11 Operating information
General
How the water heater operates
The Armor 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 Armor 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 Armor 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.
Installation & Operation Manual
Protection features
Outlet temperature, flue temperature, and temperature rise limiting
The outlet temperature is monitored by the water heater outlet temperature sensor. When the outlet temperature exceeds 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 room 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
•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 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.
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