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TABLE - Q
Minimum Inlet Water Temperatures
Input | Minimum Return | Minimum |
Btu/hr | Temperature | Setpoint |
|
|
|
1,500,000 | 50°F (10°C) | 105°F (40.6°C) |
___________ | ____________________ | _______________ |
1,700,000 | 50°F (10°C) | 90°F (32.2°C) |
___________ | ____________________ | _______________ |
2,000,000 | 50°F (10°C) | 70°F (23.9°C) |
|
|
|
CAUTION
An appliance allowed to operate at return temperatures below the specified minimum settings may experience problems with the operating controls, safety switches, obstruction of the flue gas passages on the primary heat exchanger, incomplete combustion and possible flue gas spillage. Sustained operation at lower than specified water temperatures may cause hazardous conditions that may result in personal injury or
A boiler installed above radiation level must be provided with a low water cutoff device either as part of the unit or at the time of installation.
WATER FLOW SWITCH
A water flow switch is factory installed in the internal bypass piping on all heating boilers, hot water supply boilers and water heaters. The flow switch is wired in series with the 24 VAC safety control circuit. This wiring connection installs the flow switch in the 24 VAC safety circuit to prove water flow before main burner ignition. A factory supplied flow switch installed in the discharge piping from the top header requires a minimum flow of 26 GPM to make the flow switch and start burner operation. A water flow switch meets most code requirements for a
LOW WATER CUTOFF
(If Equipped)
If this boiler is installed above radiation level, a low water
GAS TRAIN AND CONTROLS
ORIFICE
DIAPHRAGM
VALVE
RATIO VALVE
FIG. 42 Gas Train Assembly
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