Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS service manual OPERATION Continued

Commercial Pool Heaters

OPERATION Continued

Figure 44 – Vertical Pool Heater Piping

Figure 45 – Horizontal Pool Heater Piping

OPERATING TEMPERATURE CONTROL

The pool heater is equipped with a microprocessor based adjustable digital temperature control to provide ON/OFF operation. The temperature control is located behind the overlay on the front of the control panel. Operation is based on temperature inputs from immersion sensors, and, if desired, an external thermostat. The temperature control will turn on and off based upon the temperature measured by the pool return sensor. This sensor is factory installed in a bulbwell located in the inlet piping to the pool heater, upstream of the 3-way automatic bypass valve. The temperature control will turn on and off based upon an external thermostat connected between terminals R1 and W1 on the terminal board. The temperature control will also turn off if the temperature measured by the pool heater output sensor exceeds a limit (default = 200°F) or if the temperature measured by the optional pool supply sensor exceeds another limit (default = 100°F). In addition, the temperature control will operate a factory installed 3-way automatic bypass valve. This is done to maintain a minimum temperature at the inlet to the pool heater (default = 130°F), automatically protecting the pool

heater from condensation of the flue products. If the boiler inlet temperature is not satisfied within 15 minutes the controller will shut the unit down. To reset the unit, press any key. No manual valve adjustments are required.

An LCD is provided to display various readings and operating parameters. Three (3) pushbuttons are available to change the display and to program parameters (Figure 46).

Figure 46 - Temperature Control Display and Programming Keys

Specifications

•Set Point Adjustment Range:

OFF, 55°F up to 105°F (13°C up to 41°C).

•Differential Adjustment Range: 1°F up to 20°F (1°C-11°C)

•Temperature Accuracy: +/- 1°F.

•Display Resolution: 1°F via Liquid Crystal Display (LCD).

•Sensor: NTC Thermistor, 10k ohms @ 77°F (25°C).

•Operating Humidity: < 90% RH Non-condensing.

•Operating Ambient Temperature: -20° to 140°F (-30° to 60°C).

The programming keys are as follows:

Select - Allows the user to select the reading or parameter being displayed. Each time the key is pressed, a different indicator will appear which describes the value being shown. These are detailed as follows:

Up and Down Arrows - While in the Adjust mode, the user can increase or decrease the parameter being shown.

The default display mode is the View mode, indicated in the upper right-hand corner of the display.

The default value shown is the Pool Temperature, indicated by the arrow pointing to the POOL text on the overlay. If the

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