PowerAir Pressure Switch Test and Repair
During the Compression Cycle
When the storage tank is filled to the preset pressure the pressure switch will open and stop the compressor.
During the Purge Cycle
The pressure switch shuts off current to the compressor head(s) and the solenoid / purge valve. A mechanical valve on the pressure switch opens up to unload the compressor headlines. At the same time the solenoid opens, starting the purge cycle.
Cut-In / Cut-Out time
Cut-In / Cut-Out is the minimum and maximum discharge pressures at which the compressor will switch from unload to load operation (cut-in) or from load to unload (cut-out). The pressure switch controls Cut-In / Cut-Out times.
Pressure Switch Testing
Serial Number Range: 0703P210001
thru 0903P210361, 0703P220001
thru 0903P221139, 0703P210001
thru 0903P321137, 0703P210001
thru 0902P520467, 0703P210001
thru 0903P720190
|
Model |
P21 | P22 | P32 | P52 | P72 |
| Serial Number | 0703P210001 thru 0903P210361 | 0703P220001 thru 0903P221139 | 0703P210001 thru 0903P321137 | 0703P210001 thru 0902P520467 | 0703P210001 thru 0903P720190 |
When testing components with power on, use care to prevent electrical shock.
Test pressure switch during compression cycle, when pressure switch is closed.
1.Perform Adjustment. Refer to:Pressure Switch Adjustment
2.Turn Power off.
3.Remove pressure switch cover and verify there are no black/burnt melted wires. If there are, replace pressure switch. Refer to:Pressure Switch Cover
4.Turn Power On, Bleed tank pressure down to less than 80 PSI. Pressure switch will make an audible click.
5.Set meter to VAC.
6.Place black meter probe on common ground. Use red meter lead to test for voltage at both yellow wire connections.
|
Meter Reading |
Status |
Required Action |
|---|---|---|
|
24 VAC at only one yellow wire terminal. |
|
Replace Pressure Switch. |
|
24 VAC at both yellow wire terminals. |
|
Pressure Switch OK. |
Serial Number Range: 0904P210365
thru Present, 0904P221146
thru Present, 0904P321145
thru Present, 0904P520474
thru Present, 0903P720191
thru Present
|
Model |
P21 | P22 | P32 | P52 | P72 |
| Serial Number | 0904P210365 thru Present | 0904P221146 thru Present | 0904P321145 thru Present | 0904P520474 thru Present | 0903P720191 thru Present |
High Voltage. When testing components with power on, use care to prevent electrical shock.
1.Perform Adjustment. Refer to:Pressure Switch Adjustment
2.Turn Power off.
3.Remove pressure switch cover and verify there are no black/burnt melted wires. If there are, replace pressure switch. Refer to:Pressure Switch Cover
4.Turn Power On.
5.Set meter to VAC.
6.Bleed tank pressure down to less than 80 PSI. Pressure switch will make an audible click.
a.Check line voltage across L1 and L2.
b.Check line voltage across T1 and T2.
c.These voltages should be the same.
|
Meter Reading |
Status |
Required Action |
|---|---|---|
|
T1 / T2 = No Line Voltage |
|
Replace Pressure Switch. |
|
T1 / T2 = Line Voltage |
|
Pressure Switch OK. |
