MODELS WHR-070A THRU 120A (Continued)
O F F C Y C L E
(Refer to Diagrams 5 & 6)
On a decrease in entering water temperature thermo-
stat (TC1), stage #2 will be satisfied and the con-
tacts will open.
1. LT7 cooling light will turn off.
2. R5 relay will be de-energized, contacts R5 will
open and de-energize contactors M5 & M7.
3. Compressor 1B will turn off immediately.
A further decrease in entering water temperature
wi II open thermostat contacts #1.
1. R1 relay will be de-energized, opening contacts R1
which allows the liquid line solenoid to close.
2. Refrigerant flow to the evaporator will be shut off
and the unit will begin to pump down.
3. The compressor will continue to operate thru pump-
down relay R3 since R1 is open.
4. The suction pressure will drop until low pressure
switch LP1 opens. Contactors Ml & M3 and relay
R3 will open and compressor 1A will turn off and
stay off until relay R1 is again energized thru the
thermostat.
In the event compressor 1A is off on oil pressure
safety (OP1) or motor overload protection MP1, then
compressor 1B will serve as the pumpdown compress-
or.
1.
2.
3.
4 .
Again thermostat #2 will open and de-energize re-
lay R5 and open contacts R5.
The compressor 1B will continue to operate thru
pumpdown relay R7. R7 will be in the circuit in
this case since the auxiliary contact on
Ml
con-
tactor is closed.
#1 thermostat will open on further decrease in
water temperature, closing the liquid line solenoid
(LLS1) thru R1 relay.
C o m p r e s s o r 1B will continue to run until the cir-
cuit is opened by low pressure control LP1.
FIGURE 18 COMPRESSOR LOCATION
(REFERENCE TO ELECTRICAL DIAGRAMS 1 & 2)
COMP. 1A
COMP. 1B
COMP. 20
-
COMP. 2A
-
I
CONTROL
PANEL NO. 1
CONTROL
PANEL NO. 2 1
TOP VIEW OF UNIT
T A B L E 7 COMPRESSOR HORSE POWER
Page 13
