Operating instructions

18
PROBLEMS POSSIBLE CAUSE CHECKS AND CORRECTIONS
Thermostat Check setting, calibration, and wiring, if thermostat has an anticipator, set it at 1.0
or 1.2.
Wiring Check for loose or broken wires at compressor, capacitor, or contactor.
Blown Fuse Replace fuse or reset circuit breaker. (Check for correct size fuse or circuit
breaker.)
High or Low Pressure Controls The unit could be off on the high or low-pressure cutout control. Check water
GPM, ambient temperature and loss of refrigerant. If the unit still fails to run,
check for faulty pressure controls individually. Replace if defective.
Defective Capacitor Check capacitor, if defective remove, replace, and rewire correctly.
Voltage Supply Low If voltage is below minimum voltage specified on the data plate, contact local
power company. Check voltage at compressor for possible open terminal.
Low Voltage Circuit Check 24-volt transformer for burn out or voltage less that 18 volts. With a
voltmeter, check signal from thermostat at Y to X, M1 on controller to X,
capacitor voltage drop. Replace component that does not energize.
Compressor Overload Open In all cases an "internal" compressor overload is used. If the compressor motor is
too hot, the overload will not reset until the compressor cools down. If the
compressor is cool and the overload does not reset, there may be a defective or
open overload. Replace the compressor.
Compressor Motor Grounded Internal winding grounded to the compressor shell. Replace the compressor. If
compressor burnout replace the liquid line filter/drier.
Compressor Windings Open Check continuity of the compressor windings with an ohmmeter. If the windings
are open, replace the compressor.
Hydronic pump runs
but compressor does
not, or compressor
short cycles.
Seized Compressor Try an auxiliary capacitor in parallel with the run capacitor momentarily. If the
compressor still does not start, replace it.
Thermostat Improperly located thermostat (e.g. near kitchen, sensing inaccurately the comfort
level in living areas). Check anticipator setting. Should be 1.0 or 1.2.
Unit short cycles Compressor Overload Defective compressor overload, check and replace if necessary. If the compressor
runs too hot, it may be due to a insufficient refrigerant charge.
Aquastat The differential is set to close on aquastat. Increase differential setting to 15
o
F.
Wiring and Controls Loose wiring connections, or control contactor defective.
Thermostat Improperly Set Is it below room temperature? Check the thermostat setting.
Unit will not Defective Thermostat Check thermostat operation. Replace if found defective.
operate in Incorrect Wiring Check for broken, loose, or incorrect wires.
"heating" Aquastat set Too High Heat pump is trying to heat hot water to too hot of a temperature (over 120
o
F).
Reduce aquastat setpoint.
Reversing Valve does not Shift Defective solenoid valve will not energize. Replace solenoid coil.
Reversing Valve does not Shift,
the Valve is Stuck
The solenoid valve is de-energized due to miswiring at the unit or thermostat-
correct wiring. Replace if valve is tight or frozen and will not move. Switch from
heating to cooling a few times to loosen valve.
Aquastat set Too Low Heat pump is trying to cool water too low. Increase aquastat setpoint.
Unit does not cool
(Heats Only)
Insufficient Antifreeze Water is freezing in hydronic coil. Check antifreeze level and add antifreeze to
obtain correct freeze protection.
Compressor Make sure the compressor is not in direct contact with the base or sides of the
cabinet. Cold surroundings can cause liquid slugging, increase ambient
temperature.
Contactor A "clattering" or "humming" noise in the contactor could be due to control voltage
less than 18 volts. Check for low supply voltage, low transformer output or extra
long runs of thermostat wires. If the contactor contacts are pitted or corroded or
coil is defective, repair or replace.
Rattles and Vibrations Check for loose screws, panels, or internal components. Tighten and secure.
Copper piping could be hitting the metal surfaces. Carefully readjust by bending
slightly.
Water and Airborne Noises Undersized ductwork will cause high airflow velocities and noisy operation.
Excessive water through the water-cooled heat exchanger will cause a squealing
sound. Check the water flow ensuring adequate flow for good operation but
eliminating the noise.
Noisy Operation
Cavitating Pumps Purge air from closed loop system.