EXCEL 10 FCU CONTROLLER LNS PLUG-INS USER GUIDE

Fig. 15. Free topology LONWORKS layout examples

NOTE: See section "LONWORKS Termination" on page 23 for additional details.

IMPORTANT

Notes on Communications Wiring:

•All field wiring must conform to local codes and ordinances.

•Do not use different wire types or gauges on the same LONWORKS segment. The step change in line impedance characteristics would cause unpredictable reflections on the LONWORKS net- work. When using different types is unavoidable, use a Q7751A Router at the junction.

•Do not use shielded cable for LONWORKS wiring runs. The higher capacitance of the shielded cable will cause degradation of communications throughput. In noisy (high EMI) environments, avoid wire runs parallel to noisy power cables, or lines containing lighting dimmer switches, and keep at least 3 in. (76 mm) of separation between noisy lines and the LONWORKS cable.

•Make sure that neither of the LONWORKS wires is grounded.

Power Wiring

IMPORTANT

Notes on Power Wiring:

•All field wiring must conform to local codes and ordinances.

•See Table 10 for permitted wire sizes.

•To minimize EMI noise, do not run Triac and/or relay output wires in the same conduit as the input wires or the LONWORKS communications loop.

•To comply with CE requirements, in the case of devices having a voltage range of 50 to 1000 Vac or 75 and 1500 Vdc which are not provided with a supply cord and a plug or with other means for disconnection from the supply having a contact separation of at least 3 mm in all poles, the means for disconnection must be incorporated in the fixed wiring.

Step 4. Prepare Wiring Diagrams

General Considerations

The purpose of this step is to assist the application engineer in developing job drawings to meet job specifications.

NOTE: For field wiring, when two or more wires are to be attached to the same connector block terminal, be sure to twist them together. Deviation from this rule can result in improper electrical contact.

Table 10 lists wiring types, sizes, and length restrictions for Excel 10 FCU Controller products.

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EN2B-0285GE51 R0909

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Honeywell W7752D specifications Prepare Wiring Diagrams, Power Wiring, General Considerations
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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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