User`s manual

—
7
—
IV. FIELD CONNECTIONS
A. External Trap Condensate Drain
The unit’s
3
/
4
-in. condensate drain connections are located
on the bottom and side of the unit. Unit discharge connec-
tions do not determine the use of drain connections; either
drain connection can be used with vertical or horizontal
applications.
When using the standard side drain connection, make sure
the plug in the alternate bottom connection is tight before
installing the unit.
To use the bottom drain connection for a roof curb installa-
tion, relocate the factory-installed plug from the bottom con-
nection to the side connection. See Fig. 7. The piping for the
condensate drain and external trap can be completed after
the unit is in place.
All units must have an external trap for condensate drain-
age. Install a trap at least 4-in. deep and protect against
freeze-up. See Fig. 8. If drain line is installed downstream
from the external trap, pitch the line away from the unit at 1
in. per 10 ft of run. Do not use a pipe size smaller than the
unit connection (
3
/
4
-in.).
B. Install Flue Hood
Flue hood is shipped screwed to the burner compartment
access panel. Remove from shipping location and, using
screws provided, install flue hood and screen in location
shown in Fig. 3 and 9.
C. Gas Piping (Fig. 10)
The gas supply pipe enters the unit through the access hole
provided. The gas connection to the unit is made to the
1
/
2
- or
3
/
4
-in. FPT gas inlet on the manual shutoff or gas valve.
Install a separate gas supply line that runs directly from the
meter to the heating section. Refer to NFGC for gas pipe siz-
ing. Do not use cast iron pipe. Check the local utility for rec-
ommendations concerning existing lines. Choose a supply
pipe that is large enough to keep the pressure loss as low as
practical. Never use pipe smaller than the
1
/
2
-in. FPT gas
inlet on the unit gas valve. See Table 1 for specific unit pipe
size.
For natural gas applications, the gas pressure at unit gas
connection must not be less than 4 in. wg or greater than
13 in. wg while the unit is operating. For liquid propane
applications, the gas pressure must not be less than 5 in. wg
or greater than 13 in. wg at the unit connection.
When installing the gas supply line, observe local codes per-
taining to gas pipe installations. Refer to NFGC ANSI
Z223.1-1988 (in Canada, CAN/CGA B149.1, [2]-M86) or
NFPA 54-1988 in the absence of local building codes. Adhere
to the following pertinent recommendations:
NOTE: When installing gas piping to gas valve inlet, use
properly sized back-up wrench on gas valve inlet flange flats.
1. Avoid low spots in long runs of pipe. Grade all pipe
1
/
4
inch in every 15 ft to prevent traps. Grade all hori-
zontal runs downward to risers. Use risers to connect
to heating section and to meter.
2. Protect all segments of piping system against physi-
cal 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 connec-
tions. Use only pipe dope that is resistant to action of
liquefied petroleum gases as specified by local and/or
national codes. Never use Teflon coated tape.
4. Install sediment trap in riser leading to heating sec-
tion. This drip leg functions as a trap for dirt and con-
densate. Install trap where condensate cannot freeze.
Install this sediment trap by connecting a piping tee
to riser leading to heating section, so that straight-
through section of tee is vertical (see Fig. 11). Then,
connect capped nipple into lower end of tee. Extend
capped nipple below level of gas controls.
DRAIN PLUG
NOTE:
Drain plug is shown in factory-installed position.
Fig. 7 — Condensate Drain Pan
NOTE:
Trap should be deep enough to offset maximum unit static differ-
ence. A 4-in. trap is recommended.
Fig. 8 — External Trap Condensate Drain
Fig. 9 — Flue Hood Details