Lochinvar 999 - 750 Installation with a Chilled Water System, Installation and Service Manual

Installation and Service Manual

9.Inspect the liquid level in the expansion tank. The system must be full and under normal operating pressure to ensure proper water level in the expansion tank. Ensure that diaphragm type expansion tanks are properly charged and not water logged.

10.Start the boiler according to the operating instructions in this manual. Operate the system, including the pump, boiler and radiation units, for one hour.

11.Recheck the water level in the expansion tank. If it exceeds half the tank volume, open the tank to reduce the water level. Recheck pressure charge on diaphragm type tanks.

12.Shut down the entire system and vent all radiation units and high points in the system.

13.Close the water makeup valve and check the strainer and pressure reducing valve for sediment or debris. Reopen the water makeup valve.

14.Verify system pressure with the boiler pressure gauge before beginning regular operation.

15.Within three days of startup, recheck and bleed all air vents and the expansion tank using these instructions.

Installation with a Chilled Water System

Pipe refrigeration systems in parallel. Install duct coil downstream at 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 (see FIG. 41).

FIG. 41 Installation with a Chilled Water System

Boiler Operating Temperature Control

This unit can have up to four sensors. The four sensors are for inlet temperature, outlet temperature, system/tank temperature, or outdoor air temperature.

If the unit is ordered as a boiler without any options and you need remote sensing, you can relocate either the inlet or outlet sensors. For best performance, do not relocate the inlet or outlet sensors. Install an optional system sensor.

If the unit is ordered as a water heater, the tank sensor is included with the unit. Do not relocate the inlet or outlet sensors from their bulbwells.

The digital electronic operating temperature control for these units is located on the front control panel. The sensing elements for the temperature control are placed in the inlet and outlet bulbwells. See Remote Mounting of Sensors (Outdoor Air Sensor), on page 48 of this manual. Carefully observe the discharge water temperature on the initial boiler “ON” cycles. The location of the temperature sensor will generally require a lower temperature set point on the operating control to achieve the desired discharge water temperature from the boiler. These sensing element locations allow a boiler operating with a low to moderate flow rate to sustain longer burner on cycles, preventing short boiler “ON” cycles based on high discharge water temperatures. For example, a boiler operating with a 180°F (82°C) discharge and a 20°F (11°C) temperature rise would require approximately a 160°F (71°C) to 165°F (74°C) set point with the temperature sensor installed on the inlet side of the heat exchanger. The exact temperature set point is based on your system’s requirements.

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