Application Considerations
Horizontal Discharge
The typical rooftop installation has both the supply and
return air paths routed through the roof curb and building roof. However, many rooftop
installations require horizontal supply and/or return from the rooftop because of a
building’s unique design or for acoustic considerations.
Trane has two ways to accomplish horizontal supply and/or
return. The first applies to all IntelliPak® Rooftop units. Special field supplied curbs
are installed that use the unit’s standard discharge and return openings. The
supply and return air is routed through the curb to horizontal openings on the sides of
the curb. The second method available for horizontal supply and return applies to SXHF,
SLHF, SSHF, SXHG, SLHG and SSHG design units ONLY. With this method the standard
discharge and return openings are blocked in the field. Access panels are removed as
indicated in Figures 13-1 and 14-1. These openings are used for the discharge and return. This
method can only be applied to extended casing/cooling only, hot water or steam heat units.
No special curb is needed.
Figure 13-1 is a simplified sketch of the rooftop showing
which panels can be used for horizontal supply and/or return. To supply air horizontally,
the panels that normally house the heat accessory controls (Panel A) and the gas heat
barometric dampers (Panel B) can be removed and either of the openings used as a unit
discharge. To return air horizontally, the exhaust fan access door (Panel C) can be
removed and used as a return opening. Tables 13-1, 2 and 3 show dimensions for those
panels.
- Horizontal Discharge On SXHF, SLHF and SSHF Rooftops (20
through 75 tons)
The SXHF (extended casing cooling only), SSHF (steam heat)
and SLHF (hot water heat) rooftops can be field modified to supply and return air
horizontally without the use of a horizontal supply/ return curb.
To supply air horizontally on SXHF only, the panels that
normally house the heat accessory controls (Panel A) and the gas heat barometric dampers
(Panel B) can be removed and either of the openings used as a unit discharge. To
return air horizontally, the exhaust fan access door (Panel C) can be removed and used as
a return opening.
Note 1) For horizontal discharge on SLHF and SSHF units,
only the Panel B can be removed. Panel A cannot be used due to the location of the heating
coils.
Note 2) Supply and Return Base openings must be covered when
converting to a horizontal configuration.
Figure 13-1 Horizontal Discharge Panel Dimensions —
SXHF, SLHF, SSHF Units
Table 13-1 — SXHF, SSHF, SLHF — Panel A and B
Dimensions
Total
Area (H X W) |
| Model |
H (in.) |
W(in.) |
(in2) |
(ft2) |
| S*HF C20 |
40.7 |
25.5 |
1038 |
7.2 |
| S*HF C25 |
40.7 |
25.5 |
1038 |
7.2 |
| S*HF C30 |
52.7 |
25.5 |
1344 |
9.3 |
| S*HF C40 |
64.5 |
34.5 |
2225 |
15.5 |
| S*HF C50 |
76.7 |
34.5 |
2646 |
18.4 |
| S*HF C55 |
76.7 |
34.5 |
2646 |
18.4 |
| S*HF C60 |
64.6 |
34.5 |
2229 |
15.5 |
| S*HF C70 |
64.6 |
34.5 |
2229 |
15.5 |
| S*HF C75 |
64.6 |
34.5 |
2229 |
15.5 |
Table 13-2 — SXHF, SSHF, SLHF — Panel C
Dimensions
Total Area (H X W) |
| Model |
H (in.) |
W (in.) |
(in2) |
(ft2) |
| S*HF C20 |
40.7 |
34.5 |
1404 |
9.8 |
| S*HF C25 |
40.7 |
34.5 |
1404 |
9.8 |
| S*HF C30 |
52.7 |
34.5 |
1818 |
12.6 |
| S*HF C40 |
64.5 |
34.5 |
2225 |
15.5 |
| S*HF C50 |
76.7 |
34.5 |
2646 |
18.4 |
| S*HF C55 |
76.7 |
34.5 |
2646 |
18.4 |
| S*HF C60 |
64.6 |
34.5 |
2229 |
15.5 |
| S*HF C70 |
64.6 |
34.5 |
2229 |
15.5 |
* = X, L, or S
Table 13-3 — SXHF, SSHF, SLHF — X, Y and Z
Dimensions
| Model |
X (in.) |
Y (in.) |
Z (in.) |
| S*HF C20 |
35.5 |
44.0 |
201.5 |
| S*HF C25 |
35.5 |
44.0 |
201.5 |
| S*HF C30 |
35.5 |
56.0 |
201.5 |
| S*HF C40 |
44.5 |
67.8 |
237.0 |
| S*HF C50 |
44.5 |
80.0 |
237.0 |
| S*HF C55 |
44.5 |
80.0 |
237.0 |
| S*HF C60 |
44.5 |
68.0 |
237.5 |
| S*HF C70 |
44.5 |
68.0 |
237.5 |
Notes:
1. Add an extra 0.20-inches pressure drop to the supply
external static to account for the extra turn the air is making.
2. The openings all have a 1.25-inch lip around the
perimeter to facilitate ductwork attachment.
3. If exhaust fans are being used, provisions should be
made for access to the exhaust components, since the access door is now being used as a
return.
4. Use the dimensions provided and the supply Cfm to
calculate the velocity (ft/min) through the openings to be sure they are acceptable. |
