Checksand Adjustments - ICP 8MPT Installation Insrtuctions

• With a parallel flow arrangement, the dampers or other
means used to control flow of air shall be adequate to pre-
vent chilled air from entering the furnace. Chilled air going
through the furnace could cause condensation and shorten
furnace life. Dampers (purchased locally) can be either au-
tomatic or manual. Manually or automatically operated
dampers MUST be equipped with a means to prevent fur-
nace and air conditioning operation, unless damper is in
the full heat or cool position.
• Installation of locking-type dampers is recommended in all
branches, or in individual ducts to balance system's air
flows.
• Non-combustible, flexible duct connectors are recom-
mended for return and supply connections to furnace.
• If air return grille is located close to the fan inlet, install at
least one 90 ° air turn between fan and inlet grille to reduce
noise.
• Ductwork installed in attic or exposed to outside tempera-
tures requires a minimum of 2" (50.8mm) of insulation with
outdoor type vapor barrier.
• Ductwork installed in an indoor unconditioned space re-
quires a minimum of 1" (25.4mm) of insulation with indoor
type vapor barrier.
12. Checks and Adjustments
Startup
NOTE: Refer to startup procedures in the Users Information
Manual.
ELECTRICAL SHOCK, FIRE, OR EXPLOSION
HAZARD
Failure to followthis warning could result in injury,
death, and/or property damage.
If any sparks, odors or unusual noises occur,
immediately shut OFF gas and power to furnace.
Check for wiring errors or obstruction to blower.
Gas Supply Pressure
Gas supply pressure should be within minimum and maximum
FIRE OR EXPLOSION HAZARD
Failure to turn OFF gas at shut off before
connecting manometer could result in personal
injury, death and/or property damage.
Turn OFF gas at shut off before connecting
manometer.
1. With gas OFF, connect manometer to manifold pressure
tap on the outlet of gas control valve. See Figure 33. Use a
manometer with a 0 to 12 in wc (0 to 2989 Pa) range.
2. Turn gas ON. Operate the furnace on High Heat by using a
jumper wire on the R to Wl & W2 thermostat connections
on the furnace control board.
3. Remove manifold pressure adjustment screw cover on fur-
nace gas control valve. Turn adjusting screw counterclock-
wise to decrease the manifold pressure and clockwise to
increase pressure. See Figure 33.
NOTE: Adjustment screw cover MUST be replaced on gas control
valve before reading manifold pressure and operating furnace.
values listed on rating plate. Pressures are usually set by gas sup-
pliers.
ManifoldGas Pressure Adjustments
(High and Low Heat)
NOTE: Make adjustment to manifold pressure with burners oper-
ating.
Typical Gas Control Valve Honeywell
Regulator
4. Set manifold pressure to value shown in Table 5 or Table 4.
5. Operate the furnace on Low Heat by using a jumper wire on
the R to Wl thermostat connections on the furnace control
board.
Note: The SWl DIP switch #3 should be in the on position
to set the Low Heat manifold pressure. (See wiring dia-
gram.)
6. Repeat steps 3 and 4 for Low Heat operation.
7. When the manifold pressures are properly set, replace the
adjustment screw covers on the gas control valve.
8. Remove the jumper wires from the thermostat connections
on the furnace control board. Remove manometer connec-
tion from manifold pressure tap, and replace plug in gas
valve.
9. Return SWl DIP switch #3 to previous setting.
25-24-98a
OUTLET
Pressure
Tap 1/8"
10. Check for leaks at plug.
Natural Gas Input RatingCheck
The gas meter can be used to measure input to furnace. Check
with gas supplier for actual BTU content.
1. Turn OFF gas supply to all appliances other than furnace
and start furnace. Use jumper wire on R to Wl and W2 for
High Heat.
2. Time how many seconds it takes the smallest dial on the
gas meter to make one complete revolution. Refer to Ex-
ample.
44101 202301
Specifications are subject to change without notice
30