Application Considerations
Figure 14-1 is a simplified sketch showing which panels can
be used for horizontal supply and/or return. On all 90 through 130 ton units only one side
of the extended casing may be used for horizontal supply because of the location of the
unit control panel. There are, however, on SXHF models two panels (Panels A) on the side
opposite the control box which can be removed along with the vertical support which
separates the two. Removal of the vertical support is optional, but will ensure maximum
airflow. On SLHG, SSHG models only one of the Panel A’s may be used for horizontal
supply because of the location of the heating coil. Horizontal return is accomplished in
much the same way as on S*HFs by removing the exhaust fan access door (Panel B). See
Tables 14-1 and 2 for S*HG panel dimensions.
When using an IntelliPak® Rooftop for horizontal supply
and return, an additional pressure drop must be added to the supply external static to
account for the 90 degree turn the air is making. This additional pressure drop depends on
airflow and rooftop size, but a range of 0.10 inches to 0.30 inches can be expected. The
openings on the rooftop all have a one inch lip around the perimeter to facilitate
ductwork attachment. If exhaust fans are being used on an IntelliPak Rooftop unit with
horizontal return, provisions should be made for access to the exhaust components, since
the access door opening is now being used as a return. Perhaps the return ductwork
attachment to the rooftop can include a section of removable duct. Use the dimensions
provided and the supply and exhaust CFM to calculate the velocity (ft/min) through the
openings.
- Horizontal Discharge On SXHG, SLHG, SSHG Rooftops(90
through 130 tons)
The SXHG, SLHG, SSHG rooftops can be field modified to
supply and return air horizontally without the use of a horizontal supply/return curb.
To supply air horizontally, use Panel A only. The Panel on
the opposite side
Table 14-1 — SXHG, SLHG, SSHG —
Panel A and B Dimensions
Total Area (H X W)
| Panel |
H(in.) |
W(in.) |
(in.2) |
(ft |
| A |
72.7 |
27.5 |
1999 |
13.9 |
| B |
72.7 |
34.5 |
2508 |
17.4 |
Table 14-2— SXHG, SLHG, SSHG —
X, Y and Z Dimensions
| Model |
X(in.) |
Y(in.) |
Z(in.) |
| S*HG90-130 |
69.0 |
77.8 |
244.7 |
* = X, L, or S
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.
Figure 14-1 — Horizontal Discharge Panel Dimensions
— SXHG, SLHG, SSHG Units
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