265485-XTG-B-1208
Johnson Controls Unitary Products
7
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Gas Heat Propane Conversion Kit
- This kit converts a
gas-fired heater from natural gas to propane. It contains
the main burner orifices and gas valve replacement
springs.
•
Gas Piping Kit
- Contains pipe nipples, fittings and gas
cock required for gas supply connection with external
shut off.
•
Electric Heaters
- The electric heaters range from 9 kW
to 54kW and are available in all the voltage options of the
base units. All heaters are dual staged. Cooling units
include an adapter panel for easy installation of the elec-
tric heaters. Necessary hardware and connectors are
included with the heaters. All heaters are intended for
single point power supply.
•
Low Limit / Compressor Lockout Kit
1.
Compressor Lockout (CLO):
To prevent mechani-
cal (compressorized) operation of the unit during
cold outdoor conditions where there is a risk of
returning liquid refrigerant back to the compressors.
2.
Low Limit Control (LLC):
To prevent the supply air
from dropping below a specified setpoint by utilizing
the units first stage heating means when there is a
demand for cooling during cold outside conditions.
•
Metal Frame Filter Kit -
Metal frame with polyester filter
medium.
•
Permanent Filters
- Permanent filters are available.
•
Roof Curbs
- The roof curbs have insulated decks and
are shipped disassembled The roof curbs are available
in 8” (203 mm) and 14” (356 mm) heights. For applica-
tions with security concerns, burglar bars are available
for the duct openings of the roof curbs.
•
Roof Curb Transition
- Single Piece Adapter (10” (254
mm) High) - Roof curbs for transitioning from Sunline™
units to Predator
®
Magnum. Fits 7.5 to 12.5 Sunline™
roof curbs only.
•
Burglar Bars
- Mount in the supply and return openings
to prevent entry into the duct work.
•
Thermostat
- The units are designed to operate with 24-
volt electronic and electro-mechanical thermostats. All
units (with or without an economizer) operate with two-
stage heat/two-stage cool or two-stage cooling only ther-
mostats, depending upon unit configuration.
REHEAT MODE SEQUENCE OF OPERATION
The reheat control board allows the user to select two differ-
ent modes of operation via a jumper connection on the
board. (See Figure 2.) Each mode is described below. Refer
to Figures 2 and 3 when reading this section.
“NORMAL” MODE
When the reheat control board (RCB) detects a need for
dehumidification (24VAC) at "HUM" via the field supplied
dehumidistat connected to RHTB-1 and RHTB-2 and there is
not a call for cooling, it energizes the hot gas relay (HGR),
which energizes the 3-way valve (SOL 3), the condenser coil
valve (SOL 2), and de-energizes the reheat coil bleed valve
(SOL 1). The Y1 signal is passed to the unit control board
(UCB), which engages circuit # 1, resulting in circuit #1
reheat mode operation.
When the room thermostat calls for first stage cooling, with or
without a call for dehumidification, the RCB senses a signal
through "Y1", de-energizing the HGR, which de-energizes
SOL 3 and SOL 2 and energizes SOL 1, engaging circuit #1,
resulting in circuit #1 cooling mode operation.
When the room thermostat calls for second stage cooling, the
RCB senses a signal through "Y1" & "Y2" and engages circuit
#1 and circuit #2 in cooling mode.
Indoor blower operation is initiated upon a call for first stage
cooling, second stage cooling or dehumidification.
Anytime there is a call for 2 stages of cooling, the unit will not
operate in the reheat mode, even if there is a call for dehu-
midification at "HUM".
The unit will not operate in the reheat mode if there is any call
for heating.
On units with economizers, the unit will not operate in the
reheat mode if there is a call for cooling and the economizer
is operating as first stage of cooling.
All safety devices function as previously described.
"ALTERNATE” MODE
When the RCB detects a need for dehumidification (24VAC)
at "HUM" via the field supplied dehumidistat connected to
RHTB-1 and RHTB-2, and there is not a call for cooling, it
energizes the HGR, which energizes the SOL 3, SOL 2, and
de-energizes SOL 1. The unit then operates with circuit #1 in
reheat mode and circuit #2 in cooling mode.
When the room thermostat calls for first stage cooling while
there is still a call for dehumidification, no operational change
is made. The call for cooling is ignored and the unit continues
to operate with circuit #1 in reheat mode and circuit #2 in
cooling mode.
When the room thermostat calls for second stage cooling, the
RCB senses a signal through "Y1" and "Y2" and de-ener-
gizes the HGR, which de-energizes SOL 3 and SOL 2, and
energizes SOL 1. Both circuits operate in the cooling mode.
Indoor blower operation is initiated upon a call for first stage
cooling, second stage cooling or dehumidification.
Anytime there is a call for 2 stages of cooling, the unit will not
operate in the reheat mode, even if there is still a call for
dehumidification at "HUM".
The unit will not operate in the reheat mode if there is any call
for heating.
All safety devices function as previously described.