Lochinvar 999 - 750, 399 Ignition Systems and Stages, Operating Modes, Programming Buttons

Installation and Service Manual

STG MODE

Used to distinguish between single and dual ignition module appliances. Applies ONLY on 650,000, 750,000, and 990,000 Btu/hr models.

OUTDR DSGN

Design outdoor air temperature used in the heat loss calculations.

BOIL START

Starting temperature of the boiler heating curve at outdoor starting temperature.

BOIL DSGN

Design heating supply water temperature.

WWSD

Set temperature for warm weather shut down.

BOIL MIN

Set minimum boiler target supply temperature.

BOIL MASS

Set boiler’s thermal mass. The lower the value, the shorter the interstage delay.

BOIL DIFF

Set boiler differential during outdoor reset operation.

Set Point TARGET

Set point target whenever a reset override is present.

Ignition Systems and Stages

The 399,999 - 500,000 Btu/hr models have one ignition system and 2 stages of operation. The 650,000 - 750,000 Btu/hr models have one ignition system and 3 stages of operation. On the 990,000 Btu/hr model, there are two ignition systems and 3 stages of operation.

Note: For Stage Mode Delay on the 650,000 - 750,000 Btu/hr models set Stage Mode to 1. On the 990,000 Btu/hr model, set Stage Mode to 2.

The 1,260,000 - 2,070,000 Btu/hr models have two ignition systems and 4 stages of operation

On models with two ignition systems, ignition system 1 controls stages 1 and 2 and ignition system 2 controls stages 3 and 4. Stage 2 is tied to stage 1 and stage 4 is tied to stage 3. You can program the control to operate each ignition system independently. You can also program the ignition stage sequence as 1, 2, 3, and 4, or 3, 4, 1, and 2. This allows greater programming flexibility to meet your individual needs.

Note: One ignition system controls 1 - 3 stages on the 399,999 - 750,000 Btu/hr models.

Operating Modes

There are three operating modes on the temperature control: Mode 1 - Boiler Operation

Mode 2 - Water Heater Operation

Mode 3 - Sequenced Operation

You can program the different values within each mode to control the operation, stages, differentials, water temperature, and pump operation.

Programming Buttons

Program and navigate the temperature control using the three programming buttons located under the LCD screen. The buttons are labeled “SELECT”, “+”, and “–” (see FIG. 46).

FIG. 46 Programming Buttons

View Menu

This is the default screen that appears after start up. The word “View” appears in the upper right part of the screen (FIG. 47). The View Menu provides current operational information.

To view the operational information, press the “Select” button to scroll through the different areas. TABLE–R, page 44 shows the various View Menu information areas.

To view the various settings without reprogramming the controller, press and hold the “Select” button for at least three seconds. The controller will display in one-second intervals each setting currently programmed into the controller.

FIG. 47 View Menu

Adjust Menu

The Adjust Menu allows you to change settings or modes. The word “Adjust” appears in the upper right part of the screen. The unit will shut down while in the Adjust mode.

To activate the Adjust Menu, press in and hold all three programming buttons for three seconds. The LCD screen will change from the “View” menu to the “Adjust” menu. The operating mode will appear as either the number 1, 2, or 3, just under the word “Adjust” (see FIG. 48).

FIG. 48 Adjust Menu

45