SYSTEM START-UP
ENERGIZE CRANKCASE HEATER
This unit is equipped with crankcase heaters for both the lead
and follower compressors. The operation of the crankcase
heater is monitored by means of the control board.
CAUTION: An attempt to start the compressor without at least
8 hours of crankcase heat will damage the com-
pressor.
A warning label with an adhesive back is supplied in the unit
installation instruction packet. This label should be attached to
the field supplied disconnect switch where it will be easily seen.
See below.
In order to energize the crankcase heater:
- Set indoor two stage cooling thermostat to "OFF" position.
- Close the line power disconnect to the unit.
CHECKING SYSTEM CHARGE
The factory charge in the outdoor unit is listed in the Table 5 as
well as unit nameplate and includes enough charge for the unit
and the corresponding indoor evaporator coil. This unit in-
cludes sufficient charge for 15 feet of line sets. Table 6 lists the
refrigerant line charges for additional lengths.
CAUTION:
REFRIGERANT CHARGING SHOULD ONLY BE
CARRIED OUT BY A QUALIFIED AIR CONDI-
TIONING CONTRACTOR.
In order to check whether the unit has the required charge in
the system, follow the procedure described below.
WARNING:DO NOT VENT REFRIGERANT TO THE ATMOS-
PHERE. IT IS NECESSARY TO RECOVER THE
REFRIGERANT DURING ANY REPAIR OR IN-
STALLATION OF THE SYSTEM.
1. Set room thermostat at desired temperature. The thermo-
stat may be energized at first (Y1) stage or second (Y2)
stage. If only the first stage (Y1) is energized, only the lead
compressor will be in operation. Both the compressors will
be in operation if the second stage of thermostat (Y2) is
energized.
Set room thermostat at "COOL" position and fan switch at
"AUTO" or "FAN" position. There is a five minute delay
when the "system control board" is powered for the first
time. Refer to "System Functions" for more information
about time delays.
2. Operate the unit for a minimum of 15-20 minutes before
checking the charge.
3. Verify the desired indoor air handler air flow (CFM).
4. The system charge should be varified with only the lead
compressor running, however it can be also checked with
both the compressors running at the same time at the rated
indoor air handler air flow. However, it is required to estab-
lish the subcooling level at any one condition i.e. either with
the lead compressor running or when both (the lead and
follower) compressors are running.Recommended sub-
cooling temperature is listed in Table 3.
MODEL
RECOMMENDED SUBCOOLING °F
LEAD
COMPRESSOR
ONLY
LEAD + FOLLOWER*
(BOTH)
COMPR. RUNNING
H1DS036 10 18
H1DS048 10 18
H1DS060 10 18
*Lead compressor is designated / labeled as the # 1 com-
pressor. Follower compressor is the # 2 compressor.
TABLE 3 - RECOMMENDED SUBCOOLING
LIQUID
PRESSURE
(PSIG) @
SERVICE
PORT
Required Subcooling Temp. ° F
LIQUID
PRESSURE
(PSIG) @
SERVICE
PORT
Required Subcooling Temp. ° F
5 10 12 15 20 5 10 12 15 20
Liquid Line Temperature ° F Liquid Line Temperature ° F
139 73 68 66 63 58 264 116 111 109 106 101
146 76 71 69 66 61 271 117 112 110 107 102
153 79 73 71 68 63 276 120 115 113 110 105
161 82 77 75 72 67 285 122 117 115 112 107
166 85 90 88 85 80 301 126 121 119 116 111
179 89 84 82 79 74 309 127 122 120 117 112
187 92 87 85 82 77 317 130 125 123 120 115
196 95 90 88 85 80 325 132 127 125 122 117
202 97 92 90 87 82 333 134 129 127 124 119
208 99 94 92 89 84 342 136 131 129 126 121
220 103 98 96 93 88 350 138 133 131 128 123
229 106 101 99 96 91 359 140 135 133 130 125
236 108 103 101 98 93 368 142 137 135 132 127
246 111 106 104 101 96 377 144 139 137 134 129
256 114 109 107 104 99 386 146 141 139 136 131
TABLE 4 - SUB-COOLING CHART
IMPORTANT
IF POWER HAS BEEN OFF FOR 8 HOURS OR LONGER,
DISCONNECT SWITCH MUST BE TURNED ON 8 HOURS
BEFORE THERMOSTAT IS SET TO “HEAT”,"COOL" OR
“AUTO”
035-03095.
550.37-N1Y
Central Environmental Systems 9
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