General Service Guide - Daikin WRA Installation And Maintenance Data

All models employ an electromechanical control system for maximum reliability.
Symptom
1. Noisy Operation.
2. Compressor will
not start.
3. Compressor starts but
hums and trips out
on overload.
4. Compressor starts but
cuts out on low
pressure control.
5. Compressor starts
but cuts out on high
pressure control.
6. Compressor runs on
heating cycle,
but does not heat.
IM 1072-1
Possible Trouble
a. Chattering contactor noise.
a. Lock Out Relay Open.
b. Loose electrical connections.
c. Refrigerant charge lost, low pressure
cutout open.
d. No control voltage to the compressor
contactor.
e. Contactor pulled in, but compressor still
won't start.
a. Run capacitor could be bad.
b. Voltage may be low.
c. Seized bearings on compressor.
a. Low liquid flow (heating cycle).
b. Low refrigerant charge.
c. Restriction in liquid refrigerant line.
d. Low airflow (cooling cycle).
e. Low pressure cutout may have incorrect
pressure function.
a. Condenser coils limed or restricted.
b. Malfunctioning high pressure control.
c. Reduced or lack of liquid flow.
d. Reduced evaporator air flow
(heating cycle).
a. Reversing valve may be defective.
b. Thermostat may be defective.
Water to Water Source Heat Pumps

General Service Guide

Method of Finding
a. Check contactor points, check for adequate control
voltage from transformer, and check control circuit
for shorts or breaks, check thermostat.
a. Turn thermostat off, then on.
b. Check all connections at contactor and compressor
terminal box for loose or burned connection on terminal.
c. Check for R-410A pressure.
d. Check for 24 volts across contactor coil.
If no voltage, check for thermostat circuit trouble
or for compressor safety controls open.
e. Check compressor overload circuit, contactor points, etc.
a. Check capacitor.
b. Check it.
c. Replace compressor.
a. Check liquid flow.
b. Remove refrigerant, repair leak and recharge.
c. Check pressures and look for frosting across
the restriction.
d. Check and correct.
e. Check low pressure cutout for correct pressure.
a. Check it. (Open systems)
b. Check that the control is cutting out at the correct
pressure.
c. Check liquid.
d. Check air flow.
a. See that it has shifted.
b. Check wiring diagram.
Page 41 of 44