Lochinvar 402 - 2072 operation manual Operating information, General, How the appliance operates

Installation & Operation Manual

7 Operating information (continued)

General

How the appliance operates

The Copper-fin II uses a copper finned tube heat exchanger to transfer heat from the flue products to the water. An electronic control module monitors various inputs to initiate a call for heat. The blower provides both primary and secondary air to the burner and forces the flue products out of the combustion chamber and into the vent system. The control module regulates the blower speed and firing stages, based upon the heat demand. Gas valves regulate the amount of gas supplied for the firing stages, which is then mixed with the combustion air supplied to the burner.

NOTICE	If an inline high gas pressure regulator is
	used, it MUST BE of the lockup type and
	be located a minimum of 10 feet from
	the appliance. Failure to do so may result
	in insufficient gas volume supplied to the
	appliance.
	If a pressure drop of more than 2" water
NOTICE
	column occurs between Standby (static)
	Mode and Operating (dynamic) Mode, a
	gas volume problem exists. Contact the gas
	utility, gas supplier, qualified installer, or
	service agency to determine the necessary
	steps to provide the proper gas volume to
	the appliance.

How the control module operates

The SMART SYSTEM control module receives input from appliance sensors and external devices. The control module activates and controls the blower and gas valves to regulate heat input and switches the boiler, Domestic Hot Water (DHW), and system pumps on and off as needed. The user programs the module to meet system needs by adjusting control parameters. These parameters set operating temperatures and appliance operating modes. Boiler operation can be based on boiler outlet water temperature, boiler inlet water temperature, system supply temperature, or system return temperature, depending on the parameter setting. Water heater operation can be based on a tank sensor or a tank thermostat.

0 - 10V input (set point or power)

The Copper-fin II 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.

DHW priority (boiler only)

The SMART SYSTEM control module allows connection of a DHW thermostat or tank sensor to the low voltage connection board. When the DHW thermostat or tank sensor calls for heat, the module activates the DHW pump, shuts down the boiler pump, and immediately sets the target outlet water temperature to 180°F (82.2°C). This provides automatic priority heat allocation to the indirect water heater for maximum response and recovery. The DHW pump continues for 30 seconds after the heating cycle to deliver the most possible heat.

DHW / SH (space heating) cycling (boiler only)

If an indirect DHW call for heat is received while a space heating call is in progress, the control will start the DHW pump and shut the boiler pump off. The system pump will remain on. If the space heating call is still active while the DHW call is in operation, the control will wait for 30 minutes (time adjustable by installer) then it will switch back to the space heating demand. The control will switch back and forth until one of the heat demands end.

Programmable controlling sensor (boiler only)

The control module is programmed to use the outlet sensor as the control sensor by default. If a system supply sensor is connected, the control automatically uses it as the control sensor. The control sensor can be changed by the installer to the inlet sensor. In this case, if a system return sensor is installed, the control automatically uses it as the control sensor. If the inlet sensor is chosen as the controlling sensor, it is recommended that the system supply sensor be installed for the best system performance.

Anti-cycling (boiler only)

After the set point has been satisfied, the control will delay the next burner cycle for a set time period (time is adjustable by the installer). The time delay will be bypassed if the system return temperature drops too far during the delay.

Control inputs and outputs

Staging S1 - S4

The S1 input tells the boiler to provide water for space heating. The S2 - S4 inputs are used when a sequencer controls the boiler.

Tank Aquastat

This input tells the boiler to provide water for heating a domestic hot water tank.

Boiler, system, and DHW pump control

When a space heating call for heat starts and no DHW call is on, the system and boiler pumps are turned on. As long as the space heating call for heat is on, the system pump will remain on. If a DHW call for heat is on, the boiler pump will wait to turn on until just before the DHW pump turns off. After the space heating call for heat ends, both pumps will run for an additional period of time.

When a DHW call for heat starts, the DHW pump is turned on. If a space heating call for heat was on, the boiler pump will turn off a few seconds after the DHW pump turns on.

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