Installation Guide
41
GAS SUPPLY PRESSURE MEASUREMENT
Before placing a gas furnace or any gas appliance in opera-
tion, verify that the gas piping, gas fittings and all gas com-
ponents are safe and free of leaks by means of an electronic
combustible gas indicator and a gas meter dial test. Combus-
tible gas indicators must be calibrated and verified at inter-
vals prescribed by the instrument manufacturer.
The line pressure supplied to the gas valve must be within the range specified in the Inlet Gas Supply Pressure table. The supply
pressure can be measured at the gas valve inlet pressure tap or at a hose fitting installed in the gas piping drip leg. The supply
pressure must be measured with the burners operating. To measure the gas supply pressure, use the following procedure:
1. Turn OFF gas to furnace at the manual gas shutoff valve external
to the furnace.
2. Connect a calibrated water manometer (or appropriate gas
pressure gauge) at either the gas valve inlet pressure tap or the
gas piping drip leg. See Honeywell VR9205R gas valve figure for
location of inlet pressure tap.
NOTE: If measuring gas pressure at the drip leg or Honeywell VR9205R
gas valve, a field-supplied hose barb fitting must be installed prior to
making the hose connection.
3. Turn ON the gas supply, check for leaks and operate the furnace
and all other gas consuming appliances on the same gas supply
line.
NOTE: To bring furnace up to High Fire, see instructions for
field test mode in GAS MANIFOLD PRESSURE MEASUREMENT
section.
4. Measure furnace gas supply pressure with burners firing. Supply
pressure must be within the range specified in the Inlet Gas Supply
Pressure table.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
Inlet Gas Supply Pressure
CAUTION
T
O
PREVENT
UNRELIABLE
OPERATION
OR
EQUIPMENT
DAMAGE
,
THE
INLET
GAS
SUPPLY
PRESSURE
MUST
BE
AS
SPECIFIED
ON
THE
UNIT
RATING
PLATE
WITH
ALL
OTHER
HOUSEHOLD
GAS
FIRED
APPLIANCES
OPERATING
.
Inlet
Pressure
Tap
1/8 NPT
2-PIN
POWER
CONNECTOR
i
M
a
n
o
m
e
t
e
r
M
a
n
o
m
e
t
e
r
H
o
s
e
O
p
e
n
t
o
A
t
m
o
s
p
h
e
r
e
Figure 49A
A
TMOSPHERE
PORT
DIRECTION
FLOW
PRESSURE
SWITCH
CONNECTION
Honeywell Model VR9205R
Figure 48
Outlet
Pressure
Tap
1/8 NPT
Figure 49B
Honeywell Model VR9205R Connected to Manometer