FORM 145.20-IOM1 (908)
15
JOHNSON CONTROLS
LD13501
FIG. 4 -
FIELD WIRINg DIagRaM
17. SEQUENCE OF OPERATION ON
COOLING CYCLE – VPC & VPH UNITS
1. Room thermostat calls for cooling, connecting R
to y terminals.
2. The compressor and outdoor fan start immediately
on a call for cooling. air circulating fan also starts
immediately with cooling operation.
3. When the room thermostat is satisfied, terminal Y
on the thermostat is de-energized.
4. The compressor, outdoor fan and indoor fan stop
immediately when the thermostat is satisfied.
5. a compressor restart delay timer is activated at
the end of each cooling cycle. a minimum delay
time of 3 minutes is required to ensure that system
pressures have equalized before a compressor
restart.
18. SEQUENCE OF OPERATION ON HEATING
CYCLE – VPC UNITS ONLY
1. Room thermostat calls for heat, connecting R and
W terminals.
2. Electric Heat sequencer relay (1S) is energized.
3. On 2kW through 5kW models the electrical heater
is energized between 1-24 seconds after time
delay is energized. Heating fan is energized si-
multaneously with heating element operation.
4. On a unit with two heating elements (6kW, 8kW, or
10 kW), the 2nd element will be energized by clo-
sure of the 2S sequencer contacts approximately
90 seconds after the first stage is energized.
5. When the room thermostat is satisfied, terminals
R and W on the thermostat open, de-energizing
the 1S/2S sequencer relays.
6. The bank of heating elements will be disconnected
in descending order, the indoor fan will continue
to run until the elements are de-energized.
19. SEQUENCE OF OPERATION ON HEATING
CYCLE – VPH UNITS ONLY
1. Room thermostat calls for heat, connecting R and
W terminals.
2. Hydronic Heat Circulating Pump/valve relay is
energized (field supplied). Heating fan is energized
simultaneously with hot water flow interlock.
(Note: an electric/hot water heat thermostat, which
energizes the indoor fan during the heating cycle,
must be used.)
3. When the room thermostat is satisfied, terminals
R and W on the thermostat open, de-energizing
the hot water pump/valve interlock relay.
Summary of Contents for VPC
Page 10: ...JOHNSON CONTROLS 10 FORM 145 20 IOM1 908 LD13501 FIG 3 Wall Sleeve Assembly ...
Page 18: ...JOHNSON CONTROLS 18 FORM 145 20 IOM1 908 LD13504 ...
Page 19: ...FORM 145 20 IOM1 908 19 Johnson Controls LD13505 ...
Page 20: ...JOHNSON CONTROLS 20 FORM 145 20 IOM1 908 LD13506 ...
Page 21: ...FORM 145 20 IOM1 908 21 Johnson Controls NOTES ...
Page 22: ...JOHNSON CONTROLS 22 FORM 145 20 IOM1 908 NOTES ...
