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Originally Posted by 02powerstroke

Here is the situation... Design pressures are 150/300psi with 12 degree subcooling...

Actual conditions are 92Psi liquid at a temperature of 69F. High pressure side is at around 220Psi and about 12F BELOW saturation temperature. Cooling isn't really doing much indoors and runs constantly.

Is the compressor on the way out or is there a charge issue here. Forgive me as I am fairly new to the service industry.

Thanks in advance guys

Air flow, check for blockage, blower speed every thing that has to do with air flow make sure all vent are open

Originally Posted by 02powerstroke

Fan motor doesn't have any wiggle... it is aged, but not bad... Has some rust on it...

Contactor is new, looks to have been replaced recently... I will check it anyway...

Wiring looks good, no overheating signs... I will check motor amperage after I replace the cap

I shoot the temp with my infrared of every fan motor at residential A/C customers home as I am working on their unit. Good motors run at or about 104F on a typical 80F day in PA. I've seen a few read at 145F just prior to failure. Not sure if my theory works is 100% conclusive but its helps to know what may fail in the near future.

Thank you... I will check that forum out for sure.

One more bit o advice I'd give to a new person is to visit the education forum on this site and read & watch the videos. Good stuff there. Get a digital psychrometer and learn the importance of taking the wet bulb temp of the return air entering the evap, so you can determine what your superheat should be when charging fixed metering devices. You need to know when the superheat should be 5 degrees and when it should be 30 degrees. (This is on the same system mind you).

If it has txv add r22 until you get 10 subcool or whatever the mfg says. Always (almost) check caps on a service call....and contactor.

Fan motor doesn't have any wiggle... it is aged, but not bad... Has some rust on it...

Contactor is new, looks to have been replaced recently... I will check it anyway...

Wiring looks good, no overheating signs... Unit has a TXV... I will check motor amperage after I replace the cap

Originally Posted by 02powerstroke

Yeah, pulled the cap and it's shot... Easy fix

Did you check condition of the fan motor? Any side to side wiggle on the shaft? If so, it should be changed out also. Check the contactor while in there? Take amp readings after replacing the cap and compare it to motors specs? Any wiring looking corroded, showing signs of overheating? Double wall condenser coil? A nice thick blanket between them will fool into thinking your charge is correct if it's a fixed metering device.

its amazing how things happen all at once... THanks again for everyone who responded to the thread

Yeah, pulled the cap and it's shot... Easy fix

Originally Posted by 02powerstroke

well... new twist to the story... the condensing unit fan is now stationary and the liquid line is very hot... what are the chances that the condensing unit fan locked up... its late now here and its dark out so the solution will have be implemented tomorrow... We did have some large lightening storms and heavy rains.... possibility that had something to do with it failing? Seems too coincidental almost

Keep in mind I hadn't recovered any refrigerant or charged teh system up again... it was left as it was from the most recent readings

That'll do It

If you have the old analog gauges, instead of reading pressure read the refrigerant saturation temperature where the needle crosses the R22 ring of numbers around the dial. That makes it far easier to calculate SH and SC.

Using saturation temperatures makes moving from one refrigerant to another painless.
For any PURE refrigerant

• The suction gauge tells you the saturation temperature in the evaporator.
• The head gauge tells you the saturation temperature in the condenser.

If you have non-condensables in the refrigerant, the high side gauge will read higher than the saturated temperature of the refrigerant when operating, and the low side gauge will read true. That is because the non-condensables get trapped in the condenser by the subcooled liquid refrigerant at the condenser outlet.

well... new twist to the story... the condensing unit fan is now stationary and the liquid line is very hot... what are the chances that the condensing unit fan locked up... its late now here and its dark out so the solution will have be implemented tomorrow... We did have some large lightening storms and heavy rains.... possibility that had something to do with it failing? Seems too coincidental almost

Keep in mind I hadn't recovered any refrigerant or charged teh system up again... it was left as it was from the most recent readings

sounds good... I will do that... thanks for the recommendation

Originally Posted by 02powerstroke

Thanks again for all the insight... I'm just getting started but plan on learning from this page as a great resource. I'll add some refrigerant and see how the unit performance changes.

just for learning purposes, and it will not take that much longer, but recover charge and weigh, no need to pull vacurme or add dryer is system not open, then recharge with recovered charge and any additional over and above to what mfg reccomends. And usually its x amount for up to 15' lineset then certain amount for ea addl foot. I am not big on just adding gas on a system I have never worked on before.

Thanks again for all the insight... I'm just getting started but plan on learning from this page as a great resource. I'll add some refrigerant and see how the unit performance changes.

Originally Posted by 02powerstroke

Evaporator coil

Again, I think you're overthinking.

The TXV requires a solid column of liquid to meter properly.


If it doesn't get that solid column of liquid, it does more than just lose capacity. If the column has enough vapor in it, the valve can't regulate and can cause high suction even though very little cooling is being done.

Originally Posted by 02powerstroke

Evaporator coil

wrong, be more specific.

Evaporator coil

Originally Posted by 02powerstroke

Your refrigerant is a liquid

Exactly.


And what part of the system needs liquid to operate correctly?

Indoor temp is 78F, will have to measure wet bulb. The consensing unit is a piston unit. This is an original split on a ranch that had the basement finished recently.