GMEC96 Installation Manual
35
the hose connection. If using the inlet pressure tap on the
3. Turn ON the gas supply and operate the furnace and all
other gas consuming appliances on the same gas supply
line.
Inlet Gas Supply Pressure table.
-
justments to pressure regulator, gas piping size, etc., and/or
consult with local gas utility.
disconnect manometer. Reinstall plug before turning on
gas to furnace.
6. Turn OFF any unnecessary gas appliances stated in step
3.
T
O
PREVENT
UNRELIABLE
OPERATION
OR
EQUIPMENT
DAMAGE
,
THE
GAS
MANIFOLD
PRESSURE
MUST
BE
AS
SPECIFIED
ON
THE
UNIT
RATING
PLATE
. O
NLY
MINOR
ADJUSTMENTS
SHOULD
BE
MADE
BY
ADJUSTING
THE
GAS
VALVE
PRESSURE
REGULATOR
.
CAUTION
Only small variations in gas pressure should be made by adjusting
the gas valve pressure regulator. The manifold pressure must be
measured with the burners operating. To measure and adjust
the manifold pressure, use the following procedure.
external to the furnace.
3. Outlet pressure tap connections:
test screw (inlet/outlet pressure tap) out one turn
(counterclockwise, not more than one turn).
4. Attach a hose and manometer to the outlet pressure tap
5. Turn ON the gas supply.
contacts to provide a call for low stage heat.
7. Measure the gas manifold pressure with burners
Manifold
Gas Pressure table shown below.
Range Nominal
Natural Low Stage 1.6 - 2.2" w .c. 1.9" w .c.
High Stage 3.2 - 3.8" w .c. 3.5" w .c.
Propane Low Stage 5.7 - 6.3" w .c. 6.0" w .c.
High Stage
9.7 - 10.3" w .c.
10.0" w .c.
Manifold Gas Pressure
Gas
8. Remove regulator cover screw from the low (LO) outlet
pressure regulator adjust tower and turn screw clockwise
to increase pressure or counterclockwise to decrease
pressure. Replace regulator cover screw.
provide a call for high stage heat.
10. Remove regulator cover screw from the high (HI)
outlet pressure regulator adjust tower and turn screw
clockwise to increase pressure or counterclockwise to
decrease pressure. Replace regulator cover screw.
system.
12. Remove the manometer hose from the hose barb
13. Replace outlet pressure tap:
in to seal pressure port (clockwise, 7 in-lb minimum).
14. Turn on electrical power and gas supply to the system.
the valve.
Using a leak detection solution or soap suds, check for leaks
at outlet pressure tap plug (Honeywell valve) or screw
For gas to gas conversion, consult your dealer for
appropriate conversion.
INLET OUTLET
Gas Valve On/Off
Selector Switch
Figure 39A
Inlet
Pressure
Boss
Low Fire
Regulator
Adjust
M
a
n
o
m
e
t
e
r
M
a
n
o
m
e
t
e
r
H
o
s
e
High Fire Regulator
Adjust
Regulator
Vent
Outlet
Pressure Boss
Open to
Atmosphere
O
n
/
O
f
f
S
w
i
t
c
h
H
ig
h
F
ir
e
C
o
il
T
e
r
m
in
a
l (
H
I
)
C
o
a
x
ia
l
C
o
il
T
e
r
m
in
a
l
(
M
)
Common
Terminal(C)
Figure 39B