Testing Furnace and A/C

[David A. Andersen]

I want to see everyone in Arizona turn off their air conditioners when it hits 125°!

All that stuff from Carrier is about "operating" conditions. It doesn't say anything about "testing conditions". Operating conditions is a design criteria.

As they said:

The minimum outdoor operating ambient in cooling mode without additional accessories is 55 °F,

This means the equipment is not designed the way it is to operate continuously below 50° without additional components installed to modify the operational design conditions of that piece of equipment.

As for switching back and forth in the heat pump mode; what happens during the defrost cycle? It goes between heat and cooling in a split second, twice every 45 min.

Please explain that drastic change in operating temperature of the components and why it doesn't destroy the equipment after a single occurrence.

[Harry D. Vandermeulen]

Originally Posted by lkage

Thank you.


Step 4

—Operating Ambients

The minimum outdoor operating ambient in cooling mode without additional accessories is 55 °F,

and the maximum outdoor operating ambient in cooling mode is 125°F.
The maximum outdoor operating ambient in heating mode is 66°F.

If this were true my mother in law and her friends would have either frozen to death or have to replace their heat pumps yearly.

[Dan Bowers, CMI]

Two Thoughts:

To be honest I know how I do it and could care less what anybody else does. Last summer I saw a real interesting thing happen.

A "couldn't keep his hands off it buyer" kept playing with things. He was a real dumbo and the agent went along with it. I mentioned right up front, there was a cat litter box on the floor so even though I had not seen a cat / Treat the house like there is one. DO NOT leave doors open - IF you walk into the garage OR out onto the patio / SHUT the door behind you. Him and the agent kept coming in and out AND leaving doors wide open AND sure enough eventually a cat AND little minature something dog appeared and shot out an open door. By the time the inspection was over, they still had not rounded up fluffy the cat.

I had continually kept telling him to keep his hands in his pockets AND not play with stuff / He didn't think the A/C was getting cool enough fast enough, so he kept fiddling with the T-Stat - turning it on & off. I kindly explained to him that when the A/C was running and turned off - IT needed to EQUALIZE the pressures before trying to start again. About the 5th time he did that I heard a loud WHOOSH and watched black oil start running out from under the condensor (28 year old unit).

When the seller and listing agent called that night wanting to know WHY the home inspector let the dog & cat out AND broke the A/C unit AND wanted to know HOW I was gonna pay ........ I politely explained that I had watched the realtor and buyer do the deed AND offered to write a letter if these slease bags did NOT offer to pay.

The A/C unit should NOT be IMMEDIATELY recycled. You got NO idea if the unit has a delay OR not / Nor do you know if its working.

[Charley L. Bottger]

Originally Posted by dbowers

:
The A/C unit should NOT be IMMEDIATELY recycled. You got NO idea if the unit has a delay OR not / Nor do you know if its working.

Dan you and I both know the A/C needs to equalize before restarting but the thread was originally about switching from cool to heat or heat to cool which does not require a delay by the operator of the thermostat most newer units have a time delay built in.

[David A. Andersen]

There is also a device in the compressor which will turn it off in about 5 sec. if it can not start. This will go on till the pressure equalizes, and it will start.

There was something wrong with the compressor to start with. It just hadn't happened yet.

Was it capacitor oil or did the terminal block blow out of the compressor?

Better then, than later I guess.

I consider this activity "Normal Operation" as the stupid fumbling client probably turns down the t-stat and then back up every day, just to see what the temperature is set at!...

The equipment should be able to take it.
If it can't, there is a thing such as a time delay relay that should have been manufactured into the design.

Do we test garage door reversal?
That is not normal operation, but is it normal for it to reverse if the door is stuck against something.

[Dan Bowers, CMI]

UNFORTUNATELY for the dumbo inspector OR newbie inspector that does this and it BREAKS for whatever REASON, he'll be buying it. The A/C guy does this he's got parts and tools and know-how to fix it / the majority of home inspectors do not.

AND .... the A/C unit should NOT be IMMEDIATELY recycled. You got NO idea if the unit has a delay OR not / Nor do you know if its working, jumpered out OR if present defective.

[David A. Andersen]

Originally Posted by dbowers

UNFORTUNATELY for the dumbo inspector OR newbie inspector that does this and it BREAKS for whatever REASON, he'll be buying it. The A/C guy does this he's got parts and tools and know-how to fix it / the majority of home inspectors do not.

I have had many fail through the years.
Never had a single attempt to collect on it's replacement or repair.
So I don't know where that comes from...


AND .... the A/C unit should NOT be IMMEDIATELY recycled. You got NO idea if the unit has a delay OR not / Nor do you know if its working, jumpered out OR if present defective.

Isn't that we are there for? To find out?


Your not reading.
Heat Pumps cycle between heat and A/C every 45 minutes on their own!

If you try to tell me that gas heat is different then that is even more wrong. The hot heat exchanger is up stream of the A/C components and the only cold it feels is room temperature. A/C components downstream of the furnace is the same as the Heat Pump situation.

I have had to change the high limit safeties to a higher value so furnaces would stay running for the AHJ in 95F(+) weather so they would pass the install!

Heating/cooling cycling happens all the time out there. Your not going to convince me that a Home Inspector Test is going to be any different.

The only problem in testing is an A/C in winter conditions and that is not what we are talking about here.

All this talk just clouds the situation for the " dumbo inspector OR newbie inspector", as you describe them.

[Dan Bowers, CMI]

Sorry David / With a degree in HVAC I know what you're saying.

But what I said stands 100%

In KC maybe we've got a whole new breed of agent or sellers. If you did that here and a seller OR listing agent saw it AND it failed - They'd be shoving a 2x6 up your butt AND most local A/C contractors would be quite happy to help AND most home inspectors also.