Greenheck MSX (470658) - Manual (Page 15)

15 Modular Supply Make-Up Air Unit
®
6 in. min.
6 in. min.
Drain
Trap
IMPORTANT
All traps must be installed below the roof line or be
otherwise protected from freezing.
Installation of Building Pressure Control
(optional)
1. Mount Pressure Tap. Using the factory provided
bracket, mount the pressure tap to the outside of the
unit. Choose a location out of the prevailing winds
and away from
supply or exhaust
fans to assure
accurate readings.
2. Run Pressure
Tap Lines. Run a
pressure tap line
from the pressure
tap on the outside of the unit to the low pressure tap
on the back of the photohelic gauge. Run a second
pressure tap line from the high pressure tap on the
back of the photohelic gauge to the space. Fifty feet
of tubing is supplied with the unit.
3. Set the Building Pressure. The pressure gauge
is used to set the desired building pressure. The
pressure is set by adjusting the knobs for the upper
and lower pressure limits. Typical settings are 0.0
inch wc for the lower and 0.10 inch wc for the upper
pressure setting.
Connections for Photohelic Gauge
Factory
Wiring
High Pressure
Tap
to Space
Low Pressure
Tap
to Outside
Typical Photohelic Gauge Settings
Pressure Setting Knobs
Pressure Setting
Needles
Pressure Indicating
Needle
IMPORTANT
Guidelines for the installation of the cooling coil have
been provided to insure proper performance of the
coils and their longevity. These are general guidelines
that may have to be tailored to meet the specific
requirements of any one job. As always, a qualified
party or individual should perform the installation and
maintenance of the coil. Protective equipment such
as safety glasses, steel toe boots and gloves are
recommended during the installation and maintenance
of the coil.
When installing couplings, do not apply undue stress
to the connection. Use a backup pipe wrench to avoid
breaking the weld between the coil connection and
the header.
All field piping must be self-supporting. System piping
should be flexible enough to allow for the thermal
expansion and contraction of the coil.
Installation of Chilled Water Coil Piping
(optional)
1. Verify Coil Hand Designation. Check the coil
hand designation to ensure that it matches the
system. Coils are
generally plumbed with
the supply connection
located on the bottom
of the leaving air-side of
the coil and the return
connection at the top
of the entering air-side of the coil. This arrangement
provides a counter flow heat exchanger and positive
coil drainage.
2. Check the Coil for Leaks. Pressurize the coil to
100 psig with dry nitrogen or other suitable gas. The
coil should be left pressurized for a minimum of 10
minutes. If the coil holds the pressure, the hook-up
can be considered leak free. If the pressure drops by
5 psig or less, re-pressurize the coil and wait another
10 minutes. If the pressure drops again there is likely
one or more small leaks which should be located and
repaired. Pressure losses greater than 5 psig indicate
a large leak that should be isolated and repaired.
3. Connect the Supply and Return Lines. Connect
the supply and return lines as shown above.
4. Install the Drain Line. Connect an unobstructed
drain line to the drain
pan. A trap should be
installed to prevent
sewer gas from being
drawn into the unit.
Hot Return
Connection
Cold Supply
Connection
Entering Air Leaving Air