17
G
aS
S
UPPly
P
RESSURES
& R
EGUlatoR
a
djUStMEntS
WARNING
S
HoUld
ovERHEatInG
occUR
oR
tHE
GaS
SUPPly
faIl
to
SHUt
off
,
tURn
off
tHE
ManUal
GaS
SHUtoff
valvE
ExtERnal
to
tHE
UnIt
bEfoRE
tURnInG
off
tHE
ElEctRIcal
SUPPly
.
WARNING
t
o
avoId
PRoPERty
daMaGE
,
PERSonal
InjURy
oR
dEatH
,
do
not
fIRE
GaS
UnIt
WItH
flUE
box
covER
REMovEd
.
notE: E
xcEPt
dURInG
bRIEf
PERIodS
WHEn
GaS
PRESSURES
aRE
bEInG
MEaSUREd
by
qUalIfIEd
SERvIcE
PERSonnEl
,
tHE
fURnacE
accESS
PanEl
MUSt
alWayS
bE
SEcUREd
In
PlacE
WHEn
tHE
fURnacE
IS
In
oPERatIon
. a
n
InSPEctIon
PoRt
In
tHE
accESS
PanEl
IS
PRovIdEd
to
MonItoR
tHE
flaME
.
The first step in checking out the gas-fired furnace is to test
the gas supply piping to the unit for tightness and purge the
system of air using methods outlined in the latest edition of
the National Fuel Gas Code ANSI Z223.1 / NFPA 54. Verify
that the disconnect switch is in the “OFF” position. A soapy
water solution should be used to check for gas leaks.
Since the unit is subject to considerable jarring during
shipment, it is extremely important that all gas connections
and joints be tested for tightness. Gas piping downstream
from the unit inlet should be checked for leaks during the
subsequent sequence check.
The supply gas pressure should be adjusted to 7.0” w.c.
on natural gas and 11” to 13.0” w.c. on LP gas with the
gas burners operating. If there is more than one unit on
a common gas line, the pressures should be checked
with all units under full fire. A supply pressure tap is
provided on the upstream side of the gas valve. A manifold
pressure tap is provided on the manifold side of the gas
valve. The normal manifold pressure for High fire is 3.5”
w.c. on natural gas and 10.0” w.c. for propane gas. Low
fire natural gas 2.0” w.c., 6.0” w.c. low fire propane gas.
Minimum gas supply pressure is 5.0” w.c. for natural gas
and 11.0” w.c. for propane gas.
Do not attempt adjustment of the built-in pressure regulator
unless the supply pressure is at least 5.0” w.c. on natural
gas or 11.0” w.c. on propane gas.
FLAME SENSOR
IGNITION ELECTRODE
flaME
SEnSoR
and
IGnItIon
ElEctRodE
locatIon
5 GPG1660140M41 140,000
6
41
54
Ton
Model
L.P.
Orifice
Drill #
High Fire
Rate
BTU/HR
Number
of
Burners
N.G.
Orifice
Drill #
HEat
ExcHanGER
and
bURnER
oRIfIcE
SPEcIfIcatIonS
notE: G
aS
aPPlIancES
locatEd
MoRE
tHan
2000
fEEt
abovE
SEa
lEvEl
MUSt
bE
dERatEd
4%
PER
1000
fEEt
of
total
ElEvatIon
and
tHat
vaRIancE
In
GaS
HEatInG
valUE
and
SPEcIfIc
GRavIty
REqUIRE
cHanGE
In
ManIfold
PRESSURE
to
obtaIn
RatInG
,
It
IS
MandatoRy
tHat
tHE
InPUt
bE
adjUStEd
at
tHE
InStallatIon
SItE
.
a
ll
InStallatIonS
SHoUld
bE
MadE
aS
oUtlInEd
In
tHE
latESt
EdItIon
of
tHE
n
atIonal
f
UEl
G
aS
c
odE
anSI Z223.1,
SEctIon
“P
RocEdURES
t
o
b
E
f
olloWEd
t
o
P
lacE
a
n
a
PPlIancE
In
o
PERatIon
”. R
EfER
alSo
to
tHE
“U
SER
’
S
I
nfoRMatIon
M
anUal
”
SUPPlIEd
WItH
tHE
UnIt
foR
addItIonal
InfoRMatIon
on
tHE
GaS
fURnacE
.
G
aS
S
UPPly
a
nd
M
anIfold
c
HEck
Gas supply pressure and manifold pressure with the
burners operating must be as specified on the rating plate.
G
aS
I
nlEt
P
RESSURE
c
HEck
Gas inlet pressure must be checked and adjusted in
accordance to the type of fuel being consumed.
W
ItH
P
oWER
a
nd
G
aS
o
ff
:
1. Connect a manometer to the inlet pressure tap of the
gas valve.
Inlet gas pressure can also be measured by removing the
cap from the dripleg and installing a predrilled cap with a
hose fitting.
W
ItH
P
oWER
a
nd
G
aS
o
n
:
2. Put unit into heating cycle and turn on all other gas
consuming appliances.
