Greenheck Fan HRE-20 - Manual (Page 11)

11
1. Piping should be in accordance with accepted
industry standards. Pipework should be supported
independently of the coils. Water connections are
male NPT iron pipe. When installing couplings, do
not apply undue stress to the connection
extending through the unit. Use a backup pipe
wrench to avoid breaking the weld between coil
connection and header.
2. Connect the WATER SUPPLY TO THE BOTTOM
CONNECTION on the air leaving side and the
WATER RETURN TO THE TOP CONNECTION on
the air entering side. To insure proper venting, an
external air vent in the piping is recommended.
Connecting the supply and/or return in any other
manner will result in very poor performance. Be
sure to replace factory installed grommets around
coil connections if removed for piping. Failure to
replace grommets will result in water leakage into
the unit and altered performance.
3. The air vent at the uppermost point should be
temporarily opened during system start-up to
release all of the air from the coil. To maintain heat
transfer capacity, periodically vent any air in coil.
4. Water coils are not normally recommended for use
with entering air temperatures below 40 o F;
however, the energy recovery wheel maintains a
pre-coil temperature higher than 40
o F. No control
system can be depended on to be 100% safe
against freeze-up with water coils. Glycol
solutions or brines are the only safe media for
operation of water coils with low entering air
conditions.
CONTINUOUS WATER CIRCULATION THROUGH
THE COIL AT ALL TIMES IS HIGHLY
RECOMMENDED.
5. Pipe sizes for the system must be selected on the
basis of the head (pressure) available from the
circulation pump. The velocity should not exceed
6 feet per second and the friction loss should be
approximately 3 feet of water column per 100 feet
of pipe.
WATER COIL APPLICATION
RECOMMENDATIONS
Factory installed heating components are
mounted down stream of the energy wheel (and
direct evaporative cooler if supplied) on the
supply air side of the unit.
See FIGURE 10 for coil connection location. Coil
connections are located external to the unit as
shown. Coil connections that are not external
have been ordered from the factory with interior
or exhaust air stream coil connections.
FIGURE 10
Water coil
connections