Troubleshooting; Thermistor; Control Sensors - Carrier AQUAZONE 50HQP072-120 Installation And Service Instructions Manual

TROUBLESHOOTING

When troubleshooting problems with a WSHP, see
Table 18.
A thermistor may be required for single-
Thermistor —
phase units where starting the unit is a problem due to low
voltage. See Fig. 26 for thermistor nominal resistance.
The control system employs 2 nom-
Control Sensors —
inal 10,000 ohm thermistors (FP1 and FP2) that are used for
freeze protection. Be sure FP1 is located in the discharge fluid
and FP2 is located in the air discharge. See Fig. 27.
AI R
COI L
AIRFLOW
( °C)
THERMIST OR
CONDENSA TE
OVERFLO W
(CO)
LEGEND
COAX — Coaxial Heat Exchanger
Airflow
Refrigerant Liquid Line Flow
AIRFLO W
( °C)
EXP ANSION
VA LV E
FP 2
FP 1
LIQUI D
LIN E
AIR COI L
WA TE R
FREEZ E
COI L
PROTECTIO N
PROTECTIO N
Fig. 27 — FP1 and FP2 Thermistor Location
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
-17.7
Fig. 26 — Thermistor Nominal Resistance
COAX
WA TER IN
WA TER OUT
30
-6.6 4.4 15.6 26.7 37.8
Temperature (C)
SUCTIO N
COMPRESSOR
DISCHARGE
a50-8163
48.9 60.0