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GStream40
06-08-2008, 10:16 PM
We have a Onan 7.5kw QD (Quiet Diesel) generator that has always ran perfectly until today.

We were traveling and it was running great and generating the electric current to run both our air conditions for appox. 45 minutes when all of a sudden it shut down. The light on the button was flashing 3 times in a cycle indicating that it needed service.

I checked the oil and coolant at the next stop and they were okay. I checked the circuit breaker on the generator and it was okay.

I started the genset up again and the engine runs fine, BUT it does not put out and 110 volt current.

I checked all the breakers in the coach and I cannot figure out what is wrong.

Any experts out there or maybe someone has had this problem that could give some clues at what to check??

It is no longer flashing any codes.

Thanks, Ron

djqualls
06-09-2008, 01:33 AM
Ron,

Did you put a meter at the genset?

Have you opened the transfer switch and checked that for voltage?

Did you cycle the main breaker at the Genset?

Only thing I can think of at the moment.

Good Luck.

Dave......

RJ82much
06-09-2008, 11:47 AM
Your generator will shut down when your fuel tank reaches something like 1/4 to 1/3 tank.

There is a likelyhood that the breakers at the generator have tripped if you were using the AC units. Hint for this: turn the thermostat fan control to "manual" so that fan is on all the time. Give it a couple seconds before turning on the AC. The AC will cycle on & off but not the fan. This greatly reduces the current surge that often trips the generator breaker.

Let us know what you discover

GStream40
06-09-2008, 09:57 PM
Dave,
I checked the main breaker at the genset and cycled it, didn't help.

I have to put a meter at the genset and check it for voltage as soon as the outside temp cools down, it has been around 90 the last couple of days, way too hot for me to be messing around.

RJ,
We have 3/4 tank of fuel. The genset engine runs fine, just no 110 volt.
The breakers on the outside of the unit didn't trip.

Thanks for the hints, will follow up on them.

Ron

rdlamb
06-10-2008, 12:29 AM
Ron:
Do you have 1 or 2 breakers on the generator?

Mine has a 37 amp x 2 single breaker. It went out. As explained to me via Cummins/Onan the breaker sends out 2 lines, capable of 37 amps each. When you run 2 A/C(s) you may exceed the 37 amp load of one line as the start up of both A/C(s) draw a lot of amps.

The switch blew one line. The generator would run fine, but no 110 output.
I checked the transfer switch (under your bed), and no 110 in from the generator. Fixing a generator was out of my league, so a service call ensued.

Onan replaced the switch with a "newer" or "improved" switch, and everything seems to be running well.

Always seems to happen when it gets hot outside. Mine went out during the 8 weeks of 100 deg + weather that cooked San Antonio last spring.

GStream40
06-11-2008, 07:26 AM
Well yesterday afternoon I started checking things out.
Started with checking the genset wiring at the junction box that is mounted on the firewall behind the "hood" on the front of the coach.

To my surprise the genset was putting out 122 volts on both legs, well within range.

So I went to the transfer switch that is located under the cedar chest at the foot of the bed. I had 122 volts coming into the switch at the generator teminals, but nothing to the output side of the transfer switch.

The switch is a Iota Engineering Co. model ITS-50R Automatic Transfer Switch. Checked their website and downloaded the wiring and manual for this switch.

Read the information they had listed for the Time Delay Module that is built into the unit and how to flip the switch to test if this part is bad since the LED on the module was not lighting up as it should be. I flipped the switch and started the genset hoping that the Transfer switch would operate as was indicated in the instructions if the module was bad.

Nothing, zero, So the switch must have more serious problems.

I found a website for Solar Sellers and they sell the Iota ITS-50R Auto Transfer Switch for $115.00 plus shipping of $16.00.

So I will call them this morning to see if they have it in stock and can ship it right away.

Maybe I can have it by this weekend and get it installed. We are going to leave on the 21st for a week long Gulf Streamers Back Home Rally and we will need the roof airs while traveling, especially if the temperatures get up to 90 like it has been last weekend.

If after I receive the new one and if I am able to repair the old one, then I will keep it for a spare just in case it is needed.

Thanks to everyone for their guidance and input to my problem, it was much appreciated.

Ron

rdlamb
06-11-2008, 08:51 AM
Bravo Ron, and thanks for the detailed recipe on how to test your system when the generator does not provide power to the coach.

GStream40
06-11-2008, 12:17 PM
Bravo Ron, and thanks for the detailed recipe on how to test your system when the generator does not provide power to the coach.

Well actually if I was to do it over again, I would start at the transfer switch to see if there was voltage there. It would save some time of opening the junction box and bearing/retapeing the wiring connections for the tester to make contact with the probes.

Ron

GStream40
06-14-2008, 07:07 PM
WOW, talk about great and fast service, I order the new transfer switch on Weds. and it was delivered in Friday's mail. Great service by the USPS Priority Mail and John Drake Services http://www.solarseller.com/index.htm

I installed the new transfer switch today and everthing works great, genset power was deliver trough the transfer switch and I ran the both air conditioners for about an hour.

After I was all done, I took the old failed transfer switch apart, checked the coils, contracts, and wiring. All checked okay. Then I removed the Time Delay Circuit board and found a small burnt hole with black around it in the bottom of the circuit board. Hmmmm

Guess I found the failed part. I just ordered a new circuit board from Solar Sellers, John Drake Services for $16.00. I will install it and the test the transfer switch, if all is well then I will have a working spare just in case it is ever needed again.

All is well... :lol:

Ron

neondon
05-22-2018, 08:23 PM
Thanks all for the tips for this still-learning "master." I'll check under the bed for the transfer switch power and delay components before I start removing wheels, engines, etc. ...