Operating Information; Operating Information General; Protection Features; How The Water Heater Operates - Lochinvar 151 - 801 Operation Manual

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Operating information

General

How the water heater operates

The outdoor water heater uses an advanced stainless steel heat
exchanger and electronic control module that allows fully
condensing operation. The blower pulls in air and pushes flue
products out of the water heater through the heat exchanger
and flue piping. The control module regulates blower speed
to control the water heater firing rate. The gas valve senses the
amount of air flowing into the water heater and allows only the
right amount of gas to flow.
Control inputs and outputs
Tank thermostat / tank sensor
Either of these inputs will tell the water heater to provide heat
to the water tank. If a tank sensor is connected, the SMART
SYSTEM control will ignore the tank thermostat.
0 - 10VDC input (set point or power)
The outdoor water heater can be controlled by a Building
Management System (BMS) using a 0 - 10 VDC signal. The
control can be configured by the installer to use this signal to
either control set point or firing rate. This signal can be sent to
the heater through ModBus as well.

Temperature control

Modulation
The outdoor water heater is capable of modulating its firing
rate from a minimum of 20% to a maximum of 100%. The
firing rate is dictated by the hot water draw and various other
temperature limitations.
Night setback
The controller may be programmed to reduce the DHW set
point during certain times each week. Seven different start and
stop times may be programmed for the DHW setback.
Flame current support
To prevent nuisance shutdowns when the water heater is firing
at minimum rates, the control will increase fan speed when the
flame signal drops too low.
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Outdoor Armor Water Heater

Protection features

Outlet temperature, flue temperature, and temperature
rise limiting
The outlet temperature is monitored by the water heater outlet
temperature sensor.
185°F, the unit will reduce the fan speed. If the outlet water
temperature exceeds 195°F the control will shut the unit down
until it cools off.
The control module monitors the flue temperature by a sensor
located in the flue exhaust. If the flue temperature exceeds
215°F the control will reduce the maximum fan speed. If
the flue temperature exceeds 240°F the control will shut the
unit down. The unit will restart automatically once the flue
temperature drops 25°F and the minimum off time has expired.
The control monitors the temperature difference between
the inlet and the outlet sensor. On Models 151 - 501 if this
difference is between 25 - 30°F the control will reduce the fan
speed. If the temperature difference exceeds 30°F the control
will shut the unit down.
On Models 601 - 801 if the temperature difference is between
30 - 35°F the control will reduce the maximum fan speed. If
the temperature difference exceeds 35°F the control will shut
the unit down.
The unit will restart automatically once the temperature
difference has dropped below 25°F (Models 151 - 501) or 30°F
(Models 601 - 801) and the minimum off time has expired.
Freeze protection
DO NOT install the water heater in a location likely to freeze.
The following integral feature of the SMART SYSTEM control
module provides some protection for the water heater.
• The SMART SYSTEM control module provides
freeze-up protection as follows when the water heater
water temperature drops below 45°F:
• Below 45°F, the water heater pump operates constantly.
• Below 37°F, the water heater turns on.
• The water heater and pump will turn off if water
heater water temperature rises above 45°F.
CAUTION
Installation & Operation Manual
When the outlet temperature exceeds
This feature of the SMART SYSTEM control
module does not eliminate the possibility
of freezing. The installation must still
use recognized design, installation and
maintenance practice to prevent freeze
potential for the water heater.