10 Operating information

General

How the boiler operates

The Crest uses an advanced stainless steel heat exchanger and electronic control module that allows fully condensing operation. The blowers pull in air and push flue products out of the boiler through the heat exchanger and flue piping. The control module regulates blower speeds to control the boiler firing rate. The gas valves sense the amount of air flowing into the boiler and allow only the right amount of gas to flow.

How the control modules operate

The Crest boiler is equipped with a SMART TOUCH control module. The SMART TOUCH control module receives inputs from boiler sensors and external devices. The control module activates and controls the blowers and gas valves to regulate heat input and switches the boiler, Hot Water Generator (HWG), and system pumps on and off as needed. The user programs the control module to meet system needs by adjusting control parameters. These parameters set operating temperatures and boiler operating modes.

Control inputs and outputs

Enable

This input tells the boiler to provide water for space heating.

Hot Water Generator (HWG) tank thermostat

This input tells the boiler to provide water for heating an indirect HW tank.

0 - 10V BMS input (set point or power)

The Crest 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.

0 - 10V System Pump speed input

When a variable speed system pump is used, and there is a 0 - 10V signal available from the pump speed control, this signal may be connected to the boiler. Doing so will allow the boiler to anticipate changes in the BTU’s needed by the system as the system flow changes, and therefore, help the boiler to maintain the desired system temperature. Connect the - input terminal to the COM or - output terminal on the pump speed control, and the + input terminal to the 0 - 10V or + output terminal on the pump speed control. Note that the voltage on these inputs must never go below ground.

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Installation & Operation Manual

HWG priority

The SMART TOUCH control module allows connection of a HW thermostat or sensor to the low voltage connection board. When the HW thermostat or sensor calls for heat, the control module activates the HW 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 HW Generator for maximum response and recovery. The HW pump continues for 60 seconds after the heating cycle to deliver the most possible heat. The control module can be programmed to limit the firing rate of the boiler during a HW call for heat.

Controlling sensor

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 module may be programmed to use the inlet sensor as the control sensor instead. In this case, the control will use the system return sensor if it is connected.

Anti-cycling

After a space heating demand has been satisfied, the control will delay the next space heating call for a set time period (time is adjustable by the installer). The time delay will be bypassed if the inlet water temperature drops too far during the delay.

Boiler, system, and HW pump control

When a space heating call for heat starts and no HWG call is on, the boiler pump is turned on. The system pump will turn on also if it is programmed to do so. If a HWG call for heat is on, the boiler pump will wait to turn on until just before the HWG pump turns off. After the space heating call for heat ends, the boiler pump will run for an additional period of time.

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

Louver

When the boiler needs to control combustion air louvers, connect a 24 VAC louver relay to the two (2) Louver Relay terminals. Connect the Louver End Switch to the Louver Proving Switch input on the Low Voltage Connection Board.

Temperature control

Modulation

The Crest is capable of modulating its firing rate from a minimum of 4 - 6% (model specific) to a maximum of 100%. The firing rate is dictated by the call for heat (i.e., space heating or hot water generation), the heating load, ramp delay (if enabled), and various other temperature limitations.

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Lochinvar 2.5, 3.5 service manual Operating information, General
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3, 2, 3.5, 2.5 specifications

The Lochinvar 2, 3, 3.5, and 2.5 models are a standout lineup in the realm of commercial and residential water heating solutions. Known for their advanced technology and high efficiency, these units cater to a wide range of applications, ensuring optimal performance and reliability.

One of the key features of the Lochinvar models is their robust construction. Each unit is designed to withstand rigorous operational demands while providing excellent thermal efficiency. They are equipped with stainless steel heat exchangers, which offer superior resistance to corrosion and extend the lifespan of the equipment. This durability is essential for both commercial and residential settings where demand can vary significantly.

The Lochinvar 2, 3, 3.5, and 2.5 models utilize innovative control systems that enhance their operational efficiency and user convenience. The built-in Smart Control technology allows for easy monitoring and adjusting of system parameters, ensuring that users can maintain optimal performance with minimal effort. This feature is especially beneficial in commercial settings where large volumes of hot water are required, as it enables users to effectively manage their energy consumption.

Energy efficiency is another hallmark of the Lochinvar lineup. With high-efficiency ratings, these models help reduce energy costs significantly, making them an environmentally friendly option for heating water. The use of advanced combustion technology ensures that these units can deliver maximum heat output with minimal fuel consumption.

Additionally, the Lochinvar models are designed with safety and reliability in mind. They feature multiple safety controls and diagnostics that alert users to potential issues before they escalate, providing peace of mind. The integration of advanced venting options allows for flexible installation configurations, accommodating various building layouts and space requirements.

In summary, the Lochinvar 2, 3, 3.5, and 2.5 models define modern water heating technology with their combination of durability, efficiency, and advanced features. With their innovative design and user-friendly controls, they meet the demanding needs of both commercial and residential users, making them a top choice in the water heater market. Whether for new installations or replacements, these units deliver reliable performance and value.
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