Outdoor reset operation, if used, Cascade

Outdoor Knight XL Installation & Operation Manual

8 Operating information

Low water cutoff protection

1.The SMART SYSTEM control module uses temperature sensing of both supply and return areas of the heat exchanger. If the ﬂow rate is too low or the outlet temperature too high, the control module modulates and shuts the boiler down. This ensures boiler shutdown in the event of low water or low ﬂow conditions.

2.Some codes and jurisdiction may accept these integral features of the control in lieu of requiring an additional limit control or low water cutoff. Consult local jurisdiction to determine. A low water cutoff is available from the factory (WTR30024).

Outdoor reset operation, if used

Target temperature with outdoor reset

This feature improves the system’s efﬁciency as the outdoor temperature warms up.

See the Outdoor Knight XL Service Manual to change the settings.

Reset curve

The reset curves look at outdoor air temperature and adjusts the set points.

Cascade

When multiple boilers are installed, they can be wired together in a cascade sequence. A maximum of eight boilers can be controlled from a single control. In this application one boiler would be designated as the Leader control and all others would be designated as Member controls. The Leader control can be programmed to use Lead/Lag or Efﬁciency Optimization control methods.

Once the Leader boiler receives a call for heat from a room thermostat, BMS, or Modbus, the control will determine what the set point will be. If outdoor air reset is desired, connect the outdoor air sensor to the terminals on the Low Voltage Connection Board on the Leader boiler. The set point will be calculated based on the programmed reset curve parameters. See the Outdoor Knight XL Service Manual to program the reset curve. If outdoor air reset is not desired, do not connect the outdoor air sensor. A ﬁxed temperature set point can be programmed into the control. See page 59 of this manual to program the set point.

If the water temperature at the system supply sensor is less than the set point + the turn-off offset - the off-on differential, then the control will initiate a call for heat on the Cascade (see the Outdoor Knight XL Service Manual for an explanation of the offset and differential). The Leader will energize the lead boiler on the Cascade. For a new startup this will be the Leader boiler.

Sequence of the cascade

To equalize the run time of all boilers on the Cascade, the ﬁring sequence will automatically be changed at set intervals.

The sequence will be changed once every 24 hours. The switching on/off sequence will be as follows:

TIME	SWITCHING ON SEQUENCE

Start	L-M1-M2-M3-M4-M5-M6-M7

1 hour	M1-M2-M3-M4-M5-M6-M7-L

2 hours	M2-M3-M4-M5-M6-M7-L-M1

If a boiler locks out or is used to heat an indirect DHW tank, it will automatically be given the lowest priority for the rest of that 24 hour period.

DHW, Night Setback, and Ramp Delay operation with cascade

For normal mode DHW operation any boiler(s) in the Cascade can be selected to provide heat for a DHW call. Select a boiler to be designated as the DHW boiler. Connect the DHW thermostat or sensor to the terminals on the Low Voltage Connection Board marked for the corresponding device. When the boiler receives a DHW call, the Leader control will take that boiler out of the Cascade sequence. If another boiler is available, the Leader will start it up to take its place.

The DHW boiler will adjust its set point to the programmed DHW boiler set point and will adjust its ﬁring rate to maintain this. Once the DHW call has been satisﬁed, the Leader control will place that boiler back into the Cascade sequence.

Switching of the boiler between DHW operation and SH operation when there is a call for both does not occur in Cascade Mode.

When DHW is programmed for Zone Mode, connect the DHW thermostat or tank sensor to the Leader boiler. When a DHW call is received, the Leader will modulate the entire Cascade to bring the system supply temperature up to the DHW boiler set point (if higher).

Night Setback operation of the boilers within the Cascade is available. Programming of the Night Setback will be done through the Leader boiler. Refer to the Outdoor Knight XL Service manual for information regarding Night Setback.

Ramp Delay operation of the boilers as described in the Outdoor Knight XL Service Manual is available when the boilers are part of a Cascade system.

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.

Lochinvar 400-801 operation manual Outdoor reset operation, if used, Cascade

Models: 400-801