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Measurement Testing
A Resource Dedicated to Environmental Testing, EMC Testing, Vibration Testing and related areas
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Mjr
Site Admin
Joined: 13 Jul 2005
Posts: 294
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 Posted: Tue Nov 27, 2007 12:54 pm Post subject: Maintaining and Recertifying Environmental Test Chambers |
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This guide is also useful when purchasing Used or Refurbished Environmental Test Chambers.
Choose a reputable company -- one with trained and certified technicians -- to purchase a used chamber recertify your existing test chamber.
A checklist of items techs look at and test are:
Refrigeration System Checklist -- inspect the following and repair/replace as necessary:
System refrigerant charges checked to make sure they are within spec..
Compressor oil replaced.
All filter dryers replaced.
Refrigeration valves replaced with rapid-cycle valves unless already existing.
Oil separators replaced unless existing deemed clean.
Pressure switches added for compressor safety unless already existing.
Flush refrigeration system w/ nitrogen to eliminate old oil in lines.
Pressure-test system to find leaks.
Pull vacuum on system to find leaks.
Charge system with new environmentally-friendly refrigerants. E.g. R404a and R508b.
Refrigeration evaporator coils
Condenser unit
Compressors
Electrical Checklist -- inspect the following and repair/replace as necessary:
Contactors, relays
Heaters
Fan motors
Lights, lamps
Wiring, connectors, harnesses
Controllers -- inspect the following and repair/replace as necessary:
Older style controllers without tech. support retrofitted with new controllers
Wiring reconfigured to fit new controller
Controllers tuned for best performance.
Chambers larger than 5 cubic ft. equipped with over temperature-protection controller
General inspections and/or revamp:
All Window
Castors (wheels)
All sheet metal components
Humidity system boilers disassembled + cleaned; Inspect Heating elements + floats
Demineralizer cartridges -- replace.
Door gaskets
Chamber prepped for paint and repainted
Labels applied to chamber as necessary
Chamber re-tested after being painted.
Multiple test profiles run on chamber to ensure reliability. Customer-supplied tests also run upon request Chart results given to customer to verify test results.
Final checkout to ensure that chamber meets original manufacturers specs.
Optional Tests/Services:
Extended warranty
Original compressors replaced with new
Certified calibration
Startup and training
Retrofit from water cooled to air-cooled or visa versa.
Retrofit with accessories such as:
Chart Recorder
Dehumidifier
Feed-Through Ports
Extra Shelves
Water Recycling System
Heat Boost for Faster Temperature Ramp-Up Rates.
LN2 or CO2 Boost for Faster Temperature Ramp-Down
Rates.
Castors if not already existing.
Window installed if not already existing.
Extra event outputs from controller to interface to product
under test.
RS-232 or IEEE-488 Interface to Controller.
GN2 Purge
Be sure to ask about the Warranty of a used/recertified chamber or the work done on your existing chamber.
Period: Commonly 90 days parts + labor within the United States.
Location: Will Warranty work be provided at customer’s location – No need to return equipment unless under certain circumstances.
Is an Extended warranty available? |
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