Use And Care Manual

whl-590 Rev. 003 Rel. 003 Date 3.22.18
46
C. Additional Precaution for Excess Flow Valve (EFV)
If an excess ow valve (EFV) is in the gas line, check the manufacturer’s
minimum and maximum ow capacity ratings. An improperly sized
EFV will not allow for a full ow of gas to the water heater and will
cause the water heater to malfunction. See Figure 49.
Figure 45 - Excess Flow Valve (EFV)
D. Checking Gas Pressure at the Water Heater for Proper
Operation
NOTE: Refer Figure 50 when checking gas pressure. Loosen the bolts
before checking the gas inlet 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 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 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).
The minimum and maximum inlet gas line pressures must meet the
requirements shown in Table 24.
Natural or LP Gas
Minimum Pressure 3.5” WC
Maximum Pressure 14”WC
Table 23 - Gas Pressure Requirements
Do not re (operate) the water heater until all connections have
been completed and the heat exchanger is lled with water. Doing
so will damage the water heater and void the warranty.
Figure 46 - Gas Valve Detail
E. Setting and Verifying the Combustion Setting
1. After the water heater has red, ip DIP switch seven (7) to the
ON position (low re). Proceed to check heater combustion values.
NOTE: Use a combustion analyzer to ensure CO and CO2 values are
within the range shown in Table 25.
It is required to use a combustion analyzer to verify nal adjustment
according to the combustion chart (Table 25). 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 25, use a T15 Torx screwdriver to adjust the oset
screw in a clockwise (positive) or counterclockwise (negative) direction
(approximately 1/4 turn). See Figure 50. Check your combustion values.
Repeat this procedure until the values obtained on the combustion
analyzer agree with those stated in Table 25.
NOTE: If the heater makes a whistling sound (harmonics) at low re,
adjust the oset screw in a clockwise (positive) direction (approximately
1/8 turn). Check your combustion values and ensure they agree with
those stated in Table 25 before proceeding.
It is very important that the combustion system be set within the
recommended CO measurements listed in Table 25. Visually looking
at the burner does not determine combustion quality. Failure to
measure combustion with a Combustion Analyzer and set the
throttle within the recommended CO measurements could result in
property damage, severe personal injury, or death.
Natural Gas LP Gas
Fan Speed Low High Low High
CO PPM
<175 <175
CO2 (%) 8 - 9 1/2 8 1/2 - 10 9 - 10 1/2 9 1/2 - 11
Table 24 - Combustion Settings
2. When low re settings have been obtained, ip DIP switch seven
(7) to its original (OFF) position. This will return the heater to normal
operation.
3. Flip DIP switch six (6) to ON (high re). Again check combustion
readings with a combustion analyzer.
NOTE: DO NOT adjust the gas valve oset screw at high re. The oset
screw is only used to adjust combustion values at low re.
4. When complete, ip DIP switch six (6) to its original (OFF) position.
This will return the heater to normal operation.
5. Allow heater to operate normally. Ensure it is operating properly.
6. Reinstall the heater front cover.
7. Use a Phillips Head screwdriver to reinstall the heater top cover.