Product Brochure

4
6-175.7
DESIGN FEATURES - ALL MODELS
M Power Exhauster (STD)
All units are supplied with a round vent pipe and
combustion air inlet pipe connections.
N Pressure Switch (STD)
An automatic reset vent pressure switch is supplied on
all units and is designed to prevent operation of the main
burner in the event there is restricted venting of flue
products. This restriction may occur due to an improper vent
diameter, long vent runs, un-approved vent terminal, high
winds, high negative pressure within space, etc. After the
cause of the restriction has been corrected, the pressure
switch will reset automatically.
O Integrated Direct Spark Control Board (STD)
The integrated direct spark ignition control combines all
furnace control functions. The integrated board provides
digital control of the air mover, inducer, ignition, gas valve
and flame sense as well as monitoring the safety circuit at
all times. The board includes LED diagnostics for trouble
shooting and a fused power supply.
P Gas Valve - (See Table 12.2)
a) Single Stage Gas Valve - (STD)
The main gas valve is factory installed on the unit
heater gas train. The main gas valve provides regulator,
main gas, and manual shutoff functions. The valve is
redundant and provides 100% shut off.
b) Two Stage Gas Valve - (OPT)
The two-stage gas valve is factory installed on the unit
heater gas train. The two stage gas valve provides the
regulator, main gas (100% and 50% fire), and manual
shutoff functions. The valve is redundant and provides
100% shut off.
Q Control Step Down Transformer - (STD)
The control step down transformer is located in the
electrical junction box. The transformer is used to step
down from 115V to 24V for the gas controls, fan delay
relay, field supplied motor starter, etc. An additional field
installed transformer is required if the supply voltage
is 208V, 230V, 460V, or 575V. To determine the control
transformer supplied as well as any accessory/field supplied
transformers required, refer to Table 12.1
R Flame Sensor (hidden) - (STD)
Remote flame sensor verifies ignition of all burners,
monitors the flame signal and communicates with the
integrated circuit board.
S Flame Roll Out Switch (HDS/HDC models only) - (STD)
Flame roll out switches are mounted near the burners and
will shut off the gas supply in the event of an unsafe flame
roll out condition.
T High Limit Switch (hidden) - (STD)
The limit control is mounted in the air stream and will shut
off the gas supply in the event of overheating.
U Direct Spark Igniter (hidden) - (STD)
Provides spark for direct ignition of the burners.
V Gas Pipe Connection - (STD)
Easy access to factory installed gas pipe connection
stubbed to outside of unit casing.
Figure 4.1 - Factory Mounted Standard and Optional Features
5
2
1
4
3
9
6
4
10
1
2
3
5
9
7
6
8
10
13
8
8
Models HDS/HDC (30-125MBH) Models PTS/BTS (150-400MBH)