Unit Components - Modine Manufacturing PTC Installation And Service Manual

unIT ComPonenTs

Table 23.1 - Control options
Control description
single-stage, direct spark Ignition, 100% shut-off with Continuous retry
Utilizes a single-stage combination gas control with ignition control.
Gas is lit with a direct spark igniter on call for heat.
figure 23.1 - factory mounted standard features
15
14
13
12
➀ Power exhauster
All units are supplied with a round vent pipe and
combustion air inlet pipe connections.
➁ Pressure switch
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.
➂ Control step down Transformer
The control step down transformer is located in the electrical
junction box. The transformer is used to step the voltage
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 required accessory transformers,
refer to Tables 17.1-17.4.
➃ Integrated direct spark Control Board
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 sensing as well as monitoring the safety circuit at
all times. The board includes LED diagnostics for trouble
shooting and a fused power supply. Ignition control is 100%
shut-off with continuous retry.
➄ flame sensor
Remote flame sensor verifies ignition of all burners,
monitors the flame signal and communicates with the
integrated circuit board.
16 ➀
➁
➈
11 10
Control
Code no.
11
21
➂
➉ C ondensate drain overflow switch
Shuts down gas controls if condensate is not properly
draining from the unit.
gas Pipe Connection
11
Easy access to factory installed gas pipe connection
stubbed to outside of unit casing.
Condensate drain Connection
12
Easy access to factory installed condensate drain pipe
connection stubbed to outside of unit casing.
Combustion Air Inlet Pipe Connection
13
Simple connection for combustion air inlet piping.
vent Pipe Connection
14
Rubber exhaust coupling with clamp for easy connection of
PVC vent system.
fan guard
15
Propeller units may be equipped with an optional (standard
on size 110 and smaller) finger proof fan guard for added
protection. If ordered, the finger proof fan guard is installed at
the factory in place of the standard fan guard.
Contractor Convenience Package
16
External junction box features simple connection of supply
power wiring internally, thermostat wiring to terminals
externally, an On/Off switch, a single 115V outlet for
connection of an external condensate pump, and status
indicator lights to display the operational state of the unit.
Horizontal Air deflector Blades (not shown in figure 23.1)
17
Factory mounted on the discharge of the unit, the blades can
be adjusted to provide horizontal (up and down) delivery
control of the heated air. Vertical deflector blades are
available as a field installed accessory.
6-563.7
service Thermostat Type of
voltage voltage gas
115V 24V Natural
115V 24V Propane
➅ single stage gas valve
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
➃
redundant and provides 100% shut
off. Natural gas is Control Code 11,
➄
propane gas is Control Code 21.
➆ flame roll out switch (size 110
and smaller only) (hidden)
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.
➅
➇ direct spark Igniter
Provides spark for direct ignition of
the burners.
➇
➈ High limit switches
One limit control is mounted in the
air stream and will shut off the gas
supply in the event of overheating.
The other limit control is mounted
on the power exhauster housing
and will shut off the gas supply in
the event of overheating flue gas
temperatures.
23