Thermific®
3.4.3.2 Series 1500, 1700, 2000
| Air Inlet Exhaust |
Round | Vent |
|
Damper
90o Elbow
Installation/Operation
normally closed contacts on the time delay relay and energizes the coil on the relay in the Auxiliary Control Panel. The relay will in turn energize the damper actuator to open the damper. When the damper is in the full open position, the limit switch will close and supply power to the contactor for the blower motor.
Transition
Duct
27" Min.* |
31" * |
24" |
44" Min. * |
Boot Tee/
135 o Tee
To Drain
During this time (about 20 seconds), the air switch will indicate low air flow with the "LowAir" indicator. This indicator will remain on until sufficient air flow is sensed. If the air flow switch is not closed in 120 seconds, the time delay relay will open its normally closed contacts. This will turn off the blower motor and close the inlet damper. The "Low Air" indicator will remain illuminated and the boiler will not operate.
4.2COMBUSTION OPERATING CONDITIONS
The combustion air characteristic of the burner in this boiler is factory set at a condition of utilizing approximately 50% excess air at room temperature (70ºF). Therefore, when taking combustion air from the outdoors in a direct vent system, adjustment of the
*Dimension shown above is based on 12" round ductwork.
A minimum of 44 inches is required behind the boiler to fit the inlet and exhaust connections.
The figure above suggests a duct arrangement using standard duct pieces that will maintain this minimum clearance of 44 inches.
4.0OPERATION
4.1SEQUENCE OF OPERATION
This sequence applies if the optional inlet damper assembly and auxiliary control panel are used. If not the standard Thermific® control sequence applies. (Replaces step #6 of the Sequence of Operation in the Installation and Owner's Manual. "TBIG.")
6.The programmer first energizes Terminal 4 which supplies power to the airflow switch and initiates the adjustable 120 sec. timer on the time delay relay. Terminal 4 also supplies power through the
combustion air damper linkage should not be made until the carbon dioxide or oxygen reading is referred to this condition.
The density of cold outdoor air will be greater than warm air taken from inside the building. Thus, the combustion air blower with outdoor air will deliver a higher air density flow to the burner.
A boiler can be subjected to varying combustion air temperatures. You must put some thought into the air/fuel adjustments to prevent hard start and/or light off rumbling problems. Due to a wide range of operating conditions,
The operational range setting for O2 is 6.0% to 8.0%. Insert your 100º F operating temperature range in the chart below. Start with the Minimum Temperature at the top of the chart; insert temperatures using 5º F increments.
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