14
Fig. 17 — Thru-Base Gas Connection Fittings
The thru-base gas connector has male and female threads.
The male threads protrude above the basepan of the unit; the
female threads protrude below the basepan.
Check tightness of connector lock nuts before connecting
gas piping.
Install a
1
/
2
-in. NPT street elbow on the thru-base gas fit-
ting. Attach a
1
/
2
-in. pipe nipple with minimum length of
16-in. (406 mm) (field-supplied) to the street elbow and ex-
tend it through the access panel at the gas support bracket.
See Fig. 18.
Fig. 18 — Gas Line Piping for 3 to 6 Ton Units
Other hardware required to complete the installation of the
gas supply line includes a manual shutoff valve, a sediment
trap (drip leg) and a ground-joint union. A pressure regulator
valve may also be required (to convert gas pressure from
pounds to inches of pressure). The manual shutoff valve must
be located within 6 ft (1.83 m) of the unit. The union, located
in the final leg entering the unit, must be located at least 9 in.
(230 mm) away from the access panel to permit the panel to
be removed for service. If a regulator valve is installed, it
must be located a minimum of 4 ft (1220 mm) away from the
unit’s flue outlet. Some municipal codes require that the man-
ual shutoff valve be located upstream of the sediment trap.
See Fig. 19 and 20 for typical piping arrangements for gas
piping that has been routed through the sidewall of the curb.
See Fig. 21 for typical piping arrangement when thru-base is
used. Ensure that all piping does not block access to the unit’s
main control box or limit the required working space in front
of the control box.
Fig. 19 — Gas Piping, Typical Curb Sidewall Piping
(Example 1)
Fig. 20 — Gas Piping, Typical Curb Sidewall Piping
(Example 2)
Fig. 21 — Gas Piping, Typical Thru-Base
Connections
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR
BRASS FITTING FOR
3 TO 6 TON UNITS
AUXILIARY
POWER
SUPPLY
(OPTIONAL)
BRASS FITTING
FOR GAS PIPING
SUPPORT
BRACKET
EMBOSSMENT
9” (229mm) min
Union
Shut Off
Valve
Drip
Leg
Thru-Curb Adapter
Unit Base Rail
Drip
Leg
Shut Off
Valve
Union
Thru-Curb Adapter
Burner
Access
Panel
9” (229mm) min
Unit Base Rail
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