3 8 |
Bosch 96% AFUE Gas Furnace
Installation, Operation & Maintenance
04.2019
|
Bosch Thermotechnology Corp.
Data subject to change
The following stipulations apply when connecting gas piping.
Use pipe joint compound on male threads only. Pipe joint compound
must be resistant to the action of the fuel used.
Use ground joint unions.
Install a drip leg to trap dirt and moisture before it can enter the gas
valve. The drip leg must be a minimum of three inches long.
Install a 1/8" NPT pipe plug fitting, accessible for test gage connection
immediately upstream of the gas supply connection to the furnace.
Use two pipe wrenches when making connection to the gas valve to
keep it from turning. The orientation of the gas valve on the manifold
must be maintained as shipped from the factory.
Install a manual shutoff valve between the gas meter and unit within six
feet of the unit. If a union is installed, the union must be downstream of
the manual shutoff valve, between the shutoff valve and the furnace.
Tighten all joints securely.
Connect the furnace to the building piping by one of the following
methods:
1.
Rigid metallic pipe and fi ttings.
2.
Semi-rigid metallic tubing and metallic fi ttings. Aluminum alloy
tubing must not be used in exterior locations.
3.
Use listed gas appliance connectors in accordance with their
instructions. Connectors must be fully in the same room as the
furnace.
4.
The installation of piping shall be in accordance with piping
codes and the regulations of the local gas company. Pipe joint
compound must be resistant to the chemical reaction with
liquefi ed petroleum gases.
When the gas piping enters through the right side of the furnace the installer must
supply the following fi ttings (starting from the gas valve):
90 degree elbows (2).
Close nipple.
Straight pipe to reach the exterior of the furnace.
A ground joint union, drip leg, and manual shutoff valve must also be supplied by
the installer. In some cases, the installer may also need to supply a transition piece
from 1/2" to another pipe size.
When the gas piping enters through the left side of the furnace, the installer must
supply the following fi ttings (starting from the gas valve):
Straight pipe to reach the exterior of the furnace.
A ground joint union, drip leg, and manual shutoff valve must also be
supplied by the installer. In some cases, the installer may also need to
supply a transition piece from 1/2 inch to another pipe size.
Figure 33
Location of Manual value
(Installed Ahead of Ground
Joint Pipe Union)
Height Required
By Local Code
Ground Joint Pipe Union
To Be Installed Ahead of
Gas Valve
Drip Leg
Reducing Coupling
1/2” x 1/8” with 1/8”
Pipe Plug To Measure
Line Gas Pressure
Typical Gas Pipe Arrangement
9.5 Gas Piping Checks
Before placing unit in operation, leak test the unit and gas connections.
WARNING: FIRE OR EXPLOSION HAZARD
Never test for gas leaks with an open fl ame. Use a
commercially available soap solution made specifi cally for
the detection of leaks to check all connections.
Check for leaks using an approved chloride-free soap and water solution, an
electronic combustible gas detector or other approved testing methods.
NOTICE:
Never exceed specified pressures for testing. Higher
pressures may damage the gas valve and cause
subsequent overfi ring resulting in heat exchanger failure.
This furnace must be isolated from the gas supply system by closing its manual
shutoff valve before pressure testing of gas supply piping system with test
pressures equal to or less than 1/2 psig (3.48 kPa).
