Installation Piping; General Requirements; Connecting The Gas Supply Line To The Furnace Gas Train - Trane Voyager CV Installation And Maintenance Manual

Installation Piping

General Requirements

All internal gas piping for YC* rooftop units are factory
installed and leak tested. Once the unit is set into place, a
gas supply line must be field installed and connected to the
gas train located inside the gas heat compartment.
WARNING
Hazardous Gases and Flammable Vapors!
Exposure to hazardous gases from fuel substances have
been shown to cause cancer, birth defects or other
reproductive harm. Improper installation, adjustment,
alteration, service or use of this product could cause
flammable mixtures or lead to excessive carbon
monoxide. To avoid hazardous gases and flammable
vapors follow proper installation and set up of this
product and all warnings as provided in this manual.
Failure to follow all instructions could result in death or
serious injury.
Access holes are provided on the unit as shown in
Figure 11, p. 18 to accommodate side panel entry.
Following the guidelines listed below will enhance both
the installation and operation of the furnace.
Note: In the absence of local codes, the installation must
conform with the American National Standard
Z223.1a of the National Fuel Gas Code, (latest
edition).
1. To assure sufficient gas pressure at the unit, use
Table 18, p. 37 to determine the appropriate gas pipe
size for the heating capacity listed on the unit's
nameplate.
If a gas line already exists, verify that it is sized large
enough (Table 18, p. 37) to handle the additional
furnace capacity.
2. Take all branch piping from any main gas line from the
top at 90 degrees or side at 45 degrees to prevent
moisture from being drawn in with the gas.
3. Ensure that all piping connections are adequately
coated with joint sealant and properly tightened. Use a
piping compound that is resistant to liquid petroleum
gases.
4. Provide a drip leg near the unit.
NOTICE:
Gas Valve Damage!
• Failure to use a pressure regulating device will result
in incorrect gas pressures. This can cause erratic
operation due to gas pressure fluctuations as well as
damage to the gas valve.
• Oversizing the regulator will cause irregular pulsating
flame patterns, burner rumble, potential flame
outages, as well as possible gas valve damage.
36
5. Install a pressure regulator at the unit that is adequate
to maintain 6" w.c. for natural gas and 11" w.c. for LP
gas while the unit is operating in the "High Heat"
mode. A minimum inlet gas pressure of 2.5" w.c. for
natural gas and 8" w.c. for LP gas is required while
operating in the "High Heat" mode.
Note: Gas pressure in excess of 14" w.c. or 0.5 psig will
damage the gas train.
WARNING
Hazard of Explosion!
Never use an open flame to detect gas leaks. It could
result in an explosion. Use a leak test solution for leak
testing. Failure to follow recommended safe leak test
procedures could result in death or serious injury or
equipment or property-only-damage.
6. Leak test the gas supply line using a soap-and-water
solution or equivalent before connecting it to the gas
train.
7. Pressure test the supply line before connecting it to the
unit to prevent possible gas valve damage and the
unsafe operating conditions that will result.
Note: Do not rely on gas train shutoff valves to isolate
the unit while conducting gas pressure/leak
test. These valves are not designed to
withstand pressures in excess of 14" w.c. or 0.5
psig.
Connecting the Gas Supply Line to the
Furnace Gas Train
Follow the steps below to complete the installation
between the supply gas line and the furnace. Refer to
Figure 33, p. 37 for the Gas Train configuration.
1. Connect the supply gas piping using a "ground-joint"
type union to the furnace gas train and check for leaks.
2. Provide adequate support for the field installed gas
piping to avoid stressing the gas train and controls.
3. Adjust the inlet supply gas pressure to the
recommended 6" for natural gas or 11" w.c. for LP gas.
Table 17. Specific gravity multiplier
Specific Gravity Multiplier
0.5 1.1
0.55 1.04
0.6 1
0.65 0.96
RT-SVX34F-EN