53
8. Compare the actual supply gas pressure reading recorded
above to the required minimum/maximum values given
in Table 3 on page 12. Adjust supply gas pressure
as necessary, see Supply Gas Pressure Adjustment on
page 54.
9. When complete turn off gas to the water heater, see
instructions on page 55. Disconnect manometers
and replace all pipe plugs removed for testing. Ensure
all test port needle valves opened during testing are
completely closed.
MANIFOLD GAS
PRESSURE
TEST PORT
SUPPLY GAS
PRESSURE
TEST PORT
GAS VALVE / VENTURI ASSEMBLY TOP VIEW
199,000 & 250,000 Btu/hr MODELS
VENTURI
COMBUSTION
AIR INLET
GAS
VALVE
COMBUSTION
BLOWER
CONNECTION
figure 59
MANIFOLD GAS
PRESSURE
TEST PORT
SUPPLY GAS
PRESSURE
TEST PORT
GAS VALVE TOP DETAIL VIEW
199,000 & 250,000 Btu/hr MODELS
figure 60
GAS VALVE / VENTURI ASSEMBLY SIDE VIEW
199,000 & 250,000 Btu/hr MODELS
VENTURI
LOW GAS
PRESSURE
SWITCH
SUPPLY GAS
CONNECTION
GAS
VALVE
COMBUSTION
AIR INLET
figure 61
lighting the water heater
1. BTH 120 & 150 models: turn the on/off switch on the gas
valve to the "on" position, see Figure 57 and Figure 58.
2. Turn the water heater’s on/off switch to the “on” position.
3. Wait for the control system to complete its boot up sequence.
The Desktop screen showing the current Operating Set
Point and Tank Temperature will be displayed on the control
system’s LCD when the boot up sequence is complete.
4. Using the control system menus and UIm (user interface
module), change the Operating Set Point to a setting higher
than the current tank temperature displayed on the control
system LCD plus the Differential setting to activate a call for
heating. See Control System Operation on page 44.
ON
OFF
MANIFOLD GAS
PRESSURE REGULATOR
COVER SCREW
GAS VALVE TOP VIEW
120,000 & 150,000 Btu/hr MODELS
MANIFOLD GAS
PRESSURE TAP
1/8’ NPT PLUG
SUPPLY GAS
PRESSURE TAP
1/8’ NPT PLUG
INLET
OUTLET
ON/OFF
SWITCH
figure 57
5. record the manifold gas pressure when the 24 Volt Gas Valve
is energized and the main Burner is ignited, the animated gas
valve icon will be displayed on the Desktop screen of the
control system’s LCD when the control system energizes the
24 Volt Gas Valve, a animated flame icon will appear when
main Burner ignition is successful, see the Status Icons
descriptions in Table 11 on page 45.
GAS VALVE SIDE VIEW
120,000 & 150,000 Btu/hr MODELS
MANIFOLD GAS
PRESSURE TAP
1/8’ NPT PLUG
SUPPLY GAS
PRESSURE TAP
1/8’ NPT PLUG
BOTTOM OF TEE
1/8” NPT
TEE FITTING
GAS VALVE
OUTLET
ON/OFF
SWITCH
LOW GAS
PRESSURE
SWITCH
figure 58
6. Compare the actual manifold gas pressure reading recorded
above to the required minimum/maximum values given in Table
3 on page 12. Adjust manifold gas pressure as necessary,
see manifold Gas Pressure Adjustment on page 54.
7. record the supply gas pressure when the 24 Volt Gas Valve is
energized and the main Burner is ignited. This is a “dynamic”
gas pressure reading; while the water heater is firing.
