The Solution - How it works...
1.Control panel cover
The control panel cover provides access to the thermostat, ignition module, and transformer.
Installation & Service Manual
16.Sight Glass
The sight glass provides a view of the burner surface, burner flame, and the pilot flame.
2.Burner (not shown)
The burner is a cylindrical stainless steel tube used to regulate burner flame.
3.Drain port
Location from which the heat exchanger can be drained.
4.Flue outlet
The flue outlet allows the connection of the vent pipe to the unit.
17.Temperature and pressure gauge
The temperature and pressure gauge monitors the outlet temperature of the appliance as well as the system water pressure.
18.Temperature sensor
This sensor monitors inlet water temperature. If selected as the controlling sensor, the appliance will maintain the setpoint at this sensor.
5.Gas connection
The gas pipe connection on this appliance is 1/2", or 3/4" NPT. To deliver the correct amount of gas volume to the appliance it may be necessary to have a larger gas line reduced at the appliance. Please reference the National Fuel Gas Code charts for more details.
6.Gas valve
The gas valve allows the proper amount of gas to pass into the burner for combustion.
7.Heat exchanger
The heat exchanger allows system water to flow through specially designed tubes for maximum heat transfer. The glass lined headers and copper finned tubing are encased in a jacket that contains the combustion process.
19.Terminal strip
The boiler is equipped with a terminal strip on the left side of the unit to allow easy connection to contact points.
20.Top panel
Removable panel to gain access to the internal components.
21.Thermostat
The thermostat monitors the water temperature via a temperature sensor and will initiate a call for heat when the water temperature drops below the setpoint plus the differential on the thermostat.
22.Transformer
The transformer reduces 120 VAC supply voltage to 24 VAC for the control circuit.
8.High limit sensor
Device that monitors the outlet water temperature to ensure safe operation. If the temperature exceeds its setting, it will break the control circuit, shutting the appliance down.
9.Ignition module
The ignition module responds to a call for heat signal to provide burner operation.
23.Water inlet (system return)
The water inlet is a 1 1/2" pipe connection that receives water from the system and delivers it to the heat exchanger.
24.Water outlet (system supply)
The water outlet is a 1 1/2" pipe connection that supplies water to the system with connections for a flow switch, a relief valve, and a temperature and pressure gauge.
10.Junction box
The junction box contains the connection points for the line voltage power and all pumps.
11.Performance loop
A pumped bypass provides constant flow through the heat exchanger when the building system flow is reduced.
12.Performance Loop Pump
The pump ensures adequate flow to operate the unit.
13.Pilot (not shown)
The pilot is a spark ignition device used to light a pilot flame which in turn is used to light the main burners.
14.Pump relay
The pump relay energizes the pump on a call for heat.
15.Relief valve
The relief valve is a safety device that ensures the maximum pressure of the appliance is not exceeded.
25.Gas manifold pipe
Delivers gas from the gas valve to the main burners through a number of orifices.
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