Gas Manifold Pressurem; Easurement And Djustment - Goodman MVC8 Installation Instructions Manual

Regulator
Vent
Gas Valve On/Off
Selector Switch
Honeywell Model VR9205 (Two-Stage)
i
Outlet Pressure Tap
1/8 NPT
Honeywell Model VR9205 Connected to Manometer
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
boss or the gas piping drip leg. See Honeywell VR9205
gas valve figure or White-Rodgers 36G54 gas valve figure
for location of inlet pressure boss.
NOTE: If measuring gas pressure at the drip leg or Honeywell
VR9205 gas valve, a field-supplied hose barb fitting must be
installed prior to making the hose connection. If using the inlet
pressure boss on the White-Rodgers 36G54 gas valve, then
use the 36G Valve Pressure Check Kit, Goodman Part No.
0151K00000S.
3. Turn ON the gas supply and operate the furnace and all
other gas consuming appliances on the same gas supply
line.
4. Measure furnace gas supply pressure with burners firing.
Supply pressure must be within the range specified in
the Inlet Gas Supply Pressure table.
High Fire
Regulator
Natural Gas
Adjust
Propane Gas
If supply pressure differs from table, make the necessary ad-
justments to pressure regulator, gas piping size, etc., and/or
consult with local gas utility.
5. Turn OFF gas to furnace at the manual shutoff valve and
disconnect manometer. Reinstall plug before turning on
gas to furnace.
Low Fire
6. Turn OFF any unnecessary gas appliances stated in
Regulator
Adjust
step 3.
Common
Terminal(C)
High Fire Coil
Terminal (HI)
Low Fire Coil
Terminal (LO)
Inlet Pressure Tap
1/8 NPT
G
AS
T
O PREVENT
GAS
PLATE
THE
Only small variations in gas pressure should be made by ad-
justing 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.
1. Turn OFF gas to furnace at the manual gas shutoff valve
external to the furnace.
2. Turn off all electrical power to the system.
3. Outlet pressure tap connections:
a. Honeywell VR9205 valve: Remove the outlet pressure
b. White-Rodgers 36G54 valve: Back outlet pressure test
26
INLET GAS SUPPLY PRESSURE
Minimum: 4.5" w.c.
Minimum: 11.0" w.c.
Gas Line
Gas
Shutoff
Valve
Gas Line
To Furnace
Drip Leg Cap
With Fitting
Manometer Hose
Measuring Inlet Gas Pressure (Alt. Method)
M P M
ANIFOLD RESSURE EASUREMENT AND
CAUTION
UNRELIABLE OPERATION
MANIFOLD PRESSURE MUST BE
. O
NLY MINOR ADJUSTMENTS
GAS VALVE PRESSURE REGULATOR
boss plug. Install an 1/8" NPT hose barb fitting into
the outlet pressure tap.
screw (inlet/outlet pressure boss) out one turn
(counterclockwise, not more than one turn).
Maximum: 10.0" w.c.
Maximum: 13.0" w.c.
Open To
Atmosphere
Manometer
A
DJUSTMENT
,
OR EQUIPMENT DAMAGE THE
AS SPECIFIED ON THE UNIT RATING
SHOULD BE MADE BY ADJUSTING
.