Install Instructions
16
GAS CONNECTIONS
WARNING
THE INLET GAS PRESSURE MUST NOT EXCEED THE VALUE
SPECIFIED BY THE MANUFACTURER ON THE RATING
PLATE (10.5” W.C. - NATURAL GAS, 13.0” W.C. - PROPANE
GAS). EXPOSURE TO HIGHER GAS SUPPLY PRESSURE
MAY CAUSE DAMAGE TO THE GAS VALVE WHICH COULD
RESULT IN FIRE OR EXPLOSION. IF OVERPRESSURE HAS
OCCURRED SUCH AS THROUGH IMPROPER TESTING
OF GAS LINES OR EMERGENCY MALFUNCTION OF THE
SUPPLY SYSTEM, THE GAS VALVE MUST BE CHECKED
FOR SAFE OPERATION. MAKE SURE THAT THE OUTSIDE
VENTS ON THE SUPPLY REGULATORS AND THE SAFETY
VENT VALVES ARE PROTECTED AGAINST BLOCKAGE.
THESE ARE PARTS OF THE GAS SUPPLY SYSTEM, NOT
THE HEATER. VENT BLOCKAGE MAY OCCUR DURING ICE
STORMS.
IT IS IMPORTANT TO GUARD AGAINST GAS VALVE
FOULING FROM CONTAMINANTS IN THE GAS WAYS. SUCH
FOULING MAY CAUSE IMPROPER OPERATION, FIRE OR
EXPLOSION.
IF COPPER SUPPLY LINES ARE USED THEY MUST
BE INTERNALLY TINNED AND CERTIFIED FOR GAS
SERVICE.
BEFORE ATTACHING THE GAS LINE BE SURE THAT ALL GAS
PIPE IS CLEAN ON THE INSIDE.
TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS
SUPPLY LINE, A SEDIMENT TRAP MUST BE INCORPORATED
IN THE PIPING. SEE PIPING DIAGRAMS. THE SEDIMENT
TRAP MUST BE READILY ACCESSIBLE AND NOT SUBJECT
TO FREEZING CONDITIONS. INSTALL IN ACCORDANCE WITH
THE CURRENT EDITION OF ANSI Z223.1 OF THE NATIONAL
FUEL GAS CODE.
To prevent damage, care must be taken not to apply too
much torque when attaching gas supply pipe to gas valve
gas inlet.
Fittings and unions in the gas line must be metal to metal type.
Apply joint compounds (pipe dope) sparingly and only to the
male threads of pipe joints. Do not apply compound to the rst
two threads. Use compounds resistant to the action of liqueed
petroleum gases.
BEFORE PLACING THE HEATER IN OPERATION, CHECK
FOR GAS LEAKAGE. Use soap and water solution or other
material acceptable for the purpose in locating gas leaks.
DO NOT USE MATCHES, CANDLES, FLAME OR OTHER
SOURCES OF IGNITION FOR THIS PURPOSE.
DISCONNECT THE HEATER AND ITS MANUAL GAS
SHUTOFF VALVE FROM THE GAS SUPPLY PIPING SYSTEM
DURING ANY PRESSURE TESTING OF THAT SYSTEM AT
TEST PRESSURES IN EXCESS OF 1/2 PSIG. THE GAS
SUPPLY LINE MUST BE CAPPED WHEN NOT CONNECTED
TO HEATER.
THE HEATER MUST BE ISOLATED FROM THE GAS SUPPLY
PIPING SYSTEM BY CLOSING ITS MANUAL GAS SHUTOFF
VALVE DURING ANY PRESSURE TESTING OF THE GAS
SUPPLY PIPING SYSTEM AT TEST PRESSURES EQUAL TO
OR LESS THAN 1/2 PSIG (3.44kPa).
CORRECT GAS
MAKE SURE the gas on which the heater will operate is the
same as that specied on the heater model and rating plate. Do
not install the heater if equipped for a different type gas - contact
the heater supplier.
SIZING GAS SUPPLY LINE
The iron pipe or equivalent pipe sizes in Table 6 are
derived from Table C-3 in the NATIONAL FUEL GAS CODE.
The pipe sizes are based on a supply line gas pressure
drop of 0.3 inches of water column from the gas meter to
the point of installation of the heater(s). For natural gas,
a heating value of 1050 Btu/ft
3
and a specific gravity of
0.60 has been assumed. A heating value of 2500 Btu/ft
3
and a specific gravity of 1.53 has been assumed for L.P.
(propane) gas.
Where it is necessary to use an excess number of pipe ttings, i.e.,
elbows, tees and valves, in the gas supply line, use pipe at least
one size larger than that recommended in Table 6 to compensate
for the increased pressure drop.
If the service pressure is 4.5 inches W.C. (1.12kPa) for natural
gas or (11 inches (1.74kPa) for L.P. gas) of water column or
less, use pipe size larger than specified in Table 6 to minimize
pressure drop in the line.
GAS METER SIZE - City Gases Only
Be sure that the gas meter has sufcient capacity to supply the
full rated gas input of the heater as well as the requirements of
all other gas red equipment supplied by the meter. If gas meter
is too small, ask the gas company to install a larger meter having
adequate capacity.
TABLE 6
GAS SUPPLY PIPE SIZES (IN INCHES)
NATURAL GAS (1050 Btu/ft
3
) PROPANE GAS (2500 Btu/ft
3
)
Distance To Heater
From Meter (FT./M) HW-120M HW-160M HW-200M HW-225M HW-120M HW-160M HW-200M
10 (3M) 1/2 3/4 3/4 3/4 1/2 1/2 1/2
30 (9.1M) 3/4 3/4 1 1 1/2 3/4 3/4
50 (15.2M) 3/4 1 1 1 3/4 3/4 1
80 (24.4M) 1 1 1 1/4 1 1/4 3/4 1 1
100 (30.5M) 1 1 1/4 1 1/4 1 1/4 3/4 1 1
150 (45.7M) 1 1 1/4 1 1/4 1 1/4 1 1 1 1/4
200 (61M) 1 1/4 1 1/4 1 1/4 1 1/2 1 1 1/4 1 1/4