Cooling Start-Up - Lennox LHT078H Installation Instructions Manual

Cooling Start-Up

IMPORTANT-The crankcase heater must be energized
for 24 hours before attempting to start compressor. Set
thermostat so there is no demand to prevent
compressors from cycling. Apply power to unit.
A-Start-Up
1- Initiate full load cooling operation using the following
mobile service app menu path:
RTU MENU > SERVICE > COMPONENT TEST > COOLING
> COOLING STAGE 3
2- Refer to Cooling Operation section for cooling
start-up.
3- Units have two refrigerant circuits. See figure 19 or
figure 20.
4- Each refrigerant circuit is charged with R410A
refrigerant. See unit rating plate for correct
amount of charge.
5- Refer to Refrigerant Check and Charge section for
proper method to check refrigerant charge.
REFRIGERANT STAGES - TWO FANS
LHT/LDT078, 092, 102H:
Two-Stage Thermostat/Control:
Y1 Demand = Outdoor Fan 1 HIGH Speed, Fan 2 OFF
Y2 Demand = Outdoor Fans 1 & 2 HIGH Speed
W1 Demand (Heat Pump Heating) =
Outdoor Fans 1 & 2 HIGH Speed
Three-Stage Thermostat/Control:
Y1 Demand = Outdoor Fan 1 LOW Speed, Fan 2 OFF
Y2 Demand = Outdoor Fans 1, 2 MEDIUM Speed
Y3 Demand = Outdoor fans 1, 2, HIGH Speed
W1 Demand (HP Heating)=
Outdoor Fans 1, 2 High Speed
OUTDOOR COIL
STAGE 2
INDOOR COIL
STAGE 2
2
1
FIGURE 19
OUTDOOR
FAN 2
OUTDOOR
FAN 1
B5
B4
OUTDOOR COIL
STAGE 1
INDOOR COIL
STAGE 1
REFRIGERANT STAGES - THREE FANS
Two-Stage Thermostat/Control:
Y1 Demand = Outdoor Fans 1, 2, & 3 MEDIUM Speed
Y2 Demand = Outdoor Fans 1, 2 & 3 HIGH Speed
W1 Demand (Heat Pump Heating) =
Three-Stage Thermostat/Control:
Y1 Demand = Outdoor Fans 1, 2, & 3 LOW Speed
Y2 Demand = Outdoor Fans 1, 2, & 3 MEDIUM Speed
Y3 Demand = Outdoor Fans 1, 2, & 3 HIGH Speed
W1 Demand (HP Heating)=
INDOOR COIL
STAGE 2
2
B-R410A Refrigerant
Units charged with R410A refrigerant operate at much
higher pressures than R22. The expansion valve and
liquid line drier provided with the unit are approved for use
with R410A. Do not replace them with components
designed for use with R22.
R410A refrigerant is stored in a pink cylinder.
Manifold gauge sets used with systems charged with
R410A refrigerant must be capable of handling the higher
system operating pressures. The gauges should be rated
for use with pressures of 0-800 on the high side and a low
side of 30" vacuum to 250 psi with dampened speed to
500 psi. Gauge hoses must be rated for use at up to 800
psi of pressure with a 4000 psi burst rating.
Mineral oils are not compatible with R410A. If oil
must be added, it must be a polyol ester oil.
Page 19
LHT/LDT122, 150H:
Outdoor Fans 1, 2, 3 HIGH Speed
Outdoor Fans 1, 2, & 3 HIGH Speed
OUTDOOR COIL
OUTDOOR
STAGE 2
FAN 2
B5 B5
B21 B4
1
INDOOR COIL
STAGE 1
FIGURE 20
IMPORTANT
OUTDOOR
FAN 3
OUTDOOR
FAN 1
OUTDOOR COIL
STAGE 1