Friedrich VERT-I-PAK VHA-18K75RTP, Service & Parts Manual, Page: 55 / 103

55 PB
COMPONENT TESTING
Electronic Control Board Components Identification And Testing
Front
VPAK 24K
High Pressure Switch
Back
Reversing Valve
Not Used
Not Used
High Speed
Not Used
Low Speed
Not Used
(Blue)
(Green)
Not Used
Transformer
115/230 Volts
Fuse 10 Amps
250 VAC
Transformer voltage
Selector Switch
115/230 Volts
Ensure it is set at
230VAC
Diagnostic
Servicer Module
Not Used
T-stat Terminals
1. Test for power at L1 and L2 for 208/230 VAC. (Ensure the transformer voltage selector switch is set for 230 VAC)
2. TEST THE 10 AMP/250 VAC FUSE FOR CONTINUITY.
FOR THE FOLLOWING TESTS, ENSURE THE UNIT IS IN THE APPROPRIATE SETTINGS FOR THE TEST BEING PERFORMED. ENSURE
THERE ARE NO ERROR CODES ACTIVE.
3. Testing the compressor relay and heat relays:
Test for power in and power out. If there is power in and no power out, replace the electronic control board.(208/230 to L2)
4. Testing the fan and reversing valve relays:
Test for power at the reversing valve and fan relays 1 or 3. (208/230 to L2)
5. Testing the transformer:
Test the low voltage terminal strip at:
R and C for 24 VAC
F2 and F1 for 24 VAC
D2 and D1 for 24 VAC
Test the service module connector for 5 VDC (see prior page)
Test the connectors for the thermistors for up to 5 VDC
If there is no voltage at any of the above, replace electronic control board.
6. Testing the thermistors:
Disconnect the thermistor and test for resistance value (see figure 710).
7. Testing the high pressure switch (VPAK 18K, 24K only).
Test for 24 VAC at board, if there is no voltage, replace the electronic control.
Test the pressure switch for continuity, if none, replace it (switch is normally closed).
FIGURE 713 (ECB ID AND TESTING)