unit while they were moving in; " I thought you tested this thing and said it was OK?! "

22

David -

As you probably know I worked as a factory rep for an AC mfg.

AND yes rapid cycling can kill a compressor. Been in a test room with one when terminals blew AND been on roof when buyer kept rapid cycling one and blew valves. Maybe if they were brand new it might not happen BUT it did.

23

How many Inspectors inspect “Test rooms”, and how many “rapid cycle” compressors in their inspection procedure?

Never said it wouldn’t happen, just like I can’t say a garage door will never break when auto-reversal is tested (as prescribed by law in TN), but it gets tested…

“This Inspection Report does not cover operating “anything” that must be turned on or operated for inspection (because it might break).” ?

Doors, windows, lights, sinks, toilets, tubs, showers, garage door, water heater, hvac, appliances. Nor do we walk on the roof because it might leak afterwards. This goes along with all the other stuff not covered in the Inspection SOP…

Please have all lights turned on before we get there so we can see what we are doing. We wouldn’t want to blow out a light bulb…

I know this is not what you mean Dan, but someone here will turn it into this if given the chance.

As you know, my stance is that no Home Inspector should inspect the HVAC equipment.
HVAC contractors can’t seem to get it right, I would not expect a Home Inspector to either.

Had three houses this week where a Gas-N-Go-Joe added refrigerant to a unit because it was not cooling…

Think this makes a difference if you add refrigerant?

I think this soaking wet compressor has more problems than a heat / cool switch-over.
11# of refrigerant in a 7# unit.

These numbers tell the whole story.
Who knows the story?

(I know HI’s don’t use these things, but that is the point)

24

David … Holy Crapola

  1. Am I reading the meter correct / 3.5 degrees superheat??

  2. How did you get such a good pic of reallyyyyyyyyyyy CLOGGED A-coils

  3. Hope the owner doesn’t give the 1st HVAC tech a 2nd chance on his unit

25

David, does that superheat measurement mean that refrigerant may be returning to the compressor as a liquid due to the overcharge?

26

  1. That was superheat “at the compressor” NOT at the evaporator.

  2. Took it apart.

Cameron, yes and the compressor picture verifies those readings?
Accumulator was full of refrigerant. If it wasn’t a Heat Pump, the compressor would be toast!

Why? It’s a scroll compressor. Why would it fail?

Had one the following day that did in fact fail for the same reason (it was not a Heat Pump).

What about those pressures? Too high and too low (at the same time)?
Two potential issues here…

27

Does the failure happen quickly or over time?

We purchased new AC about five years ago and the first time we used it, the lines vibrated really loudly. The company came back and the guy said they had overcharged it.

I’ve always wondered if any damage was done that shortened the life of the compressor.

28

Is that because the compressor is cold due to evaporation of the refrigerant inside occurring there instead of at the a-coil?

29

It most often happens quickly.

The heat of compression and the heat of work should never allow the compressor to become this cold where it condenses water vapor from the outdoor air (especially a scroll compressor). The head of a scroll compressor gets extremely hot and actually has a high temperature overload located there in many cases.

Excessive refrigerant charge can do two things, depending and equipment design. It can flood the evaporator coil back to the compressor where it will do its damage in several ways and it can backup into the discharge line of the compressor from the condenser coil.

Though the damage often happens quickly, excessive stress on the compressor over time can also take its toll.