Automotive Air Conditioning Information Forum (Archives)

GM Tech on Tue August 26, 2014 3:34 PM

Year: 2011
Make:

Seems everyone is hot in the house- my big 25k btu window unit is cycling off thermal overload switch (best I can tell) pump is too hot to touch, return line from evap is warm-- I have dealt with the 134a models and the old r-22 units-- but not an R410unit---So I put a saddle valve on the big 5/8 OD return line from evaporator- and low side is pegged when unit is off, and is at best 100-110psi while running Do low side really run this high with R410?---I would guess it is lowon charge due to low side from evap is warm. My new tank of R410 come UPS tomorrow--

Can anyone quote me the low side normal pressure figure?

Oh-I just googled it and read 115-120is normal-- so I assume the static charge tank pressure will be much higher in order to charge.....

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Tue August 26, 2014 at 3:48 PM by GM Tech

Dougflas on Tue August 26, 2014 4:35 PM

R410 normal pressures are 125 ish low sside and 335 high side. Make sure the condenser coil is clean. Saddle valves leak. Charge must be introduced into low sside as liquid so use manifold to meter charge. This is probably a capilliary tube system which means critically charged. Best thing to do is recover charge, install line taps by brazing them in, and recharging system. You should install a drier into liquid line. Check the cap tube for blockage/restriction. A big problem with R134 appliances is the condenser gets blocked, pressures increase and cause oil to block cap tubes. You could be looking at same thing here.

Edited: Tue August 26, 2014 at 4:41 PM by Dougflas

wptski on Tue August 26, 2014 9:25 PM

My Santa Fe Advanced dehumidifier was charged by weight only 16oz runs just under 100psi which is lower than specs tag. Had a low side service port but I added a high side Supco line tap good for 800psi because I have zero brazing skills! R410A must be charged as a liquid. Took the full charge on the high side as a liquid after evacuation and has worked all summer perfectly.

Edited: Tue August 26, 2014 at 9:28 PM by wptski

MrBillPro on Wed August 27, 2014 8:40 AM

Quote
Originally posted by: Dougflas
R410 normal pressures are 125 ish low sside and 335 high side. Make sure the condenser coil is clean. Saddle valves leak. Charge must be introduced into low sside as liquid so use manifold to meter charge. This is probably a capilliary tube system which means critically charged. Best thing to do is recover charge, install line taps by brazing them in, and recharging system. You should install a drier into liquid line. Check the cap tube for blockage/restriction. A big problem with R134 appliances is the condenser gets blocked, pressures increase and cause oil to block cap tubes. You could be looking at same thing here.

+1 What he said, yes he is also pretty correct on the 410A pressures.

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Don't take life seriously... Its not permanent.