Yet another A/C pressure question.

[scottb]

I'm using R12.

[nhromyak]

I don't have a high pressure gauge.

I will get a fan on the rear condensor. But why are my vent temps still high?

Thanks...

[Jim Sims]

Don't have my tables with me but in general terms high side pressures over 250 psi will hamper cooling and 325 psi or greater indicates the system is overheating (lack of cooling in the condenser). Jim

[Jim Sims]

Typical high side pressures (without adjustment for altitude):

For R-12
80 F ambient 170 to 210 psi
85 F ambient 180 to 220 psi
90 F ambient 190 to 230 psi
95 F ambient 205 to 250 psi
100 F ambient 220 to 270 psi

For R-134a
70 to 80 F ambient 115 to 200 psi
80 to 90 F ambient 140 to 235 psi
90 to 100 F ambient 165 to 270 psi
100 to 110 F ambient 210 to 310 psi

[scottb]

Jim: GREAT information! Do you have a similar table for low side pressures, or do they remain somewhat constant regardless of ambient temperature and/or altitude?

Thanks much!

[Jim Sims]

Originally posted by scottb
Jim: GREAT information! Do you have a similar table for low side pressures, or do they remain somewhat constant regardless of ambient temperature and/or altitude?

Thanks much!

Typical low side pressures (not adjusted for altitude):

For R-12
32 F Evaporator temp 30 psi
36 F Evaporator temp 35 psi
42 F Evaporator temp 40 psi
48 F Evaporator temp 45 psi
53 F Evaporator temp 50 psi

For 134a
33-50 F Evaporator temp 16 to 29 psi
33-60 F Evaporator temp 19 to 39 psi
40-65 F Evaporator temp 25 to 43 psi
48-65 F Evaporator temp 37 to 51 psi