Genie GTH-844, Service And Repair Manual

Page: 73 / 187

April 2017 Service and Repair Manual
Manifolds
Part No. 1272854 GTH-844 61
7-6
Valve Coils
How to Test a Coil
A properly functioning coil provides an
electromotive force which operates the solenoid
valve. Critical to normal operation is continuity
within the coil that provides this force field.
Since coil resistance is sensitive to temperature,
resistance values outside specification can produce
erratic operation. When coil resistance decreases
below specification, amperage increases. As
resistance rises above specification, voltage
increases.
While valves may operate when coil resistance is
outside specification, maintaining coils within
specification will help ensure proper valve function
over a wide range of operating temperatures.
Electrocution/burn hazard.
Contact with electrically charged
circuits could result in death or
serious injury. Remove all rings,
watches and other jewelry.
1 Tag and disconnect the wiring from the coil to
be tested.
2 Test the coil resistance.
Result: The resistance should be within
specification, plus or minus 30%.
Result: If the resistance is not within
specification, plus or minus 30%, replace the
coil.
Valve Coil Resistance
Specification
Note: The following coil resistance specifications
are at an ambient temperature of 68°F / 20°C. As
valve coil resistance is sensitive to changes in air
temperature, the coil resistance will typically
increase or decrease by 4% for each 18°F / 10°C
that your air temperature increases or decreases
from 68°F / 20°C.
Valve Coil Resistance Specification
Description Specification
DO3 valve, 3 position 4 way
12V DC with diode
(schematic items SVD1)
5.6Ω
Solenoid valve, 2 position 2 way 12V
DC with diode
(schematic items SV9)
8.8Ω
Solenoid valve, 2 position 3 way 12V
DC with diode
(schematic items SV5, SV7, SV6)
8.8Ω
Solenoid valve, 2 position 4 way 12V DC
with diode
(schematic items SV1, SV2, SV3, SV4)
8.8Ω