Cambridge Air Solutions.
6
E-Series Technical Manual
Roof Top Configuration – E-Series
24" MOUNTING CURB
INLET DAMPER
RAINHOOD
W/ FILTERS
Fan Discharge Connections
To ensure the highest fan efficiency, duct turns and transitions must be made carefully, minimizing air friction losses
and turbulence. Proper ductwork installation, as outlined by such organizations as Sheet Metal and Air Conditioning
Contractors National Association, Inc. (SMACNA), should be followed closely.
PLUMBING / FILL AND DRAIN VALVES:
1. All installation should be performed in accordance to local and state codes and with proper permits.
2. The make-up water connection is ½” FPT.
3. Install a 3-way fill valve under the roof (in a conditioned space) to keep the pipe from freezing (see attached
schematic).
4. The 2-way drain valve can be installed outdoors or indoors under the roof line in a frost-free environment. See
schematic below. If the 2-way drain valve is installed outdoors (above the roof level), valve cover(s) are required.
Auto Drain with Freeze Protection (Optional)
Install a two-way drain valve on the sump’s drain connection. Install a three-way fill valve under the roof-line with
port “AB” piped to the make-up water connection from the sump. Port “A” is piped to the city water supply and port
“B” is piped to an approved roof drain. (See attached drawing.)
During normal operation of the unit the drain valve will be shut and the fill valve is open from port ”A” to port “AB”
letting city water enter the sump. Water level is adjusted and controlled by a float assembly to a level ½” inch below
the overflow. On a freeze signal or a signal from the 24-hour time clock, the drain valve will open allowing the sump
to drain. Simultaneously, the fill valve will shut off the city water, closing port ”A” to port “AB” but will open port
“AB” to port “B,” thus allowing the remaining water in the exposed pipe from the valve to the sump to drain to keep
the pipe from freezing. A low-water cut off switch will protect the pump(s) from running dry.
During installation, relocate the freeze stat bulb (located inside the electric control panel) to the outside of the
enclosure to ensure correct temperature readings.
