Reznor PDH Operation Manual PreevA - Manual (Page 27)

Form O-PreevA, P/N 234661R8, Page 27
temporary suction line filter drier. If the pressure drop exceeds 8 psig, recover
the refrigerant, replace the suction line filter drier with the same type as
removed, replace the liquid line filter drier, evacuate the circuit, and re-charge
with the recovered refrigerant).
Continue to monitor the pressure drop through the suction line filter drier and
repeat the process above until the pressure does not exceed 8 psig after
several hours of operation. (NOTE: System must be allowed to run no more
than 72 hours with a suction line filter drier.)
b) Allow the system to operate for 4-8 hours. Recover the refrigerant and take an
oil sample. Retest the oil for acid.
c) If the test for acid is negative, remove the suction line filter drier, replace the
liquid line drier, evacuate, and re-charge the system with the recovered refriger-
ant.
If the test indicates acid, replace both the liquid line filter drier and the suction
line filter drier and repeat b) and c).
CAUTION: After cleanup is complete, remove the suction
line filter drier. See Hazard Levels, page 2.
d) Verify subcooling and superheat (refer to Step 11).
e) When the system is operating properly, remove the gauges.
IF the oil measured in Step 2 was not significantly less than that shown
in the table on page 21 or the acid test in Step 2 did not indicate a
compressor burnout, continue to the review in Step 13.
□
Step 13 . Review ALL Steps to ensure that nothing was
overlooked.
3.7.5 Modulating
Reheat Control
(Option AUR1)
Function: Units with modulating reheat control (Option AUR1) have a temperature
control board with a potentiometer, an air temperature sensor, and an electric dis-
charge bypass valve. When reheat is active, the sensor monitors the air temperature
as it leaves the reheat coil. Based on the potentiometer setpoint, the board will open
or close the bypass valve. If the leaving air temperature is higher than the setpoint, the
board will open the valve adding refrigerant hot gas to the refrigerant liquid before it
enters the pre-cool coil. This reduces the coil's ability to absorb the heat, and thus, the
reheat coil's ability to reject. If the leaving air temperature is lower than the setpoint,
the opposite occurs.
Service: Check the wiring connections at the board. The board is polarity sensitive;
positive connects to terminal 1 and negative to terminal 2.
The valve may be tested by measuring the resistance of the leads. Remove the power
and the leads from the board before testing. Resistance between the black and white
leads should be about 75 Ohms. Resistance between the green and red leads should
be within 5% of the white and black.
Use only factory-authorized replacement parts.
3.8 Optional
Evaporative
Cooling Module
Media
Media
Media
Media
Airflow
Door Panel
When equipped with an
evaporative cooling module,
the evaporative cooling
module is always the first
module in system. Air enters
the system through the
evaporative cooling media.
See the heater installation
manual for additional
information about the
operation of the evaporative
cooling module.