Lochinvar 400-801 service manual Cascade Offset, Minimum On/Off Time, Circulation pumps

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1 Service

The other Cascade divider method is Efficiency Optimization, designated as EFF in the menu. This method is used, as the name implies, when it is desired to have the most efficient system. When the first boiler reaches a certain rate (default = 90%), it lowers its rate to 45% and turns on the next boiler at 45%. The two (2) boilers then modulate at the same rate.

As the calculated load increases further and both boilers ramp up to 90%, it lowers the rate of the first two (2) boilers to 60% and brings the next boiler on at 60%. The three (3) boilers then modulate together. As the calculated load decreases, the boilers will reach a lower threshold (default = 30%), at which time the last boiler (the third in our example) will turn off and the Cascade will increase the rates of the remaining boilers to provide the equivalent total output as before ((3 x 30%) / 2 = 45% in our example).

Efficiency optimization is automatically selected when boilers of different sizes are programmed into the Leader control (see Boiler Size on this page).

Maximum Cascade Set Point

This parameter determines the set point used by the individual boilers in a Cascade when a system sensor is connected to the Leader boiler. When a boiler is commanded to fire by the Leader boiler, it will attempt to achieve this temperature at its outlet. The Leader boiler will limit the modulation of the last boiler to fire in order to hold the temperature at the system supply sensor to the user set point. If any of the boiler outlet temperatures reach the maximum cascade set point, the boiler will then modulate down on its own in order to keep its outlet temperature within the maximum cascade set point. Therefore, this parameter can be used to limit the outlet temperatures of all the boilers in a Cascade. Note that this parameter does not apply when the boiler is heating an indirect DHW tank. This parameter is adjustable by the installer by accessing the Maximum Cascade Set Point parameter. The temperature range of this parameter is 32° (0°C) to 190°F (88°C). The default maximum cascade set point is 185°F (85°C).

Cascade Offset

This parameter determines how much the temperature must go above set point before the lead boiler will turn off. This parameter can be adjusted by the installer by accessing the Cascade Offset parameter. The temperature range of this parameter is 0° to 20°F (11°C) The default value is 10°F (6°C).

Cascade Differential

This parameter determines how much the temperature must go below the turn off temperature (Set point + Offset) before the lead boiler turns on. This parameter can be adjusted by the installer by accessing the Cascade Differential parameter. The temperature range of this parameter is 0°F to 60°F (33°C) The default value is 20°F (11°C).

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Service Manual

Minimum On/Off Time

In order to prevent units in a Cascade from short cycling, this parameter defines the minimum ON and OFF time for each unit. The installer can adjust this time by accessing the Minimum On/Off Time parameter. The minimum setting is 0 seconds and the maximum setting is 10 minutes. The default is 30 seconds.

Minimum Next On Time

In order to reduce the risk of temperature overshoot with a Cascade, this parameter defines the minimum time delay from starting one unit until the next unit may be started. The installer can adjust this time delay by accessing the Minimum Next On Time parameter. The minimum setting is 0 minutes and the maximum setting is 10 minutes. The default is 60 seconds.

Boiler Size

When boilers of different sizes are connected together in a Cascade, the Leader boiler has to know the size of each boiler in that Cascade. The Boiler Size parameters allow the installer to program the size based on the Cascade address. This screen shows the Cascade address and the size of the boiler with that address (in BTU/hr):

1.When the Boiler Size screen is first accessed, Cascade Address 0 (Leader) is shown.

2.Press the NAVIGATION dial to access the first digit of the boiler size. Rotate the NAVIGATION dial to adjust the first digit. To access the next digit, press the NAVIGATION dial again. Continue this process until the correct boiler size (to the nearest 1000 BTU/hr) is shown. Press the RIGHT SELECT [SAVE] key.

3.Rotate the NAVIGATION dial to select the address of the next boiler in the Cascade. Repeat Step 2.

4.Once the size of the last boiler in the Cascade has been entered and saved, press the LEFT SELECT [EXIT] key to return to the Control Modes menu.

5.If no other parameters are to be adjusted, press the RIGHT SELECT [HOME] key to save the new settings and return to the Status screens.

The SMART SYSTEM control automatically uses the Efficiency Optimization Cascade type when controlling boilers of different sizes.

Circulation pumps

System Pump Delay

The system pump delay parameter sets the length of time the system pump (if connected) will run after a SH demand has been satisfied. This parameter is adjustable by the installer by accessing the System Pump Delay parameter. The time range for this parameter is 1 second to 40 minutes. The default time is 30 seconds.

