Checking Heat Pump in heating mode when its 80 degrees outside?

I never check the heating mode on a heat pump when its 80 degrees outside. **Whats your standard procedure ? **I received a call from the Realtor about the heat pump not heating, I told them back in August the cooling was limited and needed servicing.

I test them in the heat mode, never had a problem, thousands of them.

Let me ask you one simple question (do you operate a A/C unit when the inside temp is 80 degrees) it is the very same. If the unit was not cooling properly in Aug it is never going to heat properly in Dec

No, I check what is being used based on the season. I’m asking does anyone else check the heating mode (maybe the reversing valve could be bad)? Would you check the furnace while doing an inspection during the summer months?

My answer is yes I check the reversing valve in the summer always have and always will. What makes you think that one should not do it.

Yes. Why wouldn’t I/you?

I always run the furnace in the summer months, regardless of how hot it is outside.
I want to make sure it works when they need it, and its a standard part of my inspections. Of course I only run it for a short time, and then turn it off…

Charlie, do I understand you to say that on a HP head pressure is not an issue when checking the heat(RV operation) in 80 degree and above temps? Think I’m about to learn me something…

George one is condensing the refrigerant in the summer time operating the A/C unit with 80 to 110 degrees out side temp. No problems

Reverse the flow of refrigerant outside condenser becomes the evaporator inside coil becomes the condenser. Start thinking ambients temps now and the temp of the refrigerant in both coils.

Hot refrigerant gas vapor is being sent to the indoor coil at high temps well above 100 degrees. The indoor return air 70 to75 degrees passing across the coil condensing the hot vapor to a liquid that travels back to the exterior coil and enters the coil through the exterior expansion valve lowering the temp in the coil to roughly 38 to 42 degrees. Keep in mind we are still in the heat mode but its summer time the out door temp is 80 to 100+ traveling across the outdoor coil that is in the 40 degree range. The low pressure low temp vapor is gaining temp from the outside ambient 80 to 100+ degrees across the coil and from the compressor itself due to compression of the vapor

The expansion valve on the outdoor coil changes the state of the refrigerant from a high pressure liquid to a low pressure vapor. The compressor takes a suction throught the reversing valve converting the low pressure low temp vapor to a high pressure high temp vapor and contuines the cycle back to the indoor coil.

Keep in mind you are not exposing the coils to any temps or pressure that they are not rated for by the MFG during a normal heating or cooling mode.

Look on the Data plate most units have the rated pressure listed

I would state in the summer time there is no need to operate the HP in the heating mode for more than 3 or 4 minutes max simply because all you need to know is does the reversing valve operate as intended.

All I do for my inspection is ensure the reversing valve operates and I operate the aux heat to ensure it operates if its electric aux I check all electrical elements with a amp meter and if the aux is gas I operate the gas furnace from its thermostat in the emergency heat mode and do a carbon monoxide test.

Woody says Thats all folks. Shows over GEEZ I got long winded;-)

Agreed with the above post. Well stated.

Well said Charley. Agree completely.

Thanks Charlie, that was very helpful . I see what I was missing and hated disclaiming the unit when temps were not in range. Protocol changed. I appreciate the long wind, it condensed the much longer wind of my HVAC manual…:slight_smile:

Just remember one thing, If anything ever happens to the heat pump and the next day it doesn’t function and the buyer turns down the purchase offer, you were the last person to touch it and test it in the heating mode in the summer, It’s in your report. You will loose your case in any court in the United States if you are sued.

Why will you loose ? Because the seller has a copy of your report that was given to him by the buyer and it says you tested it and on that day the exterior temperature was 100 degrees Fahrenheit.

I understand you want to do the best for your client, most if not all manufactures do not advise operating a heat pump in heating mode above 70 deg’s F.

This means you will buy a new heat pump, or your liability insurance company.

ah and if it’s an R-22 system you will buy the exterior unit and the interior air handler too since they are both R-22 and it gets phased out in 2020.

Don’t get sued and if you do, make sure you are ready to win ! It’s all about legality…

I do the same as above. Many air handler cabinets I encounter, however, have the ductwork taped/plastered over the cabinet door. I will not cut these to get to the elements. In these cases i document the tape & turn on auxiliary heat to confirm that at the very least, some of them are working or not at all working.

I am interested to know your procedure & tools used for your CO2 test as I feel my testing is probably inadequate & I would like to do better. Thanks in advance!

I think about this each time I do it but feel the value I offer to my clients by testing outweighs the potential repercussions. I will review & probably change my policy if I do encounter being accused of or causing damage for testing above that temp. Until then…

I do include information in my report when I inspect units using R-22. Most of my clients don’t know about this & I don’t want them to be surprised when service cost is extremely high because of supply and demand of the refrigerant. Other times they understand the condenser is old & may need replacement soon but I don’t want them to be caught off guard because they didn’t anticipate replacing the evaporator coils as well simply because of the refrigerant change.

So your saying if the indoor temp was 100 degrees you would not start the A/C unit for fear of being sued. That is bull Shi** I would win in any court because I understand how a HP operates and its pressure temp relationship.:roll:

good advice charley!

Thanks Charley, this is great info.