lp-673 Rev. 000 Rel. 001 Date 8.30.18
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3. LP (Liquid Propane) Gas Pipe Sizing
Contact gas supplier to size pipes, tanks, and 100% lockup gas
pressure regulator. Adjust propane supply regulator provided
by the gas supplier for 14 inches w.c. maximum pressure.
B. Gas Connection Requirements
1. The gas connection fitting on the water heater is ¾” NPT.
NOTE:
The pipe size must not be less than ¾”.
2. The supply line must be sized for the maximum output of
the water heater being installed. If there are additional gas
appliances from the main supply line, measure the size of
the supply line according to the COMBINED total maximum
BTUH draw for the appliances as if they were operating at
the same time.
3. Measure the length of the gas supply line from the gas
UNION
SEDIMENT TRAP
MANUAL SHUT OFF
BALL VALVE
Figure 33 - Gas Line with Shut-Off and Sediment Trap Detail
meter to the water heater. Water heater must be installed
downstream of the gas meter to ensure adequate gas
supply. Use the tables in this manual or refer to the gas line
manufacturer’s sizing information to determine the correct
supply pipe size.
4. 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 40.
5. A manual gas shut-off valve should be installed in the gas
supply line close to the water heater. See Figure 40 for detail.
6. To facilitate any future maintenance, it is also recommended
that an approved gas union fitting be installed in the supply
line between the shut-off valve and the ¾” NPT connection
on the water heater.
7. 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.
8. Leak test the gas line pipe before placing the water heater in
operation. Only use approved leak detector liquid solutions
to check for leaks.
9. Do not operate the water heater until all connections have
been completed and the heat exchanger is filled with water.
C. Additional Precaution for Excess Flow Valve (EFV)
If an excess flow valve (EFV) is in the gas line, check the manufacturer’s
minimum and maximum flow capacity ratings. An improperly sized
EFV will not allow for a full flow of gas to the water heater and will
cause the water heater to malfunction. See Figure 41.
Figure 34 - Excess Flow Valve (EFV)
D. Checking Gas Pressure at the Water Heater for Proper
Operation
NOTE:
Refer to Figure 42 when checking gas pressure. Loosen the
bolts before checking the gas inlet pressure.
1. The water heater and its individual shutoff valve must be
disconnected from the gas supply piping system during any pressure
testing of the system at test 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 shutoff valve during any pressure
testing of the gas supply piping system at test pressures equal to or
less than ½ psi (3.5 kPa).
The minimum and maximum inlet gas line pressures must meet the
requirements shown in Table 19.
Natural or LP Gas
Minimum Pressure
3.5” WC
Maximum Pressure
14”WC
Table 23 - Gas Pressure Requirements
Do not fire (operate) the water heater until all connections have
been completed and the heat exchanger is filled with water. Doing
so will damage the water heater and void the warranty.
Figure 35 - Gas Valve Detail
E. Setting and Verifying the Combustion Setting
1. After the water heater has fired, flip DIP switch seven (7) to the ON
position (low fire). Proceed to check heater combustion values.
NOTE:
Use a combustion analyzer to ensure CO and CO2 values are
within the range shown in Table 20.
It is required to use a combustion analyzer to verify final adjustment
according to the combustion chart (Table 20). Failure to do so could
result in serious personal injury or death.
If the readings obtained are lower or higher than the combustion
readings in Table 20, use a T15 Torx screwdriver to adjust the offset
screw in a clockwise (positive) or counterclockwise (negative) direction
(approximately 1/4 turn). See Figure 42. Check your combustion values.
Repeat this procedure until the values obtained on the combustion
analyzer agree with those stated in Table 20.
NOTE:
If the heater makes a whistling sound (harmonics) at low fire,
adjust the offset screw in a clockwise (positive) direction (approximately
1/8 turn). Check your combustion values and ensure they agree with
those stated in Table 20 before proceeding.