36
®
Model MSX Make-Up Air
Maintenance - Fall
Evaporative Coolers
The water should be shut off and all the lines drained
when the outside temperature drops below 45°F.
Remove drain plugs for the winter.
Clean all interior parts of any mineral deposits or foreign
materials that may have built-up during the cooling
season.
Replace any worn or non-functioning parts.
Winterizing Chilled Water Coils
During the winter, chilled water coils need to be
protected against freezing. Greenheck recommends
protecting the coils by either blowing-out the coils or
by flushing the coils.
Blowing-Out Coils
1. Close valves on the supply and return lines.
2. Open drain valves and/or drain plug. Remove
vent plug to allow coil to drain faster.
3. After coil is fully drained, connect a blower to the
caps. Do not connect the blower to the air vent
or drain plug.
4. Close the vent plug on the header that the blower
is connected to. Open the drain valve or cap on
the other header.
5. Turn on blower for 30 minutes. Place mirror at
discharge. If the mirror fogs up, repeat procedure
until no fog appears on the mirror.
6. After drying the coil, wait a few minutes then
repeat Step #5.
7. Leave drains open and do not install plugs until
beginning of cooling season.
Flushing Coils
Greenheck recommends the use of inhibited glycol
(such as propylene or ethylene) to flush water coils
to protect against freezing. Additionally, the use of
inhibited glycol provides corrosion protection.
The table below indicate the percentage of glycol
required to prevent freezing in a coil at a given outdoor
air freeze point. Completely fill coil with solution. Drain
coil. Residual glycol fluid per these concentrations
can be left in the coil without concern of freezing.
Recovered fluid can be used to flush other coils.
Percent of
Ethylene
Glycol
by Volume
Freeze Point
Percent of
Propylene
Glycol
by Volume
Freeze Point
°F
ºC
°F
ºC
0
32
0
0
32
0
10
25
-4
10
26
-3
20
16
-9
20
19
-7
30
3
-16
30
8
-13
40
-13
-25
40
-7
-22
50
-34
-37
50
-28
-33
60
-55
-48
60
-60
-51
