Changing The Valve Assembly; Warning; St40 Speed Transducer Spare Parts List - Raymarine ST40 Service Manual

4. Tap the new shaft (1) into place until it is flush with the housing, ensuring that the

Changing the valve assembly

The transducer incorporates a self-sealing valve which minimizes the flow of water
into the vessel if the insert assembly is removed. When the insert assembly is
removed, the curved vane is activated by a spring and by water pressure, which push
the vane upward to seal the opening. The valve assembly is held in place with a
corrosion resistant snap ring.

WARNING:

Do NOT attempt to remove the self-sealing valve assembly when the vessel is in
the water, as the consequent inflow of water may cause the vessel to sink.
If the valve mechanism fails, ensure the vessel is not in the water, refer to the ST40
Speed transducer illustration, and carry out the following:
1. Remove the snap ring (5), using a screwdriver to pry the end of the ring free.
2. Slide the valve assembly upward, out of the housing.
Note: The vane retainer pin is a loose slip-fit and may slide out when the assembly is
removed from the housing.
3. To install a valve assembly, insert it into the housing (vane tongue pointing

ST40 Speed transducer spare parts list

The item numbers refer to the ST40 Speed transducer illustration.
Item
1
2
3
4
5
6
3 - 2
IMPORTANT: Ensure that the flat surface of the paddlewheel blades face the
direction of the arrow on top of the insert assembly.
When the insert assembly is installed in the housing, the arrow on the top insert
cap and the water exposed flat surface of the housing should both face the front of
the vessel.
shaft enters the centre hole of the paddlewheel bearing. Failure to align the
bearing before inserting the shaft can result in bearing damage.
downward). Install the snap ring (5), making certain that it locks into its groove in
the housing wall.
Spare/Accessory Description
Speed transducer service kit
comprising:
Paddlewheel shaft
Paddlewheel
'O' ring (x2)
'O' ring (x2)
Snap ring
Valve assembly
Part 3 Transducer Servicing
Part No. Comments
D234
ST40 Instruments Service Manual 83149-2