Max Machinery 289 Series Flow Meter Transmitters - Manual (Page 5)

289-760-350 © 1987 (Rev 5/06) Max Machinery, Inc. ( 4 )
Installation
Mounting: The Model 289 transmitter screws on and off of the flow meter. Because of the
random location of the starting point of the threads, one transmitter will probably not line up
with the "in" and "out" ports of the flow meter like another will. The electrical outlet of the
transmitter can be rotated one turn by loosening the clamping screw. (See drawing, page 2)
Moisture Protection: The electrical circuitry of the weather-tight, explosion proof transmitter
is enclosed in a liquid and vapor tight enclosure. All joints are sealed by welding or by "O"-
rings. If this sealed condition is to be maintained, the conduit connection to the enclosure
should be made liquid and vapor tight by using pipe dope or a potting fitting (U.L. requires a
potting fitting within 18" of the transmitter.). If a transmitter is located outside and this
precaution is not taken, moisture may form inside the housing. This will cause the circuitry to
give an inaccurate output or possibly no output at all. In the long run it will cause corrosion
and failure. The amphenol connector versions of the 289 Series Transmitter offer moderate
protection from moisture and dust but are not totally sealed.
Temperature Considerations: High ambient temperatures (120°F/50°C) should be avoided if
possible. It is a good idea to locate the transmitter away from hot spots such as steam pipes,
ovens and heaters. The electronics of the 289 Series Transmitters are rated for operation up to
65°C or 150°F. Because some heat travels from the flow meter to the transmitter
electrical enclosure, the temperature the electronics see is a function of both the ambient
and the flow meter temperature. The graph below shows the relationship between the
maximum ambient transmitter temperature and the fluid temperature through the flow meter.
The pickup coil of the 289 Series Transmitter is insulated with an epoxy that is rated to
232°C/450°F. This is the maximum flow meter fluid temperature.