Specifications

10
MOTOR WINDING THERMAL PROTECTOR OR
HIGH-PRESSURE SWITCH – Turn START-STOP
Switch to "Stop", then to "Start". Entire unit stops; restart is
under timer control.
LOW-PRESSURE SWITCH-Automatic restart when
pressure rises to cut-in point.
OIL PRESSURE SAFETY SWITCH-Manually depresses
reset button devices and turn START-STOP switch to "Stop"
and then to "Start".
If any safety device action repeats. Do not make a second
attempt to restart unit until the cause is determined and
corrected.
Timer Controlled Restart- when power is restored after an
interruption; restart is automatic thru normal timer-controlled
cycle. When control circuit is reenergized, approximately 5
minutes will elapse before first compressor is energized.
When START-STOP switch is turned to "Stop" or when
low water temperature cutout opens during unit operation,
timer will start, run for approximately 5 minutes and stop.
Timer is now set for first compressor to start immediately
when operation is resumed.
Servicing 30HR Units-If it is necessary to open both main
power circuit breakers, first turn the control circuit START-
STOP switch to "Stop".
This de-energizes (and closes) the liquid line valves and
energizes the crankcase heaters while the compressors are off.
If only one main power circuit breaker will be open, first turn
the control circuit START-STOP switch to "Stop" and then
disconnect the control relay holding Coil in the control circuit
for the compressor that will be off This will de-energize the
liquid line valve for that circuit and energize the crankcase
heater for the off compressor. Then turn the control circuit
START-STOP switch to "Start” to restart the operable
compressor.
On 30HS units, the oil pressure safety switch(es) for the
off compressor(s) will open, causing the liquid line valve(s) to
close. The control circuit will remain energized and the
crankcase heater(s) for the off compressor(s) will energize. At
restart, depress the reset button on the oil safety switch, and
turn the START-STOP switch to "stop” then to "Start
TROUBLESHOOTING
SYMPTOMS PROBABLE CAUSE REMEDY
Power line open Reset circuit breaker
Check control circuit
for ground or short
Control circuit breaker
tripped
Reset breaker
Safety thermostat
tripped
Reset thermostat
Tripped power breaker Check the controls.
Find cause of trip and
reset breaker
Power off-restart
Pump binding-free
pump
Incorrect wiring
rewire
Condenser circulating
pump not running
Pump motor burned
Out-replace
Loose terminal
connection
Check connections
Improperly wired
controls
Check wiring and
rewire
Low line voltage Check line voltage-
determine location of
voltage drop and
remedy deficiency
Compressor motor
defective
Check motor winding
for open or short rep-
lace compressor, if
necessary
Compressor
does not run
Seized compressor Replace compressor
Raise differential
setting
Check capillary for
pinches
Low-pressure control
erratic in action
Replace control
Compressor suction
Valve leaking
Replace valve plate
Compressor suction
Shut off valve partially
closed
Open valve
Compressor
cycles on low
pressure control
Low refrigerant charge Add refrigerant
SYMPTOMS PROBABLE CAUSE REMEDY
Compressor
Cycles on low-
Pressure control
Plugged compressor
Suction strainer
Clean strainer or
Replace
Check capillary tube
for pinches
High-pressure control
Erratic in action
Set control as
required
Compressor discharge
valve partially closed
Open valve, or
replace
if defective
Air in system Purge
Condenser scaled Clean condenser
Compressor
Cycles on high
Pressure control
Condenser water pump or
fans not operating
Start pump repair or
replace if defective
Low refrigerant charge Add refrigerant
Control contacts fused Replace control
Air in system Purge
Partially plugged or
plugged expansion valve
or strainer
Clean or replace
Defective insulation Replace or repair
Service load too high Keep doors and
windows closed
Unit operates long
or continuously
Inefficient compressor Check valves,
replace
If necessary
Support piping as
required
Piping vibration
Check for loose pipe
connectors
Add refrigerant Expansion valve hissing
Check for plugged
liquid line strainer
Check valve plates
for valve noise
Replace compressor
(worn bearings)
System noises
Compressor noisy
Check for loose
compressor hold
down bolts