Liebert Mini-Mate2 MMD24E - OPTIONAL EQUIPMENT PIPING; Free-Cooling Coil and Hot Water Reheat Piping

Site Preparation and Installation
Liebert
®
Mini-Mate2
™
40
5.9 Optional Equipment Piping
5.9.1 Free-Cooling Coil
The free-cooling coil is a secondary coil located downstream of the DX coil. The free-coiling coil does
not operate at the same time as the DX coil. A temperature sensor is factory-mounted to the free-
cooling piping. If the water temperature is less than the set temperature (usually 45°F [7.2°C]), the 3-
way valve opens to allow chilled water flow to the free-cooling coil and the compressor is locked off. If
the water temperature is above the set temperature, the 3-way valve closes (bypasses) and enables
the compressor. To keep deposits from building up in the free-cooling coil, an adjustable timer is
factory-set to flush every 400 minutes.
On water-cooled systems, the free-cooling coil outlet can be field piped to the condensing unit inlet,
provided a 3-way regulating valve has been installed within the water/glycol condensing unit (see
Figure 24).
Figure 24 Optional free-cooling coil (3-way valve) on water/glycol units
NOTE
If the free-cooling coil is piped to an open water tower, a CU/NI (copper-nickel) type coil must
be ordered to prevent corrosion of the copper tubes; or a heat exchanger must separate the tower
water from the free-cooling loop.
Fluid
Return
From Unit
Fluid
Return
From
Unit
Fluid
Supply
To Unit
Temperature
Stat
Free-Cooling
Control
Valve
Bleed Valve
Free-Cooling
Coil
Shutoff*
Valves
Shutoff*
Valves
Hose*
Bibs
Hose*
Bibs
Fluid
Supply
To Unit
3-Way Water
Regulating
Valve
(Optional)
Tube in
Tube
Condense
r
DPN000219
Rev. 3
FIELD PIPING
NOTE: RECOMMENDED PIPING FOR UNITS
WITH FREE-COOLING COIL OPTION
AND WATER/GLYCOL CONDENSER.
* Components are not supplied by Emerson
but are recommended for proper circuit
operation and maintenance.
FACTORY PIPING