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My Onan MDKAV uses 309-0295-01,
the part that is in Eric's photo.
Sabbatical III, SM#419, Rhode
On 7/29/2020 10:05 AM, CW Bill Rouse
WAIT and read this before you
Not all Onan Generators in all SMs and 54s
are created equally. Use your ohmmeter to check for
continuity between the terminals on the temperature sensor
on the exhaust elbow. Some Onan models have part 309-0295-01
which is Normally Closed. Other models have part 309-0295 is
Normally Open. Which sensor you have depends on your
Onan Model and Serial. Check the parts manual for your
model to determine how to test this sensor. Or call your
Cummins/Onan dealer with your model and serial number.
Good to know: The normal temperature of
the exhaust elbow is
about 50C and the normal temperature of the coolant is about
80C. Were these in range? How many
hours since the last impeller change? Should be less than
300hrs or 12 months. The impeller blades can look OK, but the
impeller can be defective. You
can have some water flow, but not enough to keep the elbow
below about 70C (the approximate cut-off temp).
Also, remember there are a number of sensors
in the shutdown system, and these switches will fail. I
exhaust manifold temperature switch and the water-flow switch because
of an accumulation of debris inside. I also had one situation with a
loose connection on a switch. Did you use your laser temperature gun to
I will order one. I have never had an issue with mine
but you never know. Thanks for doing this.
Sabbatical III, Sm#419, Rhode Island, USA
These are simple thermal switches. They are normally
If the circuit opens up the genset stops.
My problem is sometimes they burn out and other times
I hit the switch and it separates.
On July 28, 2020 at 10:41 PM
"Mike Longcor (SV Trilogy)" <svtrilogy53@...>
Thanks Eric. Sent you a message
with order details.
When these fail, go bad, or
break, how do you know? Does it prevent the
genset from starting/running? Or does it allow
the genset to overheat if there are issues with
the cooling system (broken impeller for example)
and potentially damage things?
SV Trilogy SM23