12
• In the prior two methods above the connector or tubing
must be protected from physical and thermal damage. Alu-
minum alloy tubing and connectors must be coated to pro-
tect against external corrosion when in contact with mason-
ry, plaster or insulation or are subject to repeated wettings
by liquids (water - not rain water, detergents or sewage).
BURNER
DOOR
DRIP
LEG
MANUAL
SHUT-OFF
GROUND JOINT
UNION
TBD
Proper Piping Practice
NOTE:
The unit gas supply entrance is factory sealed with
plugs. Keep plugs in place until gas supply is ready to be
installed. Once ready, replace the plugs with the supplied
grommets and install gas supply line.
g
as
P
iPing
c
hecks
CAUTION
T
O PREVENT PROPERTY DAMAGE OR PERSONAL INJURY DUE TO FIRE, THE
FOLLOWING INSTRUCTIONS MUST BE PERFORMED REGARDING GAS
CONNECTIONS AND PRESSURE TESTING:
•
T
HE UNIT AND ITS GAS CONNECTIONS MUST BE LEAK TESTED BEFORE
PLACING IN OPERATION.
B
ECAUSE OF THE DANGER OF EXPLOSION OR
FIRE, NEVER USE A MATCH OR OPEN FLAME TO TEST FOR LEAKS.
N
EVER
EXCEED SPECIFIED PRESSURES FOR TESTING.
H
IGHER PRESSURE MAY
DAMAGE GAS VALVE AND CAUSE OVERFIRING WHICH MAY RESULT IN
PREMATURE HEAT EXCHANGE FAILURE.
•
T
HIS UNIT AND ITS SHUT-OFF VALVE MUST BE DISCONNECTED FROM
THE GAS SUPPLY DURING ANY PRESSURE TESTING OF THAT SYSTEM AT
TEST PRESSURES IN EXCESS OF 1/2
PSIG
(3.48 K
P
A).
•
T
HIS UNIT MUST BE ISOLATED FROM THE GAS SUPPLY SYSTEM BY
CLOSING ITS MANUAL SHUT-OFF VALVE DURING ANY PRESSURE
TESTING OF THE GAS SUPPLY PIPING SYSTEM AT TEST PRESSURES
EQUAL TO OR LESS THAN 1/2
PSIG
(3.48 K
P
A).
WARNING
T
O AVOID PROPERTY DAMAGE OR PERSONAL INJURY
, BE SURE THERE IS
NO OPEN FLAME IN THE VICINITY DURING AIR BLEEDING.
There will be air in the gas supply line after testing for leaks
on a new installation. Therefore, the air must be bled from
the line by loosening the ground joint union until pure gas is
expelled. Tighten union and wait for five minutes until all gas
has been dissipated in the air. Be certain there is no open
flame in the vicinity during air bleeding procedure. The unit
is placed in operation by closing the main electrical discon-
nect switch for the unit.
PROPANE GAS INSTALLATIONS
WARNING
T
O AVOID PROPERTY DAMAGE, PERSONAL INJURY OR DEATH DUE TO FIRE
OR EXPLOSION CAUSED BY A PROPANE GAS LEAK, INSTALL A GAS
DETECTING WARNING DEVICE.
S
INCE RUST CAN REDUCE THE LEVEL
OF ODORANT IN PROPANE GAS, A GAS DETECTING WARNING DEVICE
IS THE ONLY RELIABLE WAY TO DETECT A PROPANE GAS LEAK.
C
ONTACT A LOCAL PROPANE GAS SUPPLIER ABOUT INSTALLING A
GAS DETECTING WARNING DEVICE.
IMPORTANT NOTE:
Propane gas conversion kits must be
installed to convert units to propane gas. NOx screens must
be removed before converting to LP. Remove burner as-
sembly and pull NOx screens from each burner tube. When
all the screens are out, reassemble the burner assembly
without the screens.
All propane gas equipment must conform to the safety stan-
dards of the National Board of Fire Underwriters (See NBFU
Manual 58).
For satisfactory operation, propane gas supply pressure
must be within 9.7 - 10.3 inches W.C. at the manifold with all
gas appliances in operation. Maintaining proper gas pres-
sure depends on three main factors:
1. Vaporization rate, which depends on (a) temperature of
the liquid, and (b) wetted surface area of the container or
containers.
2. Proper pressure regulation.
3. Pressure drop in lines between regulators, and between
second stage regulator and the appliance. Pipe size re-
quired will depend on length of pipe run and total load of
all appliances.
t
anks
and
P
iPing
Complete information regarding tank sizing for vaporization,
recommended regulator settings and pipe sizing is available
from most regulator manufacturers and propane gas sup-
pliers.
Since propane gas will quickly dissolve white lead or most
standard commercial compounds, special pipe dope must
be used. Shellac base compounds resistant to the actions
of liquefied petroleum gases such as Gasolac®, Stalactic®,
Clyde’s® or John Crane® are satisfactory.
See the following figure for typical propane gas piping.
200 PSIG
Maximum
5 to 15 PSIG
(20 PSIG Max.)
Continuous
11" W.C.
Second Stage
Regulator
First Stage
Regulator
Typical Propane Gas Piping
r
OOf
t
OP
l
OcatiOn
and
i
nstallatiOn
The gas supply piping location and installation for roof top units
must be in accordance with local codes or, in the absence of
locals codes, with ordinances of the latest edition of the National
