JOHNSON CONTROLS
14
FORM 145.26-IOM1 (908)
17. SEQUENCE OF OPERATION ON
HEATINg CYCLE
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.
An electric heat / hot water heat thermo-
stat, which energizes the indoor fan dur-
ing 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.
SEQUENCE OF OPERATION ON COOLINg CYCLE
1 . Room thermostat calls for cooling connecting R
to y terminals.
2 . The compressor and condenser fan start immedi-
ately 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 module is de-energized.
4 . The compressor and condenser fan stop immedi-
ately when the thermostat is satisfied.
5 . The air circulating fan continues to run for an off
delay period of 100 seconds. The off delay on the
cooling cycle is factory set for maximum efficiency.
adjustment of this delay is not recommended.
18. START-UP CHECKLIST
Before starting furnace for the first time, be sure you can
answer “yes” to each of these questions:
1 . Is the unit level?
2 . Have you cleared away all loose construction and
insulation materials?
3 . Is unit installed within proper clearances to com-
bustible materials? See Section 6.
4 . Does electrical wiring follow current National
Electrical Code aNSI 70 or CSa C22.1 as well as
local codes? See Section 15.
5 . Is furnace electrically grounded? See Section
16.
6 . Is room thermostat properly installed? See Sec-
tion 16.
7 . Is duct work system correctly sized and sealed?
See Section 11.
8 . Are air filters in place and correctly sized? See
Section 12.
19. SYSTEM BALANCE
Blower speed taps are factory set for optimum heating
and cooling airflow ranges. Refer to Table 3 for factory
blower speed settings, and minimum allowable cooling
airflow.
If required, the Heating speed tap may be increased,
or reduced from the initial factory setting. The airflow
rate through the hot water coil is the principal factor in
determining total heating output. Reducing the blower
speed will result in decreased heating output, but higher
discharge air temperature. Increasing blower speed will
produce maximum heat output, with lower discharge
temperatures.
At maximum heating airflow, some duct
system configurations and supply regis
-
ter locations may result in “cold blow”.
Installed system must be test run to ensure operation
with sufficient heating and cooling airflow. Total system
static pressure should be measured and compared with
airflow performance data shown in Table 1.
