Instructions / Assembly

28
WHL-590 REV. 7.27.16
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 18.
D. ADJUSTING GAS PRESSURE AT THE WATER HEATER
NOTE: Refer Figure 19 when adjusting 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 17.
LP GAS
NATURAL GAS
Minimum Pressure
3.5” WC
Minimum Pressure
3.5” WC
Maximum Pressure
14” WC
Maximum Pressure
14” WC
Table 17 – Gas Pressure Requirements
NOTICE
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.
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 CO
2
values are within the range shown in Table 18.
It is required to use a combustion analyzer to verify final adjustment according to the combustion chart (Table 18). 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 18, use a 4mm Allen key to adjust the offset screw in
a clockwise (positive) or counterclockwise (negative) direction (approximately 1/4 turn). See Figure 20. Check your combustion values.
Repeat this procedure until the values obtained on the combustion analyzer agree with those stated in Table 18.
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 18 before proceeding.
It is very important that the combustion system be set within the recommended CO measurements listed in Table 18. 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.
COMBUSTION SETTINGS
Figure 20 – Gas Valve Offset Screw
NATURAL GAS
LP GAS
FAN SPEED
LOW
HIGH
LOW
HIGH
CO PPM
<175
<175
<175
<175
CO
2
(%)
8 – 9 ½
8 ½ - 10
9 – 10 ½
9 ½ - 11
Table 18 – Combustion Settings
Figure 19 – Inlet Gas Pressure Port
Detail
Figure 18 – Excess Flow Valve (EFV)