HRX-MM-N007
Chapter 3 Alarm Indication and Troubleshooting
HRS Series
3.3 Troubleshooting
3-23
6.
Check the circulating fluid temperature sensor (PT1).
Two circulating fluid temperature sensors are used; one is for the outlet port (PT1) and one for the
return port (PT2). Compare the temperatures sensed by the temperature sensors under the
conditions shown below to judge if the values provided by the temperature sensors are correct or
not:
(1) Connect a shorter pipe directly from the circulating fluid outlet port to the return port of the
Thermo-Chiller with a valve mounted to the outlet port. (Mount a valve to the outlet port to make
it possible to adjust the flow rate roughly.)
(2) Operate the Thermo-Chiller and stabilize the temperature.
(3) Check the temperature shown for "t1: Circulating fluid outlet temperature" and "t2: Circulating
fluid return temperature" in the "Check Monitor Menu".
If the temperature is within the range of t1 = t2 +/- 2
o
C, operation of the circulating fluid
temperature sensor (PT1) is normal.
7.
Check the circulating fluid temperature sensor (PT1) after it is replaced.
Replace the circulating fluid temperature sensor (PT1). (See section "4.5.1 Replacement of the
temperature sensor (PT1)".) After replacing, check that all the check items shown in "6. Check the
circulating fluid temperature sensor (PT1)" are correctly followed.
8.
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.
9.
Check the pump performance.
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.
10.
Circulating fluid is contaminated.
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 checks find contamination in the circulating fluid, check the influence of the
contamination to the heat exchanger 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
o
C, 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
o
C
