Mighty Max Hydronic Boiler
Page 19
Use a single, inclined manometer or digital
manometer with a 4.0 inch water column range. Install
shutoff valves at the gas orifice (regulator outlet) tap
(red), at the venturi inlet tap (blue) and at the venturi
throat tap (yellow). After installing the shutoff valves,
be certain they are closed.
1.
With the heater off, connect the positive side of
the manometer to the shutoff valve on the
venturi inlet tap (blue). Open the shutoff valve.
2.
Loosen the nut on the blower damper to allow
for adjustment. Turn the boiler on so that the
blower is running and the boiler is not firing. In
this unfired condition, adjust the damper until
the venturi inlet pressure (blue tap) is 1.2 inches
water column.
3.
Approximately 40 seconds after the blower starts
the gas valves will open. The boiler is now
firing. If the heater is not running, check all
manual gas valves and heater safety devices.
Ensure proper gas supply pressures according to
the table in Section 2.
4.
Now that the boiler is firing, use the blower
damper to readjust the venturi inlet pressure
according to the installation’s altitude in Table
10 (+1.6" w.c. at sea level).
Elevation
Venturi Inlet
Gas
Throat
Ft.
Pressure
Pressure
Differential
(Blue Tap)
Offset
Pressure
“WC H
2
0”
“WC H
2
0”
“WC H
2
0”
SEA LEVEL
+1.6
+0.4
+2.6
1000
+1.5
+0.4
+2.5
2000
+1.5
+0.4
+2.4
3000
+1.4
+0.4
+2.3
4000
+1.4
+0.3
+2.2
5000
+1.3
+0.3
+2.2
6000
+1.3
+0.3
+2.1
7000
+1.2
+0.3
+2.0
8000
+1.2
+0.3
+1.9
9000
+1.1
+0.3
+1.9
10000
+1.1
+0.3
+1.8
Table 10. Venturi Pressure Settings.
5.
Leaving the positive side of the manometer
connected to the venturi inlet tap (blue), connect
the negative side of the manometer to the shutoff
valve on the gas orifice tap (red). Open the
shutoff valve to take a pressure reading. This
reading is called the gas pressure offset. Using
the regulator only, adjust the gas pressure offset
according to the installation's altitude in Table 5
(+0.4" w.c. at sea level). REPLACE THE
REGULATOR CAP BEFORE TAKING GAS
PRESSURE READINGS. Turn the regulator
screw clockwise to decrease the gas pressure
offset, turn the regulator screw counter-
clockwise to increase the offset.
6.
Using the toggle switch, turn the heater off. Turn
the heater back on and check the gas pressure
offset after the heater has fired. If the gas offset
pressure is not according to Table 10, adjust the
regulator as needed.
7.
While the heater is still running, close the
shutoff valve on the gas orifice tap (red), then
remove the manometer hose from the shutoff
valve. Connect the negative side of the
manometer to the shutoff valve on the venturi
throat tap (yellow). This reading is called the
venturi throat differential pressure and should
appear according to altitude in Table 10 (+2.6"
w.c. at sea level). If it does not appear according
to Table 10, contact a qualified service
technician.
“Low” Side of
Manometer
“High” Side of
Manometer
Venturi Inlet
Tap (Blue)
Venturi Throat
Tap (Yellow)
Gas Orifice
Tap (Red)
Figure 15. Measurement of Venturi Throat Pressure
Differential.
After setting all pressures, turn the heater off and
replace each shutoff valve with the factory installed
threaded plugs. The venturi has now been adjusted for
proper operation.
3D. To Start Up System
(See Section 3A for Startup Requirements)
1.
Be certain the system pump is running.
2.
Set the thermostat or aquastat to its lowest
setting.
3.
Turn off electric power to the appliance.
4.
Remove the control access panel.
5.
Turn off the manual gas valve.
6.
Wait five (5) minutes to clear out any gas, then
smell for gas, including near the floor. Be sure to
smell next to the floor because some gas is
heavier than air and will settle on the floor.
