Weil-McLain NX Inspect/Prepare Installation Site, Site Preparation, Pressure Switch Installation

Inspect/Prepare Installation Site

•Clearances to Burner and Appliance

Provide space around burner and appliance for ease of service and maintenance.

Check the minimum clearances against those shown by the appliance manufacturer and by ap- plicable building codes.

•Inspect Chimney or Direct Vent System

Inspect the chimney or vent. Make sure it is prop- erly sized and in good working condition. Follow the instructions supplied by the appliance manu- facturer.

Site Preparation

one near the bottom of the enclosure. Each open- ing must have a free area of not less than one (1) square inch per 1,000 BTU’s per hour of the total input rating of all appliances within the enclosure. The openings should have free access to the build- ing interior, which should have adequate infiltration from the outside.

Exhaust fans and other air-using devices: Size air openings large enough to supply all air-using devices in addition to the minimum size required for combustion air. If there is any possibility of the equipment room developing a negative pressure due to exhaust fans, clothes dryers, etc., either pipe combustion air directly to the burner or provide a sealed enclosure for the burner and supply it with its own combustion air supply.

•Combustion Air Supply Information

!Warning–Adequate Air

Supply Required

The burner cannot properly burn the fuel if it is not supplied with a reliable combustion air source. A non-reliable air source could result in incomplete combustion, causing sooting and possible carbon monoxide emission.

Possible Sooting &

Asphyxiation Hazard

S104

See NFPA Standard 31 for complete details.

•Safety Shutoff for Direct Vent System

The direct vent blocked flue safety shut off system, refer to Figure 2, shuts down the burner if the ex- haust flue is blocked and/or if the air inlet is blocked. It recognizes a blocked flue by sensing excessive pressure in the combustion chamber. It recognizes a blocked inlet by sensing excessive vacuum in the air inlet adapter.

This system meets the requirements for a blocked flue or blocked combustion air inlet per CSA Stan- dard B140.0. It is designed to interrupt the cad cell circuit and allow the control to shut down the burn- er.

Appliances located in confined spaces: All confined spaces should have two (2) permanent openings; one near the top of the enclosure and

•Direct/Sidewall Venting Application

For direct vent installations, follow instructions pro- vided with appliance and direct vent system. Out- side combustion air is required for direct venting.

Figure 2. Pressure Switch Installation
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WM 550-141-996/1105	Page 7
RWB 6104WMNX R1005