High Altitude Derate; Gas Piping Connections - Amana 10759833 Installation Instructions Manual

Two-stage variable speed

Table of Contents

When this furnace is installed at high altitude, the appropriate High Altitude orifice kit must be applied. This is required due

to the natural reduction in the density of both the gas fuel and combustion air as altitude increases. The kit will provide

the proper design certified input rate within the specified altitude range.

High altitude kits are purchased according to the installation altitude and usage of either natural or propane gas. Refer

to the product Specification Sheet for a tabular listing of appropriate altitude ranges and corresponding manufacturer's high

altitude (natural, propane gas, and/or pressure switch) kits.

Do not derate the furnace by adjusting the manifold pressure to a lower pressure than specified on the furnace rating plate.

The combination of the lower air density and a lower manifold pressure will prohibit the burner orifice from drawing the

proper amount of air into the burner. This may cause incomplete combustion, flashback, and possible yellow tipping.

In some areas the gas supplier may artificially derate the gas in an effort to compensate for the effects of altitude. If the

gas is artificially derated, the appropriate orifice size must be determined based upon the BTU/ft

gas and the altitude. Refer to the National Fuel Gas Code, NFPA 54/ANSI Z223.1, and information provided by the gas

supplier to determine the proper orifice size.

A different pressure switch may be required at high altitude regardless of the BTU/ft

product Specification Sheet for a tabular listing of appropriate altitude ranges and corresponding manufacturer's pressure

switch kits.

The gas piping supplying the furnace must be properly sized based on the gas flow required, specific gravity of the gas,

and length of the run. The gas line installation must comply with local codes, or in their absence, with the latest edition

of the National Fuel Gas Code, NFPA 54/ANSI Z223.1.

To connect the furnace to the building's gas piping, the installer must supply a ground joint union, drip leg, manual shutoff

valve, and line and fittings to connect to gas valve. In some cases, the installer may also need to supply a transition piece

from 1/2" pipe to a larger pipe size.

The following rules apply when installing piping:

1. Use black iron or steel pipe and fittings for the build-

ing piping.

2. Use pipe joint compound on male threads only. Pipe

joint compound must be resistant to the action of the

fuel used.

3. Use ground joint unions.

4. Install a drip leg to trap dirt and moisture before it

can enter the gas valve. The drip leg must be a mini-

mum of three inches long.

5. Install 1/8" NPT pipe plug fitting, accessible for test

gage connection, upstream of the gas supply con-

nection to the furnace.

6. Use two pipe wrenches when making connection to

the gas valve to keep it from turning. Maintain factory

shipped orientation.

7. Install a manual shutoff valve in a convenient loca-

tion between the meter and the unit within six feet of

unit. Any union installed, must be downstream of the

manual shutoff valve and located between the shut-

off valve and furnace.

8. Tighten all joints securely.

Gas Supply and Piping