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Contents Models 400 Contents Please read before proceeding Handling ceramic fiber materialsNiosh stated First Aid When servicing boiler What is in this manual? ServiceMaintenance TroubleshootingService Near boiler pipingKnight XL display Navigation DialControl inputs LOW Voltage Connection BoardSmart Control Module Control outputsAccess modes General OperationHow the boiler operates How the control module operatesOperation Display From previous page Sequence of Operation Display panel menu access Button Screen Operation Display StatusDisplay panel parameter access Button Screen Status Operation DisplayDescription See User Access Installer Access Display Modify Parameter tableMenu Resetoutdoor ANTI-CYCLING See User Access Installer Access Display Modify DescriptionTemperature units C / F Viewable and changeable control parametersTime and Date Software VersionTemperature Settings Data LoggingFunctions DHW Settings Outdoor Reset Anti-Cycling Control modes Cascade Offset Minimum On/Off TimeCirculation pumps Boiler Pump Delay DHW Pump DelayBoiler Pump Anti-Seize Delay DHW Pump Anti-Seize DelayService Notification Maintenance Maintenance and annual startup Service technicianOwner maintenance Maintenance Flue vent system and air piping Check water systemCheck expansion tank Check boiler relief valve Check ignition ground wiring Check all boiler wiringCheck control settings Inspect ignition and flame sense electrodesCheck flame signal Cleaning boiler heat exchangerReview with owner Model Kit Part Component Number DescriptionTest procedure Test low water flow conditionsTroubleshooting Before troubleshootingCheck the following Check control module fusesNo Display No BurnerOperation Unit DoesChecking temperature sensors Temperature Resistance Temperature ResistanceWire Color R/BK and Y Wire Color G and Y Resistance TemperatureNoisy No PumpBoiler Pump System PumpTroubleshooting Temp Sw OpenAnti-cycling Flame Fail IgnCont’d Flame SequenceOutlet Arhl Outlet MrhlFan Low/High Fan Speed LowHigh GV/RelayFault Sensor ShortedLouver Proving Inlet SensorFlue Sensor Fault Fatal ErrorMemory Error Flue Temp DiffFlue Temp High Delta T HighOutlet Temp Service Blk Watch Dog ErrorNo Error Stored Rem Ctrl FltCombustion Analysis Procedure Gas valve adjustment procedure ModelModels 601
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400-801 specifications

The Lochinvar 400-801 is a high-efficiency commercial boiler that embodies advanced engineering and cutting-edge technology. Designed for a variety of commercial applications, this boiler is known for its reliability, efficiency, and robust performance.

One of the standout features of the Lochinvar 400-801 is its high thermal efficiency, which can reach up to 99%. This efficiency not only reduces fuel consumption but also lowers operating costs, making it an economical choice for businesses seeking to minimize overhead. The boiler employs a stainless steel fire-tube heat exchanger that ensures optimal heat transfer and durability. This construction allows for enhanced resistance to corrosion, thereby extending the boiler's lifespan.

The Lochinvar 400-801 is equipped with advanced control technologies that enhance its performance. With its built-in SMART SYSTEM control, users can easily monitor and manage the boiler’s operations, optimizing performance while ensuring ease of use. This control system features a user-friendly interface that provides real-time data, including temperature settings, pressure readings, and operational status, allowing for quick diagnostics and efficient troubleshooting.

Safety is paramount in the design of the Lochinvar 400-801. The boiler includes a comprehensive safety system that incorporates multiple safety interlocks and a venting system that prevents backflow and ensures safe exhaust. Moreover, the unit is designed to operate with minimal noise, making it suitable for environments where noise reduction is crucial.

Installation and maintenance of the Lochinvar 400-801 are straightforward, thanks to its compact design and multiple venting options. The low-profile construction allows for flexibility in placement, making it an ideal fit for tight spaces. Maintenance tasks are simplified with accessible components, minimizing downtime and ensuring the system operates efficiently over its lifespan.

In conclusion, the Lochinvar 400-801 stands out in the commercial boiler market with its blend of efficiency, reliability, and innovation. With its advanced technologies and features, businesses can achieve significant energy savings while ensuring comfortable and consistent heat for various applications. The Lochinvar 400-801 is an investment in quality and performance, backed by a well-established brand in the heating industry. Whether for a new installation or a replacement, this boiler offers a comprehensive solution for commercial heating needs.
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