Air conditioner problem
 

I have two heat pump Air conditioners with
Duo therm thermostats(comfort control) five buttons for each. One is acting up, one day I ran heat pump, temperature outside was in the thirtys. While one unit was blowing nice hot air the other not so hot kind of lukewarm.I was told by repair man that it was low on frion and unit has to be replaced,because thear is no easy way to ad frion.i shut the unit down for 2 days restarted it again and now work fine,can't figured it out. Temperature outside are in the forties.I wonder if that has something to do with it. I appreciate any help. Thank you.

I would be very surprised if they cannot add freon to the unit. If there is exposed copper tubing anywhere on the low side (return line to the compressor) then they can tap that line and put more gas in.

If it is low than it is possible that you got better heating with the temperature being 10 degrees warmer.

It could however be a different problem too. You would have to have someone who knows these units take a look at it. There could be some sort of a control problem.
Heat pumps are basically ari conditioners that can run in reverse(sort of).
They can move heat from outside to the inside or inside to the outside. It takes extra controls to do this, compared to a regular AC.

Get a second opinion from a tech that is certified by the manufacturer.

Good day georgiann no,
First, the heat pump does not use Freon - only the A/C side uses it. Stay away from this clown - "So called RV tech." He does not know JACK! The A/C - Heatpump combo that you have is controlled by a controller board located in the unit. Its hard to determine your root cause problem since the unit is working now. Could be a problem with communication between the 5 button thermostat, the controller board, or power. For now - "Let a sleeping dog lie" - watch it and let it run normally. If the problem arises again, get a reputable RV tech to work on it. Be cautious - as you have found out there are many "clowns" (i.e. so called RV Techs) out there that do not have the knowledge or experience even to touch a RV.
Best Regards
Dutch Master
2008 Newmar Kountry Star 3960, Spartan K2 Chassis, Cummins ISL 400HP, 2014 Chevy Captiva

Here's another fun fact. Heat pumps are designed to function in heat mode down to about 43-44 F. One of your pumps maybe in better shape but it sounds like they are both running within design specs.
Good Luck

Just to clarify a couple things. Heat pumps DO use the freon the extract heat out of the outside air and transfer it to the inside. It's basically working in the opposite direction of the air condition mode (takes hot air from inside coach and dumps it outside). If it's low on freon, it likely won't work as well in either cooling or heating mode. Now if your unit has 'heat strips', ignore all the above information.

Usually on the roof a/c's these coaches have, they are not able to add freon. Most repair places recommend replacement.

One more thing to keep in mind. Heat pumps are only effective down to the high 30's outside. As they get older, that temperature goes up. Remember, they are taking heat out of the atmosphere outside the coach and even though the air outside is cold, there is still some heat that the heat pump can absorb.

Your's might be working just fine.

+1 = very accurate.

+2. The unit is a heat pump. It can run in a cooling mode or a heating mode. It does this by changing the direction of the pressurized Freon coming out of the compressor, by way of an electromagnetically controlled manifold. With the electromagnet is charged and magnetized, the unit provides cooling to the inside, and heating to the outside. With the electromagnet de-energized, the unit provides heating to the inside and cooling to the outside. No Freon = no heat pump (no heat or cool)

X3! :thumb::D

It is really hard to determine the state of the Freon charge without connecting A/C gauges to the unit. If you can connect gauges you can add Freon.


My heat pump start loosing efficiency when the out side temperature is below 40.

Lots of correct information. HVAC repair men are used to tapping into systems to add freon as long as replacement freon is available. Some of the older flavors of freon are getting tough and expensive to find resulting in replacement of hardware.

About anything that you can get at the suction and high pressure lines you can actually put a line tap on so you can get a pressure reading on the high and low pressure sides. So, yes even if they don't have a factory type valve or tap if there is room you can add one. Refrigerators haven't had any type of tap on them for years and yet you can still add one and you can still service the compressor, line filters and such and keep them working. By the way not everything is cured by adding Freon or other refrigeration gas.

How do you add the valve without opening the system? And once opened, you have to go thru the purge and vac down process before you add Freon; we can just blow off the flush. Then, once vac'd down, you gotta put in a whole new load of Freon and oil, in the right amount and proportion. It's be more fun and economical to disconnect that old one and throw it off the roof. My mom just replaced her 15,000 btu AC (not heat pump) unit and it cost less than $1200 installed.

Thanks for Windsor Bill for the correction. Heat pumps do use Freon. I thought the combo unit used an electrical element for heat (bad assumption). But if the A/C unit is working, then shouldn't the heat pump work also? Below 45 degrees, the heat pump starts is loosing diminish operation.
Regards
Dutch Master

Wrong wrong wrong
Heat pump definitely uses refrigerant( it's not called freon technically,unless it's made by Dupont)