035-16408-001 Rev. B (101)
10
Unitary Products Group
INDOOR BLOWER SPEED SETTINGS
Refer to the Tabular Data Sheet for the recommended air flow
settings for each size condensing unit.
Variable Speed Air Handlers and Furnaces
- Set the high
speed cooling speed per the instructions for the air handler or
furnace by selecting the correct “cool” and “ADJ” taps. The
low speed setting will automatically be programmed for the
correct airflow. Verify the airflow by LED display on the speed
selection board.
Single Speed Air Handlers and Furnaces -
It is mandatory
a fan relay kit be applied to the furnace or air handler. The air
handlers are designed to use the 2SF06700124 fan relay and
the furnaces should use a SPDT 24VAC Coil (15 AMP rating
@ 115V). See figures 5 and 6 for wiring connections. The
ideal fan setting is to set the high speed (second stage) air
flow at the fan motor high speed and the low speed (first
stage) airflow at the fan low speed. If the low speed air flow is
too high, unsatisfactory dehumidifaction may occur on first
stage operation. To correct for unsatisfactory dehumidifica-
tion, either add a dehumidistat per figures 5 and 6 or change
the blower motor for better air flow performance.
Two Stage Furnaces
- The ideal fan setting is to set the high
speed (second stage) air flow at the fan motor high speed
and the low speed (first stage) airflow at the fan low speed. If
the low speed air flow is too high, unsatisfactory dehumidifac-
tion may occur on first stage operation. To correct for unsatis-
factory dehumidification, either add a dehumidistat per figure
7 or change the blower motor for better air flow performance.
SYSTEM START-UP
ENERGIZE CRANKCASE HEATER
This unit is equipped with a crankcase heater for the com-
pressor.
IMPORTANT -
An attempt to start the compressor without
at least 8 hours of crankcase heat will damage the compres-
sor.
In order to energize the crankcase heater, set the indoor ther-
mostat system switch to “OFF”. Close (turn on) the line power
disconnect to the unit.
CHECKING SYSTEM CHARGE
This condensing unit must only be used with the matching
thermostatic expansion valve kit listed in the tabular data
sheet. The best way to check the system charge is by check-
ing the system subcooling during the second stage of opera-
tion.
SERVICING AND VERIFY:
For 2nd stage (2 cylinder) operation, the recommended sub-
cooling is 15°F for all models. For 1st stage (1 cylinder) oper-
ation, the recommended subcooling is 10F for all models.
1.
Set the system running in the second stage (2 cylinder
operation) by setting the thermostat at least 6°F below
the room temperature. Short the “TEST” pin to bypass
the 5 minute anti-short cycle timer if necessary. See Fig-
ure 8.
2.
Operate the system for a minimum of 15 to 20 minutes.
3.
Refer to the tabular data sheet for the recommended air-
flow and verify this indoor air flow (it should be about 400
SCFM per ton).
4.
Measure the liquid refrigerant pressure P and tempera-
ture T at the service valve.
5.
Calculate the saturated liquid temperature ST from Table
1.
6.
Subcooling temperature TC = Saturated Temperature ST
Liquid temp T.
Example:
The pressure P and temperature T measured at
the outdoor unit service port is 220 Psig and 95°F. From Table
1 the saturated temperature for 220 Psig is 108. The subcool-
ing temperature TC = 108 - 95 = 13°F.
The recommended subcooling level should be about 15+/
3°F for all models. Add charge if the calculated subcooling
temperature TC in step 6 is lower than the recommended
level. Remove and recover the refrigerant if the subcooling
Temperature TS is higher than the recommended level.
It is unlawful to knowingly vent, release or dis-
charge refrigerant into open air. It is necessary to
recover the refrigerant during any repair or instal-
lation of the system.
Refrigerant charging should only be carried out
by a qualified air conditioning contractor.
Table 1: R-22 SATURATION TEMPERATURE
ST
1
P
2
1.
ST = Saturated Temperature
2.
P = Pressure
90
168
91
171
92
174
93
176
94
179
ST
P
95
182
96
185
97
187
98
190
99
193
ST
P
100
196
101
199
102
202
103
205
104
208
ST
P
105
211
106
214
107
217
108
220
109
223
ST
P
110
226
111
229
112
233
113
236
114
239
ST
P
115
243
116
246
117
250
118
253
119
256
ST
P
120
260
121
263
122
267
123
271
124
274
ST
P
125
278
126
282
127
285
128
289
129
293
ST
P
130
297
131
301
132
305
133
309
134
313
