Correct pressures

Refrigerator & Freezer Repair
1

I repaired a leak and recharged to the correct amount on the tag (7 oz R134). Low side pressure is about -5 and high side is 140. It is cold inside but not cold enough. Low side pressure is too low, should be around +5. Not sure about high side. I am tempted to put more gas in to raise low side to correct pressure. Is there something I missed? Is the high side pressure close to correct?

2

Did you vacuum the system before recharging it? If you did , what was the pressure? Did you use a scale for recharging?

Gene.

3

[quote=Gene;499782]Did you vacuum the system before recharging it? If you did , what was the pressure? Did you use a scale for recharging?

Gene.[/quote]

Yes, I vacuumed down to -30 and flushed twice with nitrogen leaving the pump run for 3 to 4 hours. Yes, I did use a scale for recharging.

4

Did you replace the drier filter?

Does the evaporator fan work?

Can you describe more detailed how did you recharge the system?

Gene.

5

[quote=Gene;500386]Did you replace the drier filter?

Does the evaporator fan work?

Can you describe more detailed how did you recharge the system?

Gene.[/quote]

No, I did not replace the filter dryer.

Yes, the evap fan works.

I used a refrigeration scale (not a charging cylinder).

After tinkering with it for a while I believe there is a blocked line. Pretty sure it is not moisture. I am planning on changing the cap tube and filter dryer. I added a little more gas but the suction pressures always drop to 0 or below and the high side increases.

6

I once cleared out cap tube rosin by heating the tube while the compressor was running.Neat trick, the rosin just blows under high pressure and stays hard in the evaporator. You can also file open the cap tube, open it with a pin, then use nitrogen gas to blow it open.

7

Thanks, I’ll try heating the cap tube first.

8

It is very important to replace a drier filter every time when you open the system. This can be the culprit in your case.

Gene.

9

[quote=Gene;501090]It is very important to replace a drier filter every time when you open the system. This can be the culprit in your case.

Gene.[/quote]

I know I should have (according to proper procedure), but I don’t understand the reason. Is it because older used ones cannot filter moisture or acids as well? Just currious.

10

If you have a burnout, or the compressor has sucked in air, you must replace the filter/dryer. Last one I did, it was a simple bad compressor, no contamination, so I never changed it.
I understand most dryers have a micro screen that prevents particles from entering the cap tube, but in your case, maybe it is missing.

11

[quote=richappy;501557]If you have a burnout, or the compressor has sucked in air, you must replace the filter/dryer. Last one I did, it was a simple bad compressor, no contamination, so I never changed it.
I understand most dryers have a micro screen that prevents particles from entering the cap tube, but in your case, maybe it is missing.[/quote]

Thanks. I am going to change the filter and work on the cap tube. I’ll let you know how it works out.

12

[INDENT]What’s the big secret or is it that none of the internet professionals know the answer?

Here are the correct pressures from Frigidare Service Data Sheet #218758400 and these pressures work for most residential systems using R134a refrigerant @ 65*F Ambiant .

Low Side Pressure:
Cut-in = 6 to 13
Cut-out = -2 to +2

High Side Pressure: 105 - 115
Wattage: 150 - 220
Amps (Running): 1.3 - 1.8
[/INDENT]

13

This might help u
https://m.youtube.com/watch?v=e5R_lf7Tnmw