User's Manual

Page 32
10.3 HRU replacement
If you have an EPIRB in an enclosure marked Category 1 then it contains a
Hydrostatic Release Unit (HRU). This has a 2 year replacement interval. WARNING:
Failure to replace the HRU at 2-yearly intervals may result in it not actuating
correctly and releasing the EPIRB in an emergency. The expiry date, which is
marked on the HRU and on the enclosure side label should be checked regularly.
When the HRU expires you can obtain a replacement at a local marine store; ask for a
McMurdo Ltd BreaktHRU HRU Replacement Kit (Part No. 82-962-001A). The kit is
complete with breakable plastic rod, date labels and instruction sheet. The HRU
replacement procedure is as follows:
• On the enclosure, remove the R-clip and pull the cover slowly off.
• Remove the EPIRB and stow it in a dry place. It will activate if wet.
• Hold down the lever arm to take up the force of the spring.
• Push the HRU back then upwards out of the slot in the lever arm.
• When the rear clip disengages slowly release the lever arm.
• The HRU with its breakable rod can now be lifted free and replaced.
• Using pliers, remove the rear E-clip and slide off the old HRU.
• Fit the new HRU over the new rod, with its label facing outward.
• Refit the washer and the rear E-clip. Ensure rod moves freely.
• Mark the HRU with an expiry date 2 years into the future.
• Slide the HRU into the slot in the lever arm and push lever arm down.
• Engage rear washer into backplate by pushing back and sliding down.
• Look under the spring and check that the washer is fully engaged.
• Fit the EPIRB as shown in 5.8.2.
• Refit cover by engaging hole over rod and then snapping into place.
Check that the cover is correctly fitted.
• Refit R-clip through top of rod.
• On side of cover, remove old HRU expiry date and mark new date.
1
2
Breakable rod
HRU
Lever arm
Spring
Engage
washer here
Rear E-clip
Fitting HRU
Washer