SPX Cooling Technologies 92-1322C User Manual
Marley Electric Basin Heater
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User Manual 92-1322C
/ Receiving and Inspection /
The heater package is shipped directly from the vendor.
1. Check all parts for any damage in transit. The carrier is responsible
for the condition of the heater package upon arrival. If damage is appar-
ent, note the freight bill accordingly. This will support your claim with the
freight carrier.
2. Check the nameplate on the enclosure and verify that the heaters and
the control panel are rated for the correct voltage.
3. Check the watt rating on each element and verify the sum of all elements
is equal to the KW rating as ordered.
4. The control panel is nameplated for the maximum amperage that the
panel can safely control and may be equal to or greater than the actual
amperage required for your heater package. See Installation Instructions
on page 5 to calculate amperage required.
3
/ Introduction /
The purpose of a basin heater is to prevent water freezing in the cooling
tower basin during periods of shutdown or standby operation. The heater
system is sized according to tower model and location to give maximum
protection against water freezing in the cold water basin. This heating
system is not intended to protect the tower fill and other components
from icing. Refer to Marley Technical Bulletin # H-002 "Operating Cooling
Towers in Freezing Weather." Contact your Marley Sales Representative
for a copy of this publication.
The Marley basin heater system is manufactured by INDEECO, a leader
in immersion heating equipment. The system is referred to as a "heater
package" and consists of immersion heaters, a control panel and combina-
tion temperature / liquid level sensor with a 12'-0" cable length. The basic
control panel contains a contactor(s) of sufficient capacity for the heater
elements selected. In addition the panel contains a transformer to reduce
line voltage to 24VAC for panel control power, and a solid state relay card
to detect low temperature and low water conditions. The panel enclosure
is rated NEMA 4X (liquid tight, noncorrosive) and the sensor cable is UL
outdoor rated. The sensor probe is stainless steel with 1⁄2" NPT threads
and a PVC bulkhead fitting for installation in the cold water basin.
Warning
Caution
Note
The panel may control more than one heating element, up to its nameplate
KW rating for the voltage and phase stated. In addition to the components
of the basic panel described above, available options are fusing, circuit
breakers or disconnect switches. The circuit diagram located on the inside
of the panel cover will indicate the panel configuration.
The following defined terms are used throughout this manual to bring at-
tention to the presence of hazards of various risk levels, or to important
information concerning the life of the product.
Indicates presence of a hazard which can cause severe personal
injury, death or substantial property damage if ignored.
Indicates presence of a hazard which will or can cause personal injury
or property damage if ignored.
Indicates special instructions on installation, operation or maintenance
which are important but not related to personal injury hazards.
4
/ Installation /
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Note
Caution
For detailed information concerning installation, refer to the heater
installation drawing provided with the cooling tower.
Heater Element
Install the heater element(s) in the depressed area of the cold water basin
near the outlet. Provide clearance of 7⁄8" or more above the floor.
A single centrally located heater can protect up to 300 square feet of basin
surface area from ice damage. To protect larger surface areas, position
several heaters so they protect equal areas. For multicell towers, no more
than two cells may be protected by a single heater package. For three or
more cells additional heater packages are necessary.
The heater should never operate out of the water. It would become
extremely hot (1500°F) and destroy the heater element and/or ignite nearby combustible materials. As a precaution and to prevent
fires when the clearance between any part of a heater element and
combustible materials is less than 10", install a sheet metal shield
to reflect and dissipate the heat. The shield must not contact the
heater element and should extend beyond the heater element in all
directions as shown in Table 1.
Table 1
Table 2
Heater Supports
Install metal supports for the heater element where necessary to keep
the unsupported length under 30". The number of supports required is
as shown in Table 2.
5
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