65 degree rule for R-410A central AC units?

Wow! ADD set in reading that…:smiley:
Lets try for the simple answer ok?
Should we run it or not?

You asked… :wink:

Dave you know full well how an HVAC contractor can raise the head pressure and test OR charge in cold weather if he wants to … Tarp off unit, piece of plywood over the condensor top, freon bottle in pan of warm water etc, etc.

You got the service contract in Dallas for lets say a big hospital and the HVAC unit goes down … They don’t wanta hear ITS TOO COLD

BUT that is not our home inspection boys.

Yes, you can raise the head pressure many ways so that you can keep operating.
As a matter of fact I built a head pressure controller that plugs in between the unit and my refrigerant gauges and will maintain head pressure under any outdoor air temperature. So yes it can be done.

The main point is “startup”!

This cold weather can’t start thingy is about flipping the switch and starting the compressor. That is when the potential damage can and will occur if it is going to.

HVAC contractors just like home inspectors have to make the call about the start. The preparation for a contractor would be to install a refrigerant tank heater around the compressor (or heat it with an acetylene torch) before starting.

My point is if a home inspector can’t start in cold weather because of some made-up rule, the HVAC contractor falls in the same boat. So recommending further evaluation by an HVAC contractor is basically saying “I can’t start it because it’s too cold so get someone else to do it” (when that someone else is facing the same alleged situation).

Hot here today like 108. Did I run the heat on the heat pump. NO… Why, because it is hot and you can’t tell if the unit is producing heat. Which is kinda the point…

Did I run the AC, yes, it gets hot here, everyone and their brother can tell you when the AC does not work in the summer.

In the winter if it is cold, I do not run the AC. Why, because you can not tell if it working correctly. I can also not tell you how long the unit has been on before I got there.

Now if I turned on the AC in the winter and get a call in the summer that it does not work there is no way I am telling the client " I put my hand on the refrigerant lines and it felt like it was working"… LOL Where is the upside for me?? (The hand temp check is a Delta T by the way :wink: )

As to the original poster, if the Seller said the unit was working when they sold the home, then the unit was working. It is not your problem that X months later it now does not work.

Things break. Warranty Companies just SUCK, everyone knows that, not your problem.

Brian … Good post

David … The hvac guy can do the special things you and I both discussed AND check it

So can an inspector (technically).

Well, not really.

Review of Inspection Standards (yours may vary), does not, and often **excludes **“Performance” evaluation by the HI.

This include the dreaded Delta-T controversy.

The point is Mr. BK where does a HP produce the heat while in the heat mode and what would be the incoming temp of the air passing across the coil.:wink:

Thank you for your insight Mr. Anderson.

And thank you for your insight Mr. Bowers.

Where is BK I feel like a good argument:twisted: