Installation & Operation Manual

5 Electrical connections (continued)

Louver relay

Runtime contacts

When the heater is to control combustion air louvers, a field provided 24VAC louver relay must be installed. Connect the Louver Relay Coil terminals to the louver relay coil.

The SMART SYSTEM control closes a set of dry contacts whenever the burner is running. This is typically used by Building Management Systems to verify that the boiler is responding to a call for heat.

Louver proving switch

The operation of a louver proving switch needs to be verified before the boiler fires. Remove the jumper wire from these terminals and connect them to the normally open contacts on its proving switch (FIG. 5-4).

System supply sensor (recommended use)

1.By installing the system supply sensor into the supply of the primary loop, the temperature of the primary supply can be controlled. The SMART SYSTEM control automatically detects the presence of this sensor, and controls the boiler firing rate to maintain the system supply temperature to the set point (if the outlet sensor control is currently selected).

2.Connect these terminals to the system supply sensor (FIG. 5-4).

System return sensor (optional use)

1.By installing the system return sensor into the return of the primary loop, the temperature of the primary return can be sensed when a 3-way valve or other device is installed ahead of the heater inlet. The SMART SYSTEM control automatically senses the presence of this sensor. If the inlet sensor is selected as the controlling sensor, the SMART SYSTEM control will adjust the firing rate to hold the system return temperature to the set point. It is strongly recommended that the system supply sensor be installed as well.

2.Connect these terminals to the system return sensor (FIG. 5-4).

Boiler Management System (BMS)

1.An external control may be connected to control either the firing rate or the set point of the appliance (boiler or water heater). Connect the 0 - 10 VDC terminals to the 0 - 10 VDC output of the external control. The SMART SYSTEM control can be programmed to use the enable output of the Boiler Management System, or use the voltage signal to enable the heater. Connect the Staging S1 or tank thermostat terminals to the enable output of the BMS, when used.

2.Make sure the ground terminal is connected to the ground output terminal of the external control, and the 0 - 10 V BMS IN terminal is connected to the 0 - 10 VDC terminal of the external control.

3-way valve out

An electric 3-way mixing valve may be used when the return temperature to the heater is less than 140°F (60°C). Connect the Open output to the Open terminal on the 3-way valve. Connect the Close output to the Close terminal on the valve and the COM output to the 24VAC terminal on the valve.

0 - 10V rate out

A 0 - 10VDC signal is available to allow a Building Management System (BMS) to monitor the firing rate of the heater. Make sure the (-) terminal is connected to the (-) or common terminal of the external control, and the (+) terminal is connected to the

(+) or Vdc terminal of the external control.

0 - 10V system pump in

A 0 - 10VDC input is available so that the boiler can monitor the speed of a variable speed system pump. This allows the boiler to anticipate changes in the heat load as the system flow changes. Connect the (-) terminal to the (-) or common terminal on the system pump VFD drive, and the (+) terminal to the (+) or 0 - 10VDC terminal on the system pump VFD drive. A 0 - 020mA signal may also be used, by adding a 500 ohm resistor between the (+) and (-) terminals.

Sequencer

The individual stages in the heater can be controlled separately with an external sequencer. Connect the Staging S1 terminals to the first stage contacts on the sequencer, the Staging S2 terminals to the second stage contacts, and so forth. Note that the sequencer must enable the stages in order, with Stage 1 first, Stage 2 second and so on.

Alarm contacts

The SMART SYSTEM control closes another set of contacts whenever the heater is locked out or the power is turned off. This can be used to turn on an alarm, or signal a Building Management System that the boiler is down.

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Lochinvar 402 - 2072 Louver relay, Louver proving switch, System supply sensor recommended use, Way valve out, Sequencer
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402 - 2072 specifications

The Lochinvar 402 - 2072 is a versatile and highly efficient boiler designed to meet the heating demands of modern residential and commercial applications. This model stands out due to its innovative technologies, advanced features, and a high level of reliability, making it an ideal choice for consumers looking for an enduring and economical heating solution.

One of the primary characteristics of the Lochinvar 402 - 2072 is its impressive energy efficiency. With an exceptional annual fuel utilization efficiency (AFUE) rating, this boiler ensures minimal energy waste, allowing homeowners and business operators to save significantly on their energy bills. The model incorporates advanced condensing technology that enables it to extract heat from the combustion gases, maximizing heat transfer and reducing emissions.

The Lochinvar 402 - 2072 is built with a robust stainless steel construction that enhances durability and resilience against corrosion and other environmental factors. This material not only prolongs the lifespan of the unit but also contributes to its outstanding thermal efficiency. Additionally, the boiler's compact design allows for flexible installation options, making it suitable for various spaces, including tight utility rooms and basements.

Equipped with a user-friendly control interface, the Lochinvar 402 - 2072 allows for easy monitoring and adjustment of settings. Its advanced digital display provides real-time data on system performance, ensuring the operator can maintain optimal performance and efficiency.

Another noteworthy feature is the unit's quiet operation. The design includes sound-dampening insulation and high-efficiency circulators, keeping noise to a minimum, which is an essential trait for both residential and commercial settings.

The Lochinvar 402 - 2072 is also designed with safety in mind. It incorporates multiple safety features including an automated vent damper, low water cutoff, and a comprehensive control system that monitors various operating conditions. This proactive approach to safety ensures that potential issues are identified and addressed before they become critical.

In conclusion, the Lochinvar 402 - 2072 boiler presents an exceptional combination of efficiency, durability, and user-friendly features. Its advanced condensing technology, stainless steel construction, and focus on safety make it a leading choice in the competitive boiler market, catering to the heating needs of a diverse range of applications while ensuring environmental responsibility. For those in search of a dependable and efficient heating solution, the Lochinvar 402 - 2072 is certainly worth considering.
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