Lochinvar 1, 000 through 2 warranty Sequence of Operation, Heat Transfer Process

SEQUENCE OF OPERATION

1.The power switch is placed in the “ON” position and the run/stop switch is in the “RUN” position.

2.120 VAC Power is supplied to the control junction box and to the integral pump.

3.120 VAC Power is supplied to the control Transformer, Ignition Module and Excel 10.

4.The bypass valve will synchronize on initial startup only.

5.24 VAC is supplied to all low voltage controls.

6.Integral pump starts and is proven by a Flow Switch.

7.Command Display Set Point (Operating Temperature) is set to call for heat.

8.	Excel 10 Controller initiates	a start-up sequence
	by checking the Temperature	Sensors and input
	signals from the safety controls.

9.Excel 10 enables the Ignition Module.

10.Ignition Module enables the Variable Frequency Drive.

11.Excel 10 Controller drives the Variable Frequency Drive.

12.The Variable Frequency Drive supplies the

Combustion Air Blower with 230 VAC 3 phase power.

18.Relay contacts prove operation of the Igniter, Gas Valves and Safety Switches to the Excel 10.

19.Variable Ratio Gas Valve senses the pressure from

the Combustion Air Blower and supplies gas to the orifice and into the Blower inlet to pre-mix.

20.The Gas/Air mixture is forced into the Burner and out of the Burner Ports under pressure.

21.Hot Surface Igniter lights the Gas/Air mixture and then serves as a flame sensor to prove Main Burner Flame by rectification.

22.Burner is now in a soft start firing at 50% of rated input.

23.Excel 10 Controller signals the Variable Frequency Drive to adjust blower speed based on desired water temperature Set Point.

24.	Burner input rate is variable		down to 25% of rate
	or	up to 100% of rate as	required to satisfy the
	Set	Point programmed into	the Command Display.

25.Excel 10 Controller senses Inlet Water Temperature to the

Primary Heat Exchanger	and provides a	signal
to adjust the floating	point Bypass	Valve
(based on return/inlet control choice).

26.Bypass Valve adjusts position to maintain an inlet temperature to the Primary Heat Exchanger above the dew point of flue products.

27.Operation of the Bypass Valve maintains water

temperatures	above the dew	point of	flue products
to ensure	that condensate	formation	occurs only
in the Secondary Heat Exchanger.

13.Combustion Air Blower starts operation and drives to 100% speed for prepurge.

14.Blower makes the low air switch contacts to enable the Ignition Module.

15.Blower cycles down to 50% speed and the Ignition Module initiates the heat-up sequence of the Hot Surface Igniter.

16.Hot Surface Igniter proves 1800°F (982°C) Ignition Temperature by current draw through the Ignition Module.

17.The Ignition Module supplies voltage to the Variable Ratio Gas Valve and the Redundant Gas Valve.

Heat Transfer Process

28.Burner Input continues to increase until water temperature reaches the Set Point temperature.

29.Burner Input may stabilize at a fixed rate where demand equals input.

30.Burner Input will decrease rate when water temperature exceeds temperature Set Point and demand.

31.Heated products of combustion pass over the Primary Heat Exchanger transferring heat to the water.

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