Lochinvar 1, 000 Installation With A Chilled Water System, Boiler Operating Temperature Control

Boiler Operation

28.Turn the run/stop switch to the “RUN” position to start boiler operation.

29.Push the resets for low water level, high water temperature and flame failure.

30.Observe the boiler synchronization process before start-up of the boiler begins.

31.Boiler should begin the start-up process for the sequence of operation.

32.The boiler will fire at 50% of rated input on initial start-up and adjust input as required to meet system demand.

33.	The integral bypass valve will automatically	adjust
	to maintain minimum inlet temperatures	to the
	primary heat exchanger.

34.Ensure that inlet water temperature does not fall below the specified minimum for the boiler.

35.	Based on system demand, the	boiler may	run	for
	an extended period of time at	a reduced	rate	of
	input to maximize efficiency.

36.As system demand is satisfied, the burner will cycle off and the combustion air blower will run for a post purge operation before the boiler shuts down.

INSTALLATION WITH A

CHILLED WATER SYSTEM

EXPANSION
TANK
	HEATING AND
	COOLING COIL
GAS SUPPLY	PUMP
	WATER
	SUPPLY
	CHILLER

FIG. 82 Installation with a Chilled Water System

Pipe refrigeration systems in parallel. Install duct coil downstream at the cooling coil. Where the hot water heating boiler is connected to a heating coil located in the air handling units which may be exposed to refrigeration air circulation, the boiler piping system must be equipped with flow control valves or other automatic means to prevent gravity circulation of the boiler water during the cooling cycle. The coil must be vented at the high point and hot water from the boiler must enter the coil at this point. Due to the fast heating capacity of the boiler, it is not necessary to provide a ductstat to delay circulator operation. Also, omit thermostat flow checks as the boiler is cold when heating thermostat is satisfied. This provides greater economy over maintaining standby heat.

BOILER OPERATING

TEMPERATURE CONTROL

The operating temperature control for the boiler is the Excel 10 controller. It is located on the back side of the front control panel, behind the front access door. Access to adjust the temperature set point and other owner/operator adjustable points is made through the Command Display located on the front control panel. The sensing element for the operator is placed in a bulb well installed in the inlet connection to the boiler. The outlet sensor is located in a bulb well on the outlet side of the primary heat exchanger top header. Carefully observe the discharge water temperature on the initial boiler on cycles. The location of the temperature sensor may generally require a lower temperature set point on the operating control to achieve the desired discharge water temperature from the boiler. The return/inlet sensing element location allows a boiler to sustain longer burner on cycles.

The location of the operating sensor, inlet or outlet, is selectable from the screen on the Command Display.

The exact temperature set point is based on your system’s requirements. Set the control set point(s) to the desired operating water temperature. Observe the boiler discharge temperature after each set point adjustment to ensure proper operation.

The maximum set point for operation of a heating boiler is 220°F (104.4°C) on a standard Excel 10 control. The minimum temperature setting programmed into this standard Excel 10 control is 100°F (37.7°C).

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