Kohler 7.5 issues

[James McDowell]

I just replaced the front ac unit on my coach. Went from a 11,500 BTU to a 15,000 BTU. I haven't had the coach that long but I did notice that the old Kohler gold 7.5KW would trip even the old ac unit after running for about 40 or so minutes. I assume something is tripped but I don't have to manually reset a breaker. After a few minutes the genny starts up again but this time it only runs about 5 minutes and trips again. The new unit does the same. The ac runs fine indefinitely on shore power. I checked the voltage under load per the meters on the kitchen panel and the one leg that the front ac is on dips to about 106 volts. I haven't checked RPMs on the genset and I don't know if the cycles are at 60 hz or not. I'll be the first to admit that my electrical skills are somewhat remedial so please keep the replies at my skill level. Like most FCs, I don't have dash air anymore and rely on the front ac for keeping cool on the road. Thanks for the help.

[birds_first]

Someone will come to your rescue, but to me it sounds like you may have one of those resettable 12v breakers in the overhead compartment going bad. The 12V AC switch next to the driver's seat is not getting power to keep the 120V power relay open to the front AC unit. When it warms up the 12V breaker expands causing it to trip, once it cools down the 12V breaker resets itself. Just a thought.

[James McDowell]

Thanks John. My coach is a Wanderlodge II and there is no switch for the air conditioner next to the driver seat. You have to turn on at the air conditioner itself. Not sure what you mean by the beakers in the power centers in the overheads. My understanding is they are all 12 volt and my issue is 110v AC tripping the air conditioner while powered up by the Kohler genny.

[birds_first]

Originally Posted by James McDowell

Thanks John. My coach is a Wanderlodge II and there is no switch for the air conditioner next to the driver seat. You have to turn on at the air conditioner itself. Not sure what you mean by the beakers in the power centers in the overheads. My understanding is they are all 12 volt and my issue is 110v AC tripping the air conditioner while powered up by the Kohler genny.

Then you don't have a problem No on my 88 and others the AC power-on switches are on the overhead above the driver, other models they are down on the left side of the driver, for those who do have them they are a 12V switch, with a 12V resettable breaker, that controls a relay for the 120 power for the AC units, no 12V no 120V. Purpose of thes 12V switches so the driver don't have to stop the bus to get up and turn on the AC units, that task can be done from the driver's seat. Sounds like you may have other issues, does your rear AC work? On some birds with the 12V switches they also control the electric heaters.

[GEEZER]

Maybe you should be looking for a loose wire or wires somewhere in the circuit to that a/c from the genny. Maybe a bad breaker in the disconnect by the genny or switch for shore or genny power if it runs ok from shore power.

[Chap]

Originally Posted by James McDowell

I just replaced the front ac unit on my coach. Went from a 11,500 BTU to a 15,000 BTU. I haven't had the coach that long but I did notice that the old Kohler gold 7.5KW would trip even the old ac unit after running for about 40 or so minutes. I assume something is tripped but I don't have to manually reset a breaker. After a few minutes the genny starts up again but this time it only runs about 5 minutes and trips again. The new unit does the same. The ac runs fine indefinitely on shore power. I checked the voltage under load per the meters on the kitchen panel and the one leg that the front ac is on dips to about 106 volts. I haven't checked RPMs on the genset and I don't know if the cycles are at 60 hz or not. I'll be the first to admit that my electrical skills are somewhat remedial so please keep the replies at my skill level. Like most FCs, I don't have dash air anymore and rely on the front ac for keeping cool on the road. Thanks for the help.

Jim, Are you saying the generator shuts down and then can be restarted after a few minutes?

[birds_first]

If your not getting power from the genny to the air conditionor unit you could have a sloppy breaker on that leg of power from the genny. Do you have a breaker control box off the genny? If so check those breakers. When on shore power you're getting power directly that does not go through that genny power control breaker box. You should have maybe 2- 30/35 amp house breakers one for each leg on the genny power breaker box. Just a thought.

[Bill Pape]

Originally Posted by James McDowell

I just replaced the front ac unit on my coach. Went from a 11,500 BTU to a 15,000 BTU. I haven't had the coach that long but I did notice that the old Kohler gold 7.5KW would trip even the old ac unit after running for about 40 or so minutes. I assume something is tripped but I don't have to manually reset a breaker. After a few minutes the genny starts up again but this time it only runs about 5 minutes and trips again. The new unit does the same. The ac runs fine indefinitely on shore power. I checked the voltage under load per the meters on the kitchen panel and the one leg that the front ac is on dips to about 106 volts. I haven't checked RPMs on the genset and I don't know if the cycles are at 60 hz or not. I'll be the first to admit that my electrical skills are somewhat remedial so please keep the replies at my skill level. Like most FCs, I don't have dash air anymore and rely on the front ac for keeping cool on the road. Thanks for the help.

A 7.5K Watt generator will handle the air conditioner.
We need to know what is tripping the AC voltage or is the generator shutting down from overheating or some other reason. I am a little confused to help further.

[James McDowell]

Sorry if I didn't provide enough info. The issue occurs when I'm running down the road with the genny running and the front ac unit on. It'll run fine for about 40 or so minutes and then the ac stops and the indicator light on the genny start rocker panel by the steering wheel goes out. Since I'm running down the road I'm not sure if the genny motor has stopped or the generator head has just stopped producing electricity. I shut the switch down and can restart a few minutes later but it will only run a few minutes before the process repeats itself. I don't think the genny motor shuts down or overheats ( it's belt/fan cooled). What's wired is that I don't have to reset a breaker to restart. Is 106 volts sufficient for a 15,000 BTU ac unit? The little four banger seems to run smooth without any hunting......nice steady RPMs but I'm not sure it's 1,800 or not. Thanks for helping.

[Bill Pape]

I think Ya need a co-pilot, need to know if the genie shuts down & check the coolant temp.
Also check the coolant level & the oil level.