Hitachi UTOPIA RAS-4HVRP2E - Page 155

7 Commissioning
Refrigerant cycle checklist
SMGB0136 rev.0 - 07/2021
153
7
b. Heating operation (this is applicable when the outdoor temperature is higher than 0 °C).
No. Check item Standard Causes Result
1
Is TdSH “15 - 55 ºC”?
TdSH = Td - Saturated vapor refrigerant
temperature
15 - 55 ºC
• Low: excessive refrigerant.
• High:insufcientrefrigerant.
• OUExpansionValve;Lockedand
Slightly Open or Closed.
2
Is Pd between “1.5” and “3.3”?
1.5 - 3.3
• Low:solenoidvalveSVAleak.
• High: excessive pressure loss in the
gas pipe.
3 Is Ps between "0.15" and "1.3"? 0.15 - 1.3
• Low: outdoor unit short-circuit.
• low/high:outdoorunitfanmotorfailure,
fan module failure or outdoor unit
ambient temperature thermistor failure.
4
Is the difference in temperature between
indoor units* more than 10 °C when iE
(indoor unit expansion valve) is "100?
* The difference in temperature between
indoor units means the following:
b3 (discharge air temperature) -b2 (air inlet
temperature) indicated on the remote control
by the check mode. However, this is only
applicable when b2 (Air inlet temperature) -b1
(setting temperature) is higher than 3 °C.
10 ºC and over
• Failure such as PCB, wiring, indoor
unit expansion valve and coil.
• Excessive pressure loss in the pipe.
• Thermistor failure for air discharge.
? NOTE
• The symbol with an underline _____ indicates checking item and the mark “ ” indicates checking data.
• For 3 HP models: Service Tools can be connected to TB1 in terminals 1 and 2.
• For 4-6 HP models: Service Tools can be connected to TB No.1 and TB No.2.