SMC Networks HRS012-A-10 Series Service Manual page 30

HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
Check the circulating fluid temperature sensor (PT1) after it is replaced.
6.
Replace the circulating fluid temperature sensor (PT1). (See section "4.5.1 Replacement of
temperature sensor (PT1)".) After replacing, check that all the check items shown in "5. Check the
circulating fluid temperature sensor (PT1)" are correctly followed.
7. Flow rate of the circulating fluid is less than 5 L/min.
Install a flow meter, and check the flow rate of the circulating fluid.
Check the pump performance.
8.
Install a flow meter. Refer to the "Pump capacity" graph" shown in the catalogue and check that the
pump capacity is suitable for the circulating fluid outlet pressure and the circulating fluid flow rate.
Circulating fluid is contaminated.
9.
Contamination contained in the circulating fluid adheres to the heat exchanger (evaporator), and it
decreases the heat exchanger performance.
Open the cap of the tank, and check visually the contamination (e.g. deformation, foreign matter,
abnormal smell) of the circulating fluid inside the tank.
When the visual check finds contamination in the circulating fluid, check the influence of the
contamination to the heat exchanger by following the instructions shown below.
(1) Connect the circulating fluid outlet directly to the fluid return port with a valve mounted to the
outlet port with a shorter piping to make it possible to operate the system at flow rate of
circulating fluid at 7 L/min.
(For Option T, adjust the flow rate so that the circulating fluid discharge pressure will be
approximately 0.4 MPa.)
(2) Set the circulating fluid temperature to 20 oC, and operate the Thermo-Chiller.
(3) Check the temperature shown for "t2: Circulating fluid return temperature" and "t3: Compressor
inlet temperature" in the "Check Monitor Menu".
(4) Displayed temperature will be as shown below in accordance with level of contamination of the
heat exchanger.
<With no contamination with the heat exchanger>
"t3: Suction temperature of the compressor" ≥ "t2: Circulating fluid return temperature" -5
<With contamination with the heat exchanger>
"t3: Suction temperature of the compressor" ˂ "t2: Circulating fluid return temperature" -5
e.g. (Normal) t2: 21.5, t3: 23.8, (Abnormal) t2: 21.5, t3: 15.5
10. Check the pressure sensor in the refrigerant circuit.
Two pressure sensors, one for high pressure and one for low pressure, are used for the refrigerant
circuit. Take the following instructions to check for any abnormality with the pressure sensors:
(1) Stop the Thermo-Chiller operation.
(2) Check the temperature shown for "Ph: Refrigerant circuit pressure on the high pressure side"
and "PL: Refrigerant circuit pressure on the low pressure side" in the "Check Monitor Menu".
(3) If the pressure value shown by each sensor is +/- 0.1 MPa (Ph = PL +/- 0.1), it means that the
pressure sensors are operating correctly.
3.3 Troubleshooting
3-14
o
C
o
C
HRS Series