Lennox LCH092H Unit Information page 62

N-Factory Installed-Hot Gas Reheat (option)
General
Hot Gas Reheat units provide a dehumidifying mode of op­
eration. These units contain a reheat coil adjacent to and
downstream of the evaporator coil. Reheat coil solenoid
valve, L14, routes hot discharge gas from the compressor
to the reheat coil. Return air pulled across the evaporator
coil is cooled and dehumidified; the reheat coil adds heat
to supply air. See figure 32 for reheat refrigerant routing
and figure 33 for standard cooling refrigerant routing.
L14 Reheat Coil Solenoid Valve
When Unit Controller input (Unit Controller J298-5 or
J299-8) indicates room conditions require dehumidifi­
cation, L14 reheat valve is energized (Unit Controller
P269-3) and refrigerant is routed to the reheat coil.
Reheat Setpoint
Reheat is factory-set to energize when indoor relative hu­
midity rises above 60% (default). The reheat setpoint can
be adjusted by changing Unit Controller Settings - Control
menu. A setting of 100% will operate reheat from an energy
management system digital output. The reheat setpoint
can also be adjusted using an optional Network Control
Panel (NCP).
Reheat will terminate when the indoor relative humidity falls
3% (57% default) or the digital output de-energizes. The re­
heat deadband can be adjusted at Settings - Control menu.
Check-Out
Test Hot Gas Reheat operation using the following proce­
dure.
1 Make sure reheat is wired as shown in wiring section.
2 Make sure unit is in local thermostat mode.
3 Select Unit Controller Service - Test.
The blower and compressor 1 (reheat) should be operat­
ing. Reheat mode will be appear on the Unit Controller dis­
play.
4 Deselect Unit Controller Service - Test.
Compressor 1 (reheat) and blower should de-energize.
Default Reheat Operation
Reheat Operation - Two Cooling Stages - Default
T'stat and Hu­
midity Demands
Reheat Only
Reheat & Y1
Reheat & Y1 & Y2
*If there is no reheat demand and outdoor air is suitable,
free cooling will operate.
**If there is no reheat demand and outdoor air is suitable,
free cooling and compressor 1 will operate.
Page 62
TABLE 25
Operation
Compressor 1 Reheat
Compressor 1 Reheat &
Compressor 2 Cooling*
Compressor 1 Cooling &
Compressor 2 Cooling**