12
YD
WD
GD
BD
RD
LOGIC
BOARD
160
OHMS
COOL
HEAT
SWITCHING
CENTER
(SYHPA)
GREEN
CALL LIGHT
OFF
K1
LOGIC
BOARD
TR
1TR2
POWER
K1
F
U
S
E
3P3T
SWITCH
K1
COOL
HEAT
OFF
OFF
E.M.
HEAT
ON
FAN
ON
AUTO
O
B
COOL
HEAT
OFF
O/B
Y
G
R
W2
E
L
C
E.M. HT LIGHT
(RED)
COMP. FAIL
(YELLOW)
SYSTEM 1000 SWITCHING CENTERS – GAS/ELECTRIC SYGE
SYSTEM 1000 SWITCHING CENTERS – HEAT PUMP SYHPA
WD
YD
GD
BD
RD
LOGIC
BOARD
K1
160
OHMS
K1
LOGIC
BOARD
TR1
TR2
POWER
COOL
HEAT
K1
COOL
HEAT
W
Y
R
G
SWITCHING CENTER
FAN
ON
AUTO
GREEN
CALL LIGHT
SIMPLIFIED SCHEMATIC, SYGE
SIMPLIFIED SCHEMATIC, SYHPA
WIRING
2
3
4
5
NOTES:
24V damper transformer. Requires in line fuse. See table on page
42 for sizing transformers and fuse.
Refer to page 41 for five wire link wire sizing.
C terminal for hard wired electronic thermostats only.
Open motor not utilized on low pressure (spring open) dampers.
If using more than one damper per thermostat, refer to Paralleling
Zone Dampers section, pages 23 and 44.
1
OVERVIEW
The SYHPA Switching Center is a manual changeover, single stage cool,
two stage heat, heat pump System Controller. It can control up to 7 zone
thermostats. Its function is to look for calls from the zone thermostats for
the mode (heat/cool) selected. If a call is received, it sends a signal to close
the dampers of all zones not calling and sends a signal to the heat pump
unit to energize heating or cooling.
The Switching Center is used in conjunction with a SYCAP Capacity
Controller. The SYCAP cycles the heat pump on and off to maintain the
leaving air temperature within a set range. Refer to the SYCAP in the
Capacity Controller section (pg. 33) for more information.
