National Comfort Product CPG41238-U Series Installation manual - Caution
Installation Guide for Comfort Pack (CPG) Units
19
adjustment is necessary, set pressure to correct settings
by turning the regulator screw IN (clockwise) to increase
pressure. Turn regulator screws OUT (counterclockwise) to
decrease pressure. (See Figure 4 on Page 22)
ROUTE THE WIRES SO THAT THEY DO NOT
CONTACT THE FLUE GAS COLLECTION
BOX OR VENTER HOUSING. CONSULT
THE WIRING DIAGRAM SUPPLIED WITH
YOUR HEATER.
IF ANY OF THE ORIGINAL WIRES AS
SUPPLIED WITH THE APPLIANCE MUST
BE REPLACED, IT MUST BE REPLACED
WITH WIRING MATERIAL HAVING A
TEMPERATURE RATING OF AT LEAST
105°C, EXCEPT FOR LIMIT CONTROL,
FLAME ROLLOUT SWITCH AND SENSOR
LEAD WIRES, WHICH MUST BE 150°C.
PLEASE SEE “HAZARD INTENSITY
LEVELS”.
!
CAUTION
Ignition System
This heater is equipped with a direct spark integrated control
system. The system monitors the safety devices and controls
the operation of the blower and venter motors and the gas valve
between heat cycles. It also controls the blower for cooling.
Ignition System Operating Sequence
–
On a call for heat from the thermostat, the system energizes
the venter motor and goes through a 10-second prepurge. The
system verifies that the pressure switch, the high limit and the
flame rollout switch are in the closed state. The gas valve is then
energized and the ignition system provides the high voltage spark
to the electrode to ignite the main burner gas. Burner flame is
electronically sensed by the control upon carry over of flame. (A
separate solid metal probe is used as the flame sensing function.
A low voltage electrical signal is imposed on the metal probe that
is electrically isolated from ground. When the flame impinges
on the flame sensing probe, the flame acts as a conduction path
to ground. The flame rectifies and completes the DC circuit and
the ignition system acknowledges the flame.) The fan motor is
energized by the system after 30 seconds of flame sensing.
After the thermostat has been satisfied, the system de-energizes
the gas valve, the venter motor goes through a 45-second post-
purge and the fan motor remains energized for an additional
time.
NOTE: This is a three trial system. Should the
unit not sense burner flame, two additional
tries will be made. If the unit does not sense
flame in three tries, it will lockout for one hour
before initiating another 3-sequence trial for
ignition. To initiate another trial for ignition
before the one hour elapses requires that
either the thermostat be reset or the power
to the unit be interrupted for 30 seconds. The
user should not continue to try resetting the
system. Contact a qualified service agency.
Combustion Air Proving Switch
The combustion air proving switch is a pressure sensitive switch
that monitors air pressure to ensure that proper combustion
air flow is available. The switch is a single pole/normally open
device that closes when a decreasing pressure is sensed in the
venter housing.
On start-up when the heater is cold, the sensing pressure is at
the most negative level, and as the heater warms up, the sensing
pressure becomes less negative. After the system has reached
equilibrium (about 10 minutes), the sensing pressure levels off.
If a restriction causes the sensing pressure to be outside the
switch setpoint, the pressure switch will function to shut off the
main burner. The main burner will remain off until the system
has cooled and/or the resistance is reduced. The Table below
lists the approximate water column negative pressure readings
and switch setpoints for sea level operating conditions.
.
HEAT MODULE P/N
14208309 14208308 14208303
START-UP COLD
1.0 +/- .1
1.0 +/- .1
1.05 +/- .1
EQUILIBRIUM
.72 +/- .05 .72 +/- .05
.8 +/- .05
SETPOINT “OFF”
.55
.55
.55
SETPOINT “ON”
.65
.65
.65
Limit Switch
All units are equipped with a temperature activated auto reset
limit control. The control is factory set and is non-adjustable.
If the setpoint is reached, the limit control acts to interrupt
the electric supply to the gas valve. This safety device provides
protection in the case of motor failure or lack of airflow due to a
restriction at the inlet or outlet.