Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS Vent System Options, Negative Draft

Commercial Pool Heaters

INSTALLATION Continued

to the common air inlet. This exterior opening for combustion air must connect directly to the outdoors. The total length of the combined air inlet pipe must not exceed a maximum of 50 (15.2m) equivalent feet. Subtract 5 feet (1.5m) for each 90° elbow in the air inlet pipe. You must deduct the restriction in the area provided by any screens, grills or louvers installed in the common air inlet point. These are common on the sidewall air inlet openings. Screens, grills or louvers installed in the common air inlet can reduce the free area of the opening from 25% to 75% based on the materials used.

Vent System Options

This pool heater has six venting options.

1. Conventional Negative Draft Venting

This option uses a vertical rooftop flue termination. Combustion air is supplied from the mechanical room.

2. Vertical DirectAire™ Venting

This option uses a vertical conventional vent for flue products. Combustion air is supplied by a pipe from the sidewall or rooftop. See page 16 for venting details.

3. Sidewall Venting

This option uses a powered vent assembly to exhaust the flue products out a sidewall vent termination. Combustion air is supplied from the mechanical room. See page 17 for venting details.

4. Horizontal DirectAire™ Venting

This option uses a powered vent assembly to exhaust the flue products out a sidewall. Combustion air is supplied by a pipe from the sidewall. See page 20 for venting details.

5. Direct Venting

This option uses a sealed AL29-4C flue and a separate combustion air pipe to the outdoors. This system terminates both the flue and combustion air inlet in the same pressure zone. The flue outlet and combustion air intake may terminate at either a sidewall (horizontal) or the rooftop (vertical). See page 21 for venting details.

6. Outdoor Installation Venting

This option uses the installation of a special air inlet/vent cap on top of the pool heater. See page 25 for venting details. All pool heaters are shipped from the factory equipped for conventional negative draft venting. All other optional vent systems require the installation of specific vent kits and venting materials. The following is a detailed explanation of the installation requirements for each venting system, components used and part numbers of vent kits for each model.

Barometric Damper Location

Any venting system option that requires a barometric damper must adhere to the following directions for optimum performance.

The preferred location for the barometric damper is in a tee or collar installed in the vertical pipe rising from the pool heater’s flue outlet. The barometric damper MUST NOT be installed in a bull head tee installed on the pool heater’s flue outlet. The

tee or collar containing the barometric damper should be approximately three feet vertically above the connection to

the pool heater’s flue outlet. This location ensures that any positive velocity pressure from the pool heater’s internal combustion fan is dissipated and the flue products are rising due to buoyancy generated from the temperature of the flue products. Adjust weights on the damper to ensure that draft is maintained within the specified range.

1.Conventional Negative Draft Venting

IMPORTANT: Before installing the venting system, follow all venting clearances and requirements found in the Venting, General Information section, page 10.

Figure 17 – Conventional Negative Draft Vertical Venting with Combustion Air Louvers

This option uses Type-B doublewall flue outlet piping. The blower brings in combustion air. The buoyancy of the heated flue products cause them to rise up through the flue pipe. The flue outlet terminates at the rooftop.

Negative Draft

The negative draft in a conventional vent installation must be within the range of 0.02 to 0.08 inches w.c. to ensure proper operation. Make all draft readings while the pool heater is in stable operation (approximately 2 to 5 minutes).

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