Checkout Procedure For The Female Step Load Outputs; Checkout Procedure For The Step Load Solenoids Valve And Piston; Checkout Procedure For The Male Load-Unload Outputs - Trane RTHD Troubleshooting Manual

Checkout Procedure for the Female Step Load Outputs

WARNING
Live Electrical
Components!

Checkout Procedure for the Step Load Solenoids Valve and Piston

Checkout Procedure for the Male Load-Unload Outputs

RLC-SVD05A-EN
Compressor Capacity - RTAC
A dual triac LLID (1U17, 2U17,) controls the female solenoid valve on the
compressor with a 115VAC relay output. Refer to the wiring diagrams in the
control panel for the following procedure.
During installation, testing, servicing and troubleshooting of this product, it may
be necessary to work with live electrical components. Have a qualified licensed
electrician or other individual who has been properly trained in handling live
electrical components perform these tasks. Failure to follow all electrical safety
precautions when exposed to live electrical components could result in death or
serious injury.
With a particular compressor running, the relay may be checked (under load) by
measuring the voltage for terminal J2-1 or J3-1 to neutral. The relay operators in
the high side and switches power to J2-1 and/or J3-1, to move the female step
load valve to the loaded position. When CH530 decides to load the compressor,
the female step load is energized continuously. To assure that loading is
occurring, it may be necessary to make slight adjustments to the chilled water
setpoint to force the action.
1 Connect a manifold gauge set to the schrader valve located at the side of the
piston housing. Refer to
side of the step load piston and, therefore, will allow direct measurement of
the pressure that actuates the step load valve.
2 Observe the pressure during a compressor start. Initially, the pressure should
drop to suction pressure. The compressor will run unloaded for at least 45
seconds.
3 When the CH530 begins to load the compressor the solenoid will actuate and
supply discharge pressure to the piston.
4 If after verifying the 115 VAC has been applied to the step load solenoid, the
pressure does not increase to discharge pressure, the step load solenoid coil
and/or the valve must be replaced.
The percent RLA of the compressor should increase. If the percent RLA does
not increase, the step load valve is stuck and compressor should be replaced.
Note: All limits and safeties are still active. If the chiller enters into a condenser,
current, or evaporator limit. Continuously monitor the operating mode.
A dual triac LLID (1U16, 1U21,2U16, 2U21) controls the load and unload solenoid
valve on the compressor with a 115VAC triacs (solid state relays). Unlike
mechanical relays however, a triac has a rather high leakage current when off,
comparatively speaking. While the leakage is not nearly enough to actuate a
solenoid valve, it may under a no load condition (as would be experienced when
a solenoid coil fails open), look like it was stuck "on" when using a voltmeter to
Figure 33. This schrader allows access to the back
49