Product data

79
Typical wiring schematic — 50TFQ004-007
LEGEND
AHA — Adjustable Heat Anticipator
AWG — American Wire Gage
C—Contactor, Compressor
CAP — Capacitor
CB — Circuit Breaker
CC — Cooling Capacitor
CH — Crankcase Heater
COMP — Compressor Motor
D—Diode
DB — Defrost Board
DFT — Defrost Thermostat
EC — Enthalpy Control
ECON — Economizer
EPS — Emergency Power Supply
(Nine-Volt Battery)
ER — Economizer Relay
FSS — Filter Status Switch
FPT — Freeze-Up Protection Thermostat
FU — Fuse
GND — Ground
HC — Heater Contactor (Strip Heat)
HPS — High-Pressure Switch
HR — Heater Relay
IFC — Indoor-Fan Contactor
IFM — Indoor-Fan Motor
LPS — Low-Pressure Switch
LSM — Limit Switch (Manual Reset)
MTR — Motor
OAT — Outdoor-Air Thermostat
OFM — Outdoor-Fan Motor
P—Plug
PL — Plug Assembly
QT — Quadruple Terminal
R—Relay
RVS — Reversing Valve Solenoid
SAT — Supply-Air
Thermostat
ST — Start Thermistor
SW1 — Switch Fully Open
SW2 — Switch Fully Closed
SW3 — Switch Min.
Vent Position
SW4 — Switch Max.
Vent Position
TB — Terminal Block
TC — Thermostat-
Cooling
TH — Thermostat-
Heating
TRAN — Transformer
Field Splice
Marked Wire
Terminal (Marked)
Terminal (Unmarked)
Te r m i n al B l o ck
Splice
Splice (Marked)
Factory Wiring
Field Control Wiring
Field Power Wiring
Accessory or
Optional Wiring
To indicate common
potential only. Not to
represent wiring.
NOTES:
1. If any of the original wire furnished
must be replaced, it must be
replaced with Type 90 C wire or its
equivalent.
2. Thermostat: HH07AT170, 172, 174
& P272-2783.
Subbase: HH93AZ176, 178 &
P272-1882, 1883.
3. Set heat anticipator at .8 amp for
first stage and .3 amp for second
stage.
4. Use copper conductors only.
5. Use copper, copper-clad aluminum
or aluminum conductors.
VOLTAGE
RATING
CB
MUST
TRIP
AMPS
MFG. PT. NO.
24V
POTTER &
BRUMFIELD
W28X-1024-3.2 3.2
6.
50TFQ004-01250TFQ004-012