DESIGN ALERT ON HIGH VOLTAGE POWER FOR CHILLERS
ISSUE:
Problem of specifying 4160 (high) voltage for chillers.
BACKGROUND:
ProCATS (Proactive claims analysis and tracking system) shows a change order of
,000 was issued on a project to provide a separate 480 volt power source for chiller
oil pumps. The compressor starters were served by 4160 volt power source. There
were four chillers involved. The starters were free standing and not unit mounted.
DISCUSSION:
The VA master spec section 15650 "Refrigeration Equipment (HVAC)" calls for an
independent 120 volt power source for controls, oil pumps, and purge units etc. In
addition, normally, a 480 volt is specified for the compressor starters and the starters
are mounted on the chillers. With these two requirements and since most of the time
the unit mounted starters and controls are provided with built-in transformers, we do not
experience any problem with it. The starters for 4160 volts are heavier and some
manufacturers provide free standing type and not unit mounted type. Free standing
starters are field wired and can pose a problem if the contract spec does not call for a
transformer for oil pumps or a separate 480 volt or 120 volt power source depending
upon the pump size. VA master spec is weak in this area and needs updating.
RECOMMENDATIONS/CONCLUSION:
1. The HVAC Professional Group should discuss this item and come up with a solution.
Meanwhile, please be alert to this problem, and if you are using 4160 volt power for
chillers on your project, please make sure your A/E provides a proper design which is
also properly coordinated with the Electrical.
FOR ADDITIONAL INFOR MATION:
Contact Satish Sehgal at 202.565.5032 in the Standards Service (187C).
27 February 1995
FM-187C-DA30
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