LP-454 Rev. 004 Rel. 002 Date 12.1.17
32
Figure 25 - Gas Valve
1. The gas adapter tting on the water heater is 3/4” NPT.
NOTE: The gas supply pipe size must not be less than 3/4”.
2. The supply line must be sized for the maximum output
of the water heater being installed. If there are additional
gas appliances on the main supply line, size the supply
line for the maximum total COMBINED BTU/Hr draw of the
appliances. This will ensure the supply line is sized to allow
all the appliances to operate at the same time.
3. Measure the length of the gas supply line from the gas
meter to the water heater. The water heater must be
installed downstream of the gas meter to ensure adequate
gas supply.
4. Use the table in this manual or refer to the gas line
manufacturer’s sizing information to determine the correct
supply pipe size. Run the gas supply line in accordance with
all applicable codes.
5. The National Fuel Gas Code (NFPA 54) requires that a
sediment trap (drip leg) be installed in the gas line on
appliances not so equipped. The drip leg must be accessible,
a minimum of 3” in length, and not subject to freezing
conditions. See Figure 25.
6. A manual gas shut-o valve should be installed in the gas
supply line close to the water heater. Locate and install
manual shuto valves in accordance with local and state
requirements.
7. To facilitate any future maintenance, it is also recommended
that an approved gas union tting be installed in the supply
line between the shut-o valve and the 1/2” NPT connection
on the water heater.
8. Use a manometer to test the gas pressure to make sure it
meets the minimum standards and does not exceed the
maximum standards of the water heater.
9. Leak test the gas line pipe before placing the water heater in
operation. Only use approved leak detector liquid solutions
to check for leaks. Never use an open ame to check for
leaks.
C. Gas Valve
Do not do a gas conversion on this appliance without an ocially
approved conversion kit and instructions supplied by HTP. Failure to
use a conversion kit when converting the appliance to re on Natural
or Propane gas will result in extremely dangerous burner operation,
leading to re, explosion, severe personal injury, or death.
Strain on the gas valve and ttings may result in vibration, premature
component failure and gas leakage, and result in re, explosion,
property damage, severe personal injury, or death.
Adjustments to the throttle screw or oset may only be made by
a qualied gas technician using a calibrated combustion analyzer
capable of measuring CO2 and CO. Failure to follow this instruction
could result in re, explosion, property damage, severe personal
injury, or death.
D. Checking Gas Pressure at the Water Heater for Proper
Operation
NOTE: Refer to Figure 25 when checking gas pressure.
1. The water heater and its individual shuto valve must be
disconnected from the gas supply piping system during any pressure
testing of the system at pressures greater than ½ psi (3.5 kPa).
2. The water heater must be isolated from the gas supply piping system
by closing its individual manual shuto valve during any pressure
testing of the gas supply piping system at test pressures equal to or
less than ½ psi (3.5 kPa). Loosen the screw on the pressure tap inlet to
attach a manometer and check the gas inlet pressure.
The minimum and maximum inlet gas line pressures must meet the
requirements shown in Table 11.
Natural or LP Gas
Minimum Pressure 3.5” WC
Maximum Pressure 14”WC
Table 11 - Gas Pressure Requirements
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