Table of Contents
Advertisement
TEST PINS
STATUS LED
FIGURE 9: Demand Defrost Control
Heat Pump Safety Switch Operation
The unit is equipped with a safety package. The high pressure switch
prevents the pressure in the refrigeration system from becoming too
high. The loss of charge switch protects against loss of charge due to a
leak in the refrigeration system. If either of these safety switches open,
the unit will be shut off for the 5-min anti-short cycle time. Once this has
expired, a 6-h elapsed run timer begins. If a second opening of a safety
switch occurs during this 6-h period, the compressor will be locked out.
To reset the lockout function:
1. Remove power from the control's thermostat first-stage (Y) input for
longer than 2 s.
2. Remove power from R for more than 2 s.
3. Short the TEST pins together for more than 2 s while Y is ener-
gized.
4. Short the TEST pins together for more than 5 s while Y is de-ener-
gized.
Table 17: Test Pins
Test Pin Shorted
With Y Call
Greater than 2 s
Bypass ASCD
Greater than 5 s
Forced defrost
Table 18: Fault Codes
Description
High-pressure switch fault (not in lockout yet)
System in high-pressure switch lockout (last mode of
operation was normal compressor)
System in high-pressure switch lockout (last mode of
operation was defrost)
System in loss of charge switch lockout (last mode of
operation was normal compressor)
Low Voltage (<19.2 VAC) preventing further relay
outputs for > 2 s
Low Voltage (<16 VAC) stopped current relay outputs
for > 2 s
Liquid Line sensor failure (Open or Shorted)
Outdoor ambient sensor failure (Open or Shorted)
Control Failure
Johnson Controls Ducted Systems
Electric Heat Limit Switch Operation
6HK three-phase heat kits use a normally closed low voltage limit
switch, normally closed line voltage limit switch, and a normally closed
fusible link. If the fusible link opens, it must be replaced with the appro-
priate OEM part and the cause must be investigated and corrected.
When the limit switch opens, the heating elements will turn off. The
indoor blower will continue to run. The limit switch will automatically
reset when the temperature has fallen to a normal level, at which time
the heating elements will be turned on again.
Table 19: Thermostat Signals
Signal
Without Y Call
Display error codes
G and W
Clear error codes
STATUS LED
2 Flashes
G and Y
3 Flashes
4 Flashes
5 Flashes
6 Flashes
G, Y, and
7 Flashes
8 Flashes
9 Flashes
10 Flashes
* Motor program has 60-s blower off delay on all 5 speed taps.
State
Board Function
ON
Indoor blower instant on
G
OFF
Indoor blower off after 60-s delay
Indoor blower instant on
ON
Electric heat stages on (if so equipped)
W
Electric heat stages off (if so equipped)
OFF
Indoor blower off after 60-s delay
Indoor blower instant on in heating speed
ON
Electric heat stages on (if so equipped)
Electric heat stages off (if so equipped)
W OFF
Indoor blower switches to continuous fan speed
Outdoor fan instant on
Indoor blower instant on in cooling speed
ON
Compressor on (after any anti-short cycle delay)
System operates in heat pump heating mode
Compressor instant off
Y OFF
Outdoor fan instant off
Indoor blower switches to continuous fan speed
Outdoor fan instant on
Indoor blower instant on in cooling speed
ON
Compressor on (after any anti-short cycle delay)
Reversing valve energized
System operates in cooling mode
O
Compressor instant off
Outdoor fan instant off
Y and O
OFF
Reversing valve de-energized
Indoor blower switches to continuous fan speed
5151094-UIM-H-0220
DEFROST CURVE
SELECTION JUMPER
A0349-001
15
Advertisement
Table of Contents
