No Air Con when using generator

[chpsk8]

Hello.
My new to me 95 355 Aft Cabin has air and a generator. During the survey and a couple other times I was on the boat we had AC and the generator running while out on the water. The previous owner isn't around this week so I can't ask.

Here's my issue...
I had the AC running, then went to leave the slip. I disconnected the shore power lines, went in and started the generator without changing anything on the panel. Neither AC unit powered up after that. No lights on the AC control panels at all.
I flipped every configuration of switches I could think of with no joy. I see amps and volts on the shore power 1 meter. Nothing on shore power 2. AC is tied to shore power 2 when plugged in.

When we got back to the slip I plugged into shore power and the AC kicked right on like nothing happened.

Genny is a Kohler if that helps. I'm thinking I'm just missing something simple, but I can't figure it out.

Thanks for the help .

[bud37]

Have you tried the breaker on the generator......there is one on the box there, throw it off and then on then start the gen.......this would only apply if there was no power to either side of the AC power, if you have it on one side there has been a recent thread about just that , pics and all, maybe a quick search, if I remember right there is a fair bit of good info on it........good luck man....

[Viper]

Pretty sure some 355s have source relays. When you turn the generator on, does the source voltage switch automatically to generator power or do you have to switch a breaker from shore to the generator position? If you don't have to, then there is an auto transfer relay likely behind the breaker panel who's one side has failed or there is a poor connection at the #2 source terminals.

[km1125]

If this has the automatic switching relays, then it sounds like one of your relays is bad. Someone else on here had a very similar issue not too long ago.

IIRC, The relays are in a box behind the electrical panel. Be careful to make sure the circuits are dead before you go poking around in there, especially because you have two sources (shore and genset) and two different circuits ("1" and "2" or "A" and "B"). SAFETY FIRST!

[chpsk8]

Thanks for the leads. I have power on shore 1 when the gen is running, but no power on shore 2. When we did the sea trial we went from shore power to generator with no flipping of switches.
I'll wait for the family to take a long walk and then kill all the power and start with just tightening connections. If that does'nt work I'll swap the two relays and see if I can move the problem so shore 1 doesn't have power.
First though, I need to figure out where that thread is so I can see some pictures!

[km1125]

Here ya go... it was under "auto transfer switch" (and there are pictures!):

viewtopic.php?f=12&t=3336&p=22518&hilit=transfer#p22518

[chpsk8]

QR_BBPOST Here ya go... it was under "auto transfer switch" (and there are pictures!):

viewtopic.php?f=12&t=3336&p=22518&hilit=transfer#p22518

Thanks for the lead! I fixed it.. here's my synopsis.

Thanks to this thread I was able to track down the auto switching relay. It was in my electrical panel at the top behind the volt/amp gauges.

When I took the panel apart there were two burned out wires. I believe they shorted due to an issue with the shore power cable not being tightly connected and shorting out at some point. I went to West Marine and bought some 600v cable and replaced those wires and at the same time replaced the auto relay using the Amazon link referenced earlier.
The part was called "NTE Electronics R04-11A30-120 Series R4 General Purpose Multicontact AC Open Frame Relay, Heavy Duty, DPDT Contact Arrangement, 30 Amp, 120 VAC"
It was a perfect match. I killed all power to the boat including the 12v sources. Checked the panel for voltage and then dove in and swapped out the part. Pretty simple to do. Just change one wire at a time and work clockwise around the relay until everything is done. I tied back a couple stray wires just to make it a little neater in there.

Thought I would loop back on this just in case anyone else has the same issue and just add my experience.

[km1125]

Thanks for closing the loop! It's always nice to hear when someone resolves the problem that was reported!!

[Viper]

Thanks for the follow up and glad you got it working.