3.Secure flue hood to flue panel by inserting a single screw on the right side and the left side of the hood.
VIII. INSTALL GAS PIPING
The gas supply pipe enters the unit through the access hole provided. The gas connection to the unit is made to the 1/2-in. FPT gas inlet on the manual shutoff or gas valve.
Install a gas supply line that runs to the heating section. Refer to Table 4 and the NFGC for gas pipe sizing. Do not use cast-iron pipe. It is recommended that a black iron pipe is used. check the local utility for recommendations concerning existing lines. Size gas supply piping for 0.5 in. wg maximum pressure drop. Never
use pipe smaller than the 1/2-in. FPT gas inlet on the unit gas valve.
For natural gas applications, the gas pressure at unit gas connection must not be less than 4.0 in. wg or greater than 13 in. wg while the unit is operating. For propane applications, the gas pressure must not be less than 7.0 in. wg or greater than 13 in. wg at the unit connection.
A 1/8-in. NPT plugged tapping accessible for test gauge connec- tion must be installed immediately upstream of the gas supply connection to the gas valve.
When installing the gas supply line, observe local codes pertaining to gas pipe installations. Refer to the NFGC ANSI Z223.1, NFPA 54 latest edition (in Canada, CAN/CGA B149.1, B149.2 latest edition). In the absence of local building codes, adhere to the following pertinent recommendations:
1.Avoid low spots in long runs of pipe. Grade all pipe 1/4 in. in every 15 ft. to prevent traps. Grade all horizontal runs downward to risers. Use risers to connect to heating section and to meter.
2.Protect all segments of piping system against physical and thermal damage. Support all piping with appropriate straps, hangers, etc. Use a minimum of one hanger every 6 ft. For pipe sizes larger than 1/2 in., follow recommendations of national codes.
3.Apply joint compound (pipe dope) sparingly and only to male threads of joint when making pipe connections. Use only pipe dope that is resistant to action of liquefied petroleum gases as specified by local and/or national codes. Never use Teflon tape.
4.Install sediment trap in riser leading to heating section per Fig. 10. This drip leg functions as a trap for dirt and condensate.
5.Install an accessible, external, manual main shutoff valve in gas supply pipe within 6 ft. of heating section.
6.Install ground-joint union close to heating section between unit manual shutoff and external manual main shutoff valve.
7.Pressure-test all gas piping in accordance with local and national plumbing and gas codes before connection of piping to unit.
NOTE: The supply piping must be disconnected from the gas valve during the testing of the piping systems when test pressure is in excess of 0.5 psig (13.8 WC). If the test pressure is equal to or less than 0.5 psig, the unit heating section must be isolated from the gas piping system by closing the external main manual shutoff valve and slightly opening the ground-joint union.
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CAUTION: Unstable operation may occur when the gas valve and manifold assembly are forced out of position while connecting improperly routed rigid gas piping to the gas valve. Use a backup wrench when making connection to avoid strain on, or distortion of, the gas control piping.
CAUTION: If a flexible conductor is required or al- lowed by the authority having jurisdiction, black iron pipe shall be installed at the gas valve and shall extend a minimum of 2 in. outside the unit casing.
WARNING: Never use a match or other open flame when checking for gas leaks. Never purge gas line into combustion chamber. Failure to follow this warning could result in an explosion causing serious injury or death
8.Check for gas leaks at the field-installed and factory- installed gas lines after all piping connections have been completed. Use soap and water solution (or method speci- fied by local codes and/or regulations).
IX. INSTALL DUCT CONNECTIONS
The unit has duct flanges on the supply- and return-air openings on the side and bottom of the unit. For downshot applications the ductwork can be connected to the roof curb. See Fig. 6 and 7 for connection sizes and locations.
CONFIGURING UNITS FOR DOWNFLOW (VERTICAL) DIS- CHARGE
WARNING: Before performing service or maintenance operations on the system, turn off main power to unit. Electrical shock could cause serious injury or death.
1.Open all electrical disconnects before starting any service work.
2.Remove return duct cover located on duct panel by breaking connecting tabs with screwdriver and a hammer (Fig. 11).
3.To remove supply duct cover, break front and right side connecting tabs with a screwdriver and a hammer. Push louver down to break rear and left side tabs (Fig. 12).
4.If unit ductwork is to be attached to vertical opening flanges on the unit basepan (jackstand applications only), do so at this time. Collect ALL screws that were removed. Do not leave screws on rooftop as permanent damage to the roof may occur.
5.It is recommended that the basepan insulation around the perimeter of the vertical return-air opening be secured to the basepan with aluminum tape. Applicable local codes may require aluminum tape to prevent exposed fiberglass.
6.Cover both horizontal duct openings with the duct covers from the accessory duct cover kit. Ensure opening is air-and watertight.
7.After completing unit conversion, perform all safety checks and power up unit.
NOTE: The design and installation of the duct system must be in accordance with the standards of the NFPA for installation of nonresidence-type air conditioning and ventilating systems, NFPA 90A or residence-type, NFPA 90B; and/or local codes and residence-type, NFPA 90B; and/or local codes and ordinances.
