Auxiliary (Electric) Heat Control; Defrost - Carrier WeatherMaster 50HCQ04-12 Service And Maintenance Instructions

INPUTS
OUTPUTS
CONFIGURATION
SPEED-UP
CONFIGURATION
NOTES:
1. Jumper for 1-3 seconds: Factory Test, defrost runs for 9 seconds.

Auxiliary (Electric) Heat Control

The 50HCQ unit can be equipped with one or two auxiliary
electric heaters, to provide a second stage of heating. The DFB
will energize this Heating System for a Stage 2 Heating Com-
mand (heaters operate concurrently with compressor(s) in the
Stage 1 Heating cycle), for an Emergency Heating sequence
(compressors are off and only the electric heaters are ener-
gized) and also during the Defrost cycle (to eliminate a "cold
blow" condition in the space).

Defrost

The defrost control mode is a time/temperature sequence.
There are two time components: The continuous run period
and the test/defrost cycle period. The temperature component
is provided by Defrost Thermostat 1 and 2 (DFT1 and DFT2
(D08-D09 only) mounted on the outdoor coil.
The continuous run period is a fixed time period between the end
of the last defrost cycle (or start of the current Heating cycle)
during which no defrost will be permitted. This period can be set
at 30, 60, 90 or 120 minutes by changing the positions of DIP
switches SW1 and SW2 (see Fig. 34 and Table 9). The default
run periods are 60 minutes for unit sizes 04-06, 30 minutes for
Fig. 35 — Defrost Control Board Location
Table 8 — 50HCQ Defrost Board I/O and Jumper Configurations
POINT NAME TYPE OF I/O
G Fan DI, 24Vac
Y1 Cool 1 DI, 24Vac
Y2 Cool 2 DI, 24Vac
W1 Heat 1 DI, 24Vac
W2 Heat 2 DI, 24Vac
R Power 24Vac
C Common 24Vac
DFT1 DI, 24Vac
DFT2 DI, 24Vac
IFO Fan On DO, 24Vac
OF OD Fan On DO, 24Vac
RVS1 DO, 24Vac
RVS2 DO, 24Vac
COMP 1 DO, 24Vac
COMP 2 DO, 24Vac
HEAT 2 DO, 24Vac
COM 24Vac
Select Jumper 24Vac
2 Compressor 24Vac
Speed-Up Jumper
Speed-Up Jumper
CONNECTION PIN NUMBER
P2-3
P2-5
P2-4
P2-7
P2-6
P3-1
P3-2
DFT-1 to DFT-1
DFT-2 to DFT-2
P3-9
OF
P3-7 to P3-5
P3-6 to P3-4
P3-10
P3-8
E-HEAT
P3-3
P1-1
P1-3
JMP17
JMP18
2. Jumper for 5-20 seconds: Forced Defrost, defrost runs for 30 sec-
onds if DFT2 is open.
unit size 07, 90 minutes for unit sizes 08-09 and 60 minutes for
unit size 12.
Fig. 36 — DIP Switch Settings — Defrost Board
22
UNIT
NOTE
CONNECTION
LCTB-G
LCTB-Y1
LCTB-Y2
LCTB-W1
LCTB-W2
CONTL BRD-8
CONTL BRD-4
REHEAT-2
OFR
Energize in COOL
Energize in COOL
FPT-REHEAT-6
REHEAT-8
HC-1 (TB4-1)
HC-1 (TB4-3)
Use for 50HCQD