2-3
to the supplied power cord. For 220 volt operation the plug must have at least a
250 V, 20 Ampere rating; for 120 volt operation the plug must have at least a
120V, 30 Ampere rating. As a minimum plugs will be UL listed for use in the
US, or CE marked for use in Europe.
Cooling Water
Cooling water is not necessary for some applications. If the furnace will be used
for medium temperature soldering applications such as gold/tin, (peak
temperature typically 330 °C), and enough time is available between runs for the
furnace to sufficiently cool off, cooling water will not be needed.
• There are two criteria that must be met for operation without cooling water:
1. The outer temperature of the chamber and view port housing must not be
allowed to operate above 110 °F (43 °C).
2. The sight glass must not be allowed to exceed a temperature of 200 °F
(93 °C). The sight glass is designed to operate at higher temperatures but
the O-rings that seal the sight glass to the vacuum chamber will
eventually fail.
• When cooling water is required it is to be connected to the furnace through
the 3/8-NPT female connectors marked “Water In” and “Water Out.” A flow
rate of one gallon-per-minute is required for maximum temperature
operations. The water temperature should be controlled within 5 °F (3 °C)
for best results and should be sufficiently above the dew point in the facility
to prevent condensation from forming on the lid, chamber, exhaust heat
exchanger, and piping. The suggested cooling water temperature to avoid
excessive thermal gradients is 68 °F (20 °C).
• If cooling water is not used the low flow switch must be disabled. Turn off
the power to the furnace, remove the furnace enclosure and open the rear
electrical panel. Locate a pair of wires from the flow switch, item 7, shown
on pictorial drawing “Cooling System Installation,” and disconnect it from
the furnace electrical system. Locate the supplied jumper (P/N 35804) and
connect it to the wires leading to the electrical panel. This procedure
bypasses the flow switch allowing the furnace to run without cooling water.
• If the optional CW-5 cooling system was purchased for this installation there
will be specific instructions included with the unit. Generally these self-
contained cooling units require little more than connecting the supply and
return lines to the furnace, filling with coolant, and connecting to an
electrical outlet.
• Note: It is important to understand that the cooling system contains
aluminum, copper, brass, and stainless steel components that must be
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