TESTING FOR EVAPORATOR SECTION LEAKS
Many leaks that go undetected are in the Evaporator Coil. This
is because evaporator sections are cabinet contained, buttoned-up
or framed into areas that do not allow easy access. In order to
avoid time consuming labor to strip off covers, ducting, blower
cages, or the unloading of product, an easy electronic screening
method is outlined:
 The drain pipe was cut to sniff the evap section. |
1. Turn off all system power
including evaporator fan motors. 2. Pressurize system to equalization including defrosting of freezer coils. 3. Warm-up and calibrate an electronic sniffer to its highest sensitivity. 4. Locate the evaporator drain outlet or downstream trap. 5. Position the detector probe at the drain opening. (Be careful that the probe does not come in contact with any water). 6. Sniff a minimum of 10 minutes or until a leak is sensed. Recalibrate the device and test again. Two consecutive POSITIVE tests confirms an evaporator leak. Two consecutive NEGATIVE tests rules out a detectable evaporator section leak. Remember that refrigerant gas is heavier than air, and gravity will cause the gas to flow to the lowest point. If the evaporator section tests positive, we must expose the coil and spray coat ALL surfaces with BIG BLU. If the evaporator screens negative, continue on to the Condensing Unit Test. |
TESTING FOR CONDENSING SECTION LEAKS
Just as the electronic sensor was used to screen for evaporator leaks, we have devised a quick method for determining condensing section leakage.
| 1. Calibrate an electronic sniffer
to its highest sensitivity and place the probe at the
base of the unit (usually under the compressor). Unit
should be fully pressurized to equalization. 2. Cover condensing unit with a cloth tarp or bed sheet to serve as a barrier against any outside air movement and also trap refrigerant gas. Do not use a plastic material. 3. Monitor for leakage for ten (10) minutes or until a leak is sensed. Re-calibrate and test again. Two consecutive positive tests confirm condensing section leakage: Two consecutive negative tests rule out a detectable leak. 4. Use the electronic sniffer to test for leaking bellows on pressure controls. Remove the control box cover and place the probe within the housing. Cover the control tightly with a cloth barrier and monitor for ten minutes as above. 5. If the results are positive, uncover the equipment and begin spray coating with BIG BLU. If the results are negative, continue to the Suction/Liquid line leak test. |
 The cloth barrier prevents air dilution and refrigerant drift. Sensing probe is placed under the compressor. |
Page 7
