• Murray


  • Project Request  September 9 2019
  • 38.4K
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Industry: Workshop | Automotive

R143 AC Recharge with automotive HVAC pressure measurement equipment.

2008 Honda CRV AC shuts off after about 20 minutes in traffic or when idling. Temps for engine are all within range, compressor works, relays tested and working, EMC working and senses low pressure shutoff. Belts all good.

When troubleshooting our 2008 Honda CRV we had measured the low side while recharging the AC. Using the most common AC air temp to low and high side pressure measurements we found that the two factors that make the biggest differences is the low shut off and high shut off.

At 28 psi the low shut off kicks in.

At 455 psi the high shut off kicks in.

These are both regulated by the pressure sensor that is very difficult to reach from the top and very easy from the bottom once you remove your splash guard.

We also found that the compressor will exhaust over charged or too high of pressure just after it sounds like you dropped a bag of marbles in your compressor.

On the flip side if you are too low the compressor will not start.

One of our major questions was how to jumper the compressor if you needed to add R143. The compressor seemed to come on when the engine was cold if it was below 28 psi. We used this moment to recharge the unit. Once we placed a full 12 oz can into the system we connected our pressure gauges. Now, it would be better to have the gauges connected and charge the unit but we were missing one adapter so we had to do 2 and 3 attempts with one 12 oz can. Allowing the can to stay open for about a 5 count then close the value and test the pressure.

If you start to fill your unit and hear the marbles you may have overcharged the unit and will need to purge pressure from the low side.

Once we finished with our charge we allowed the engine to run for 20 minutes monitoring the pressure gauges and adjust the pressure by purging if needed.

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