Lochinvar SNR150-100 Water heater temperature regulation, Adjustable control parameters

TM

Installation & Service Manual

11 Operating information

Water heater temperature regulation

Operating temperature (target)

The electronic control module senses water temperature in the tank and regulates water heater ignition and firing rate to achieve a target temperature. The target temperature can be set between 60°F and 185°F.

High limit operations

When the heat exchanger outlet temperature exceeds 203°F, high limit action occurs. The burner shuts down until the heat exchanger outlet water cools down, and requires manual reset of the control before operation will resume. To reset control, push the RESET key on the display.

Low water cutoff protection

1.The electronic control module uses sensing of both heat exchanger supply and return temperatures. If the flow rate is too low or either temperature too high, the control module modulates and shuts the burner down. This ensures water heater shutdown in the event of low water or low flow conditions in the heat exchanger.

Adjustable control parameters

To access the control parameters, press the MENU button on the display. When finished, press the MENU button again to return to the status display. Use the NEXT and PREVIOUS buttons to select the parameter you wish to change.

Date and time

The control uses an internal clock for the night setback feature and for logging of events. For these features to work correctly, the clock must be set when the water heater is first installed or anytime the water heater has been powered off for more than 30 days. The date and time are displayed as “MM:DD:YY W hh:mm”. MM = month, DD = date, YY = year, W = day (1 = Monday, 2 = Tuesday, etc.), hh = hour (24 hour time; 2:00 PM = 14:00), mm = minutes.

Tank Differential

Once the tank set point is satisfied, the tank temperature must drop below the set point by this amount before the heater will fire again. The temperature range of this parameter is 3.6°F to 18°F. The default value is 6.3°F.

Temperature units (°F/°C)

The control can be configured to display temperature in either °C or °F. This setting can be changed by the user or the installer. The default is °F.

Night setback temperature

Once the internal clock has been set correctly, the night setback feature can be used to program a lower tank set point. The temperature range for this parameter is 32°F to 140°F. The feature is turned off with a setting of 32°F. The default value is 32°F.

Night setback times

If the night setback temperature is set to anything other than 32°F, the night setback feature becomes active. This will require start and stop times to be programmed for the days that reduced temperatures are required. Each day of the week (Sunday through Saturday) will have an ON and OFF time.

Night setback can be programmed to skip certain days of the week, and to remain active throughout certain days of the week. To skip a day, set the ON and OFF times for that day to any time before 12:00 (noon), and equal to each other. Night setback will become inactive at the OFF time on the previous day, and remain inactive until the ON time on the following day. To have night setback remain active throughout an entire day, set the ON and OFF times to any time after 12:00 (noon), and equal to each other. Night setback will become active at the ON time on the previous day, and remain active until the OFF time on the following day.

Saving parameters

NOTICE

The internal clock does not adjust for Daylight Savings Time and therefore, will require a manual adjustment.

To save parameters:

Press the ENTER/RESET button.

Tank set point

When a HW call for heat becomes active, the control will use the tank set point to determine the firing rate of the water heater based on the actual water temperature. The temperature range of this parameter is 60°F to 185°F. The default value is 125°F.

To keep parameter settings only for a current operating cycle:

Press the MENU/EXIT button 1 time to return to the status display.

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