Where are you connecting the gauges? It sounds like you have both gages on the high pressure side. You can't hook the suction gauge to the Big line on a heatpump because that is high pressure in the heating mode. There should be another tap that says low side or low pressure, that's where you hook the suction gauge. As for adding more refrigerant, I wouldn't do that until I measure the subcooling.
If you charge it in heating unless you weigh it in you want about 10° to 15° subcooling. Then this summer you need to check the subcooling at about 95° outdoor ambient then charge it to about 10° to 15° subcooling in the cooling mode and that should be the correct charge.
Can you get the suction temperature and pressure at the compressor and can you get liquid temperature and pressure at the outdoor unit.
What kind of compressor, Scroll, Reciprocating or Rotary?
You might try shifting from heat to cool while the unit is running, you can do this by jumpering the reversing valve and removing the jumper to see if this will help and if the reversing valve is shifting.
There's several possibilities to the equalized pressure. Bad check valve, suction or discharge valves in compressor bad, reversing valve stuck in the center and metering device wide open.
I haven’t really thought about what really happens inside a reversing valve for quite a few years now but I will try to explain it in general to you the best I can.
First the reversing valve determines heat or cool, when voltage is applied to the coil it is energized, and it is in one of the modes heat or cool and when the voltage is removed it is in the other mode. Some are energized in heat and some in cool depending on manufacturer. When you energize the reversing valve, you are actually applying a voltage to a coil, creating a magnetic field to the valve, shifting a spring loaded pin, to open a pilot tube and close another pilot tube and allow the discharge pressure to flow to one end of the valve causing it to shift the valve. When you remove the voltage there is no more magnetic fields so the spring loaded pin shifts back closing that pilot tube and opens the other, shifting the valve in the other direction.
Now, if you are in heat and the big line is warm, then when you shift it to cool the big line will be cold. If this is right then the reversing valve is working and ok. That would leave the compressor or check valve. Put your hoses on the big and little lines on the unit and run the unit in cooling and see if you’re high and low pressures are different. You may have to take some plastic trash bags and put around your condenser coil to block off some air to get your head pressure up. See if you can get the head up to around 225# or more, that should keep the suction pressure above 60#, high enough that the low pressure switch won’t open and shut your unit down. If you pressures look normal in cooling then it would probably be a check valve or something bypassing the TXV.
Can you look inside the unit and make sure the low side gage / hose is going to the suction line between the compressor and the center tube on the reversing valve? That is the only place you can measure the low side pressure.
I hope this helps.
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I have the gage lines attached to the shrader valves on each of the original charging valve bodies, ie, one on the low side and one on the high side. Actually I origially had the left gage on the big tube but later swapped them and still have the same presssures on each... question is why the same pressure and yet the thing does produce heat but not as much as it should with this level of pressure.
Your questions are similar to what I was thinking. Not sure what type of compressor is in it and I have no good means of measuring the temps other than an outdoor therometer that I have... I reversed the diverter switch and tested it for operation by switching the system to a/c. The small tube did not heat up as in the ac mode (as it does in the summer) and I could not feel any hot air coming from the outdoor fan while in a/c mode ; also, I removed one leg of the switch and it did not click as it does when in the heat mode. Perhaps the switch has a spring loaded in the cylinoid core to keep the contacts open when in the a/c mode? When in the heat mode, and I pulled off one leg of the switch, it clicked and I could feel the click was good and strong and the big line heats up as it should when heating and the small tube was cold.. The hot tube is about 95 degrees and the small tube is about 50-60 degrees. Also, when pulling off the switch leg in heat mode, the sound is like it performing the defrost cycle, although, perhaps not as loud.
From this I am suspicious of the heat-a/c mode switch but not sure how to further ck it. Suggestions?
Thanks,
OK ... Progress? I lost my charge due to leaking gage line overnight... Had about 5 lbs and shut off small tube hex close valve and opened the high side to purge the remaining charge (in heat mode) into my can in a bucket of ice... captured this but have only about 1/4 tank left to recharge thesystem.... The system cut off when pressure got too low and then I recharged with what I had in the can... now I have in heat mode... 25lbs on low side and 150lbs on the high side... not the prescribed lbs.... I am also getting freeze over on the condenser coiles at the top 1/4 of the outdoor unit. I presume I need more freeon; but wonder if this will cure the freeze over condition or if my defrost circuitry also needs further testing.
PS. I think the reversing valve is operating properly.
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