National Comfort Product CPG41238-U Series Installation manual - Gas Furnace Specifications
Installation Guide for Comfort Pack (CPG) Units
14
Gas Furnace Specifications
Gas Heat – The cabinet includes a gas furnace with integral
flue duct, direct spark ignition, safety controls, and operating
controls. The installation of the unit and gas piping must be in
accordance with local codes.
Gas Valve Setting 3.5” w.c
.
HEAT MODULE
14208309
14208308
14208303
INPUT BTUH
38,000
51,000
64,000
OUTPUT BTUH
30,400
40,800
51,200
MAXIMUM EXTERNAL
STATIC PRESSURE
.5" W.C.
.5" W.C
.5" W.C
DISCHARGE
TEMPERATURE RISE
RANGE
45°F to 60°F
45°F to 65°F
60°F to 80°F
BLOWER SPEED
SETTING
Med. Low*
(4-Black)
Med. High*
(2-Yellow)
High*
(1-Red)
*See Wiring Diagram on Page 33.
To ensure safe operation and long life of the heat exchanger, the
maximum static pressure and/or maximum temperature rise must not
be exceeded. Operation of the heater at conditions that exceed the
heater’s specifications will void the heat exchanger warranty
MODEL SIZE
38
51
64
ORIFICE SIZE N.G.
31
28
22
ORIFICE SIZE L.P.
49
2.1 mm
41
NOMINAL
TEMPERATURE RISE
52.5°F
55°F
67°F
ALLOWABLE AIR
TEMPERATURE RANGE
140-160
140-160
135-160
CO
2
%- ACCEPTABLE
RANGE
4.5 to 5.2
4.8 to 5.8
4.5 to 5.5
CO AIR FREE - PPM
0 - 200
0 - 200
0 - 200
SENSING COLD
1.05 +/- .1
1.05 +/- .1
1.05 +/- .1
PRESSURE HOT
.8+/- .05
.8+/- .05
.8+/- .05
EFFICIENCY RANGE
81.5% - 82.5%
81.5% - 82.5%
80.1% - 81.1%
STACK TEMPERATURE
245°F- 300°F
245°F- 300°F
270°F- 330°F
Temperature Rise Range Based On Return Air Temperature
Sequence of Operations (Gas Heat)
1. Call for Heat – The thermostat sends a call for heat therefore
energizing the “white” wire to the control board. The control
checks to see that the limit switch is closed and the pressure
switch is open. If the limit switch is open, the control responds as
defined in the “Limit Switch Operation - page 9”. If the pressure
switch is closed, the control will do four flashes on the green
LED and wait indefinitely for the pressure switch to open. If the
pressure switch is open, the control proceeds to (2.) Pre-purge.
2. Pre-purge – The control energizes the venter motor and waits
for the pressure switch to close. If the pressure switch does not
close within 240 seconds of the venter motor energizing, on 3
attempts ,the control green LED will flash two times and will
enter a soft lock out. When the pressure switch is proven closed,
the control begins the pre-purge time. If flame is present any
time while in pre-purge, the pre-purge time is restarted. If flame
is present long enough to cause lockout, the control responds
as defined in “Undesired Flame - page 18”. The control runs the
venter motor for a 20 second pre-purge time, then proceeds to
the (3.) Ignition Trial Period.
3. Ignition Trial Period – The control energizes the spark
and main gas valve. The venter remains energized. If flame is
sensed during the first 16 seconds, the spark is de-energized
and the control proceeds to (4.) Heat Blower On Delay. If flame
has not been sensed during the first 16 seconds, the control
de-energizes the spark output and keeps the gas valve energized
for an additional one second flame proving period. If flame is not
present after the flame proving period, the control de-energizes
the gas valve and proceeds with ignition re-tries as specified in
“Ignition Retry - page 9”. If flame is present, the control proceeds
to the (4.) Heat Blower On Delay
4. Heat Blower On Delay – The control waits for 30 seconds
from the time the gas valve opened and then energizes the
blower motor. The gas valve and venter motor remain energized.
The control proceeds to (5.) Steady Heat.
5. Steady Heat – The control continuously monitors to the
safeties (high limit, roll-out, and pressure) for open switches,
flame sensor for proving, and the thermostat for a call for
heat. When the thermostat call for heat is removed, the control
de-energizes the gas valve and begins (6.) Post-purge and
(7.) Blower Off Delay.
6. Post-purge – The venter motor output remains on for a
45-second post-purge period after the thermostat is satisfied.
7. Blower Off Delay – The blower motor is de-energized after a
blower off delay 90 seconds factory setting (field adjustable, see
page 17 or 50). Timing begins when the thermostat is satisfied.