McLane now offers a pressure relief valve (PRV) upgrade to retrofit to all sampler controller housings for $400.00 (including installation by McLane but excluding shipping and insurance costs). The controller end-cap and anodizing must be in suitable condition for PRV retrofits.
The anodized aluminum controller housing contains alkaline battery packs (which are not manufactured by McLane). Though unlikely, an unsafe internal controller housing pressure is possible, resulting from the chemical reaction between alkaline electrolyte and anodized aluminum due to battery failure with or without the intrusion of seawater. Attention and care should be taken in maintaining, operating, and opening the pressure housing. There can be enough pressure to cause the endcap bolts to fail, especially when one or more are loosened or removed.
As with all pressure housings, special care should be taken with O-rings and associated surfaces. O-rings and surfaces should be cleaned with isopropyl alcohol. O-rings should be lubricated with provided Parker O-Lube and replaced when necessary. Spare O-rings are included in the tool kit, and more can be purchased from McLane. McLane is aware of only one occurrence of increased pressure causing the endcap bolts to fail, and its cause is unknown. The root cause of the failure will likely never be determined. A PRV retrofit would prevent any potentially problematic pressure differential but will not protect the electronics or housing from flooding or corrosion due to seawater or electrolytes. Instruments manufactured after May 2015 will have the PRV feature pre-installed. Contact McLane for more information.
