Water Heater Temperature Regulation; Adjustable Control Parameters; Saving Parameters - Lochinvar Shield SNR150-100 Installation & Service Manual

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10
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.
The internal clock does not adjust for
NOTICE
Daylight Savings Time and therefore, will
require a manual adjustment.
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.
52
Installation & Service Manual
TM
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.
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

To save parameters:
Press the ENTER/RESET button.
To keep parameter settings only for a current operating cycle:
Press the MENU/EXIT button 1 time to return to the status
display.
This will

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