EXCEL 10 FCU CONTROLLER LNS PLUG-INS USER GUIDE

Fig. 10. Three-stage heating/cooling switching (defaults for switching levels and hysteresis shown)

Reheat Output

W7752D and F Controllers and the W7754P1000 have an additional high-current (10 A max.; UL916: 6 A max.) output relay to control an electric reheater (refer to Fig. 2 for sample application). The reheat output has its own switching level and hysteresis settings (see Fig. 11). The reheat relay may also be used as an auxiliary output for other purposes, in which case the controller must be configured to specify that the output is under network control instead of the FCU control algorithm.

Fig. 11. Reheat switching and hysteresis (defaults

shown)

Digital Input

The Excel 10 W7752 FCU Controllers are equipped with a single digital input which may be configured to accommodate an occupancy sensor, a window open/closed contact, an air flow detector (for fan failure detection), or a changeover input. It is possible to configure this input for either normally-open or normally-closed contacts for any of the switches.

The control algorithm in the Excel 10 FCU Controller uses the occupancy sensor, if configured, to determine the effective occupancy mode (see Table 3). If the Time Of Day (TOD) schedule indicates an occupied state, and the eccupancy

sensor contact is closed, the effective occupancy mode will be "occupied". However, if the TOD schedule indicates an occupied state and if the occupancy sensor contact is open, then the effective occupancy mode will be "standby". The control algorithm will then control according to the "standby" setpoints configured for the heating and the cooling modes.

Configuring the digital input for movement or no movement (dependent upon normally-open or normally-closed contacts) adds a delay of 15 minutes to the occupancy sensor such that the space is considered occupied until 15 minutes has elapsed since the last movement is detected.

If the digital input is configured to read input from a window open/closed contact, heating, cooling, and fan control will be disabled while the window is detected open. Frost protection will be enabled. A set of contacts may be wired in series for multiple windows. If the window open/closed contact is not configured, a one-to-one association (binding) of the window sensor from another controller on the LONWORKS network can be made. A locally-wired contact can also be used in combination with the network input, the result being a logical OR of the inputs.

If the digital input is configured to read input from an air flow detector (fan status), heating and cooling control will be disabled for a fan failure (fan ON and no air flow detected).

The input may also be configured for changeover for a two- pipe system.

The Excel 10 W7754 FCU Controllers are equipped with a second digital input which is permanently assigned (i.e. not configurable using the plug-in) to the window contact function.

EN2B-0285GE51 R0909

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Honeywell W7752D specifications Reheat Output, Digital Input
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W7752D specifications

The Honeywell W7752D is a versatile and advanced electronic gas combination control designed primarily for use in commercial heating systems. This product stands out for its ability to manage both gas ignition and safety functions, which are critical for maintaining the efficiency and safety of heating appliances. Its robust construction and advanced features make it a popular choice for HVAC professionals and service technicians.

One of the main features of the W7752D is its integration of multiple functions in a single device. It serves as both an automatic gas ignition control and a safety shut-off valve, which simplifies installation and reduces the need for additional components. This integrated design not only enhances reliability but also streamlines maintenance procedures.

Another notable technology utilized in the W7752D is its microprocessor-based control logic. This advanced technology allows for precise management of the ignition sequence, improving the overall efficiency of the heating system. The microprocessor enables the control to adapt to varying operating conditions, ensuring optimal performance even under changing demands.

The W7752D is equipped with features that enhance user-interface and diagnostics capabilities. It includes LED indicators that provide clear information about the operational status and any potential issues. This diagnostics capability facilitates easier troubleshooting, saving time and reducing the likelihood of extended downtimes.

Safety is a primary concern in gas appliances, and the W7752D addresses this with built-in safety mechanisms, including flame detection technologies. These features ensure that the appliance operates safely, automatically shutting down in case of any irregularities during operation. This emphasis on safety not only protects property but also provides peace of mind for users.

In terms of compatibility, the Honeywell W7752D is designed to work with a wide range of gas heating appliances. Its flexibility allows it to be used in various applications, making it suitable for different types of commercial environments. Additionally, the control complies with relevant safety and performance standards, ensuring reliable operation.

In summary, the Honeywell W7752D combines advanced technology with essential safety features, making it a top choice for commercial heating applications. Its integrated design, microprocessor-based control, user-friendly diagnostics, and robust safety mechanisms make it an essential component for efficient and safe gas heating systems. Whether it is for new installations or replacements, the W7752D provides HVAC professionals with the reliability and ease of use they demand.
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