TROUBLESHOOTING TOUCH TEST CHART: TO SERVICE REVERSING VALVES
NORMAL FUNCTION OF VALVE
| DISCHARGE Compressorfrom | SUCTION | Compressorto | toTubeINSIDE COIL | toTube | COIL | LEFT | CapillaryTube | RIGHT | CapillaryTube | NOTES: |
| ** WARMER THAN VALVE BODY | ||||||||||
VALVE | TUBE | TUBE |
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| OUTSIDE |
| Pilot |
| Pilot |
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OPERATING | * TEMPERATURE OF VALVE BODY | |||||||||
CONDITION |
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| 1 | 2 | 3 | 4 | 5 | 6 | POSSIBLE CAUSES | CORRECTIONS | ||
Normal Cooling | Hot | Cool | Cool | Hot | *TVB | TVB | ||||
as (2) | as (1) | |||||||||
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Normal Heating | Hot | Cool | Hot | Cool | *TVB | TVB | ||||
as (1) | as (2) | |||||||||
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| MALFUNCTION OF VALVE |
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| Check Electrical circuit and coil |
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| No voltage to coil. | Repair electrical circuit. | ||||
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| Defective coil. | Replace coil. | |||||
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| Check refrigeration charge |
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| Low charge. | Repair leak, recharge system. | |||
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| Pressure differential too high. | Recheck system. | ||||
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Valve will not |
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| Deenergize solenoid, raise head pressure, | ||
shift from cool |
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| reenergize solenoid to break dirt loose. | ||
Hot | Cool | Cool, | Hot, | *TVB | Hot | Pilot valve okay. Dirt in one bleeder hole. | If unsuccessful, remove valve, wash | |||
to heat. | as (2) | as (1) | out. Check on air before installing. If no | |||||||
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| movement, replace valve, add strainer to | |
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| discharge tube, mount valve horizontally. | |
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| Stop unit. After pressures equalize, restart | |
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| Piston cup leak | with solenoid energized. If valve shifts, | |||||||
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| reattempt with compressor running. If still | ||||||||
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| no shift, replace valve. | |
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| Hot | Cool | Cool, | Hot, | *TVB | *TVB | Clogged pilot tubes. | Raise head pressure, operate solenoid to | |
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| as (2) | as (1) | free. If still no shift, replace valve. | ||||||
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Valve will not |
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| Raise head pressure, operate solenoid | ||
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| Cool, | Hot, |
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| Both ports of pilot open. (Back seat port | to free | |||
shift from cool | Hot | Cool | Hot | Hot | partially clogged port. If still no shift, | |||||
as (2) | as (1) | did not close). | ||||||||
to heat. |
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| replace | ||
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| valve. | |||
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| Warm | Cool | Cool, | Hot, | *TVB | Warm | Defective Compressor. | Replace compressor | |
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| Not enough pressure differential at start | Check unit for correct operating pressures | |
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| Hot | Warm | Warm | Hot | *TVB | Hot | of stroke or not enough fl ow to maintain | and charge. Raise head pressure. If no | |
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| pressure differential. | shift, use valve with smaller port. | |
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| Body damage. | Replace valve | |||||||
Starts to shift |
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Hot | Warm | Warm | Hot | Hot | Hot | Both ports of pilot open. | Raise head pressure, operate solenoid. If | |||
but does not |
| no shift, use valve with smaller ports. | ||||||||
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complete | Hot | Hot | Hot | Hot | *TVB | Hot | Body damage. | Replace valve | ||
reversal. | Valve hung up at | Raise head pressure, operate solenoid. If | ||||||||
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| volume of compressor not suffi cient to | no shift, use valve with smaller ports. | |||||||
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| maintain reversal. | ||
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| Raise head pressure, operate solenoid. | |
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| Hot | Hot | Hot | Hot | Hot | Hot | Both ports of pilot open. | If no | |
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| shift, replace valve. | |
Apparent | Hot | Cool | Hot, | Cool, | *TVB | *TVB | Piston needle on end of slide leaking. | Operate valve several times, then recheck. | ||
as (1) | as (2) | If excessive leak, replace valve. | ||||||||
leap in heat- |
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| Hot, | Cool, |
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| Operate valve several times, then recheck. | |||
ing. | Hot | Cool | **WVB | **WVB | Pilot needle and piston needle leaking. | |||||
as (1) | as (2) | If excessive leak, replace valve. | ||||||||
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| Hot | Cool | Hot, | Cool, | *TVB | *TVB | Pressure differential too high. | Stop unit. Will reverse during equalization | |
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| as (1) | as (2) | period. Recheck system | ||||||
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| Clogged pilot tube. | Raise head pressure, operate solenoid to | |||||||
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| free dirt. If still no shift, replace valve. | ||||||||
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| Raise head pressure, operate solenoid. | |
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| Hot, | Cool, |
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| Remove valve and wash out. Check on air | |
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| Hot | Cool | Hot | *TVB | Dirt in bleeder hole. | before reinstalling, if no movement, replace | |||
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| as (1) | as (2) | |||||||
Will not shift |
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| valve. Add strainer to discharge tube. | ||||
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| Mount valve horizontally. | |||
from heat to |
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| Stop unit. After pressures equalize, restart | |||
cool. |
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| Hot, | Cool, |
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| with solenoid deenergized. If valve shifts, | |||
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| Hot | Cool | Hot | *TVB | Piston cup leak. | reattempt with compressor running. If it | |||
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| as (1) | as (2) | |||||||
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| still will not reverse while running, replace | |||
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| the valve. | |
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| Hot | Cool | Hot, | Cool, | Hot | Hot | Defective pilot. | Replace valve. | |
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| Warm | Cool | Warm, | Cool, | Warm | *TVB | Defective compressor. | Replace compressor | |
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