Generator running two AC units, outlet appliances get hot

As others have said, you should be OK at 118 volts. If you have a microwave with a digital clock, start the generator, set the clock, and check how close it is to your watch, or clock for 10 minutes. If it is running fast or slow, load the generator with an AC and check again. If it is within a minute or two, your hertz are close enough to not cause problems.

I don't think you have any thing to worry about with your generator. Just change the oil and fuel filter and you should be good to go. As long as it maintains 118 volts under load it is fine. Depending on your volt meter, the accuracy might be between .2% and 5%. Even a high quality .2% accuracy meter is 2.4 volts AC.

You do definately need to have someone who is knowledgeable and has the right test equipment (good multimeter) and knows how to use it. That may be you, but probably not.

The risk to you is that if the controller is malfuctioning it could cause voltage problems that will damage the various electrical items in the coach. If that happens, it will be much more expensive than having the generator looked at/repaired by a knowledgeable person.

As a "do it myself" person, the most important thing is to know when I do NOT know how to do something. Know what you know, and know what you do not know.

Jackie Treehorn wrote:

tropical36 wrote:

wildmanbaker wrote:
You should be all right at 118v. You should not get into trouble until about 110v or less. The voltage went up when you loaded the gen, and the governor called for more power from the engine, more rpms.

I'd say it has more to do with the regulator which may be automatic and yes the engine speed might appear to increase when actually trying to maintain it, but the RPM must stay within limits to produce the 60HZ required frequency, as per the formula....Generator Frequency (f) = Number of revolutions per minute of the engine (N) * Number of magnetic poles (P) / 120

So if I'm reading between the lines, you both would be looking to take this in to a dealer who services Onans(of which I found one close by if that's the route I need to take)?

That will have be your decision, but it doesn't sound like you have any serious problems as yet and cummings/onan is an expensive place to visit for any reason. I mean if I was looking for reasons with my Generac, I'd probably have to junk it, so I ignore a lot, keep adding oil, restarting when necessary and keep on trucking.

tropical36 wrote:

wildmanbaker wrote:
You should be all right at 118v. You should not get into trouble until about 110v or less. The voltage went up when you loaded the gen, and the governor called for more power from the engine, more rpms.

I'd say it has more to do with the regulator which may be automatic and yes the engine speed might appear to increase when actually trying to maintain it, but the RPM must stay within limits to produce the 60HZ required frequency, as per the formula....Generator Frequency (f) = Number of revolutions per minute of the engine (N) * Number of magnetic poles (P) / 120

So if I'm reading between the lines, you both would be looking to take this in to a dealer who services Onans(of which I found one close by if that's the route I need to take)?

wildmanbaker wrote:
You should be all right at 118v. You should not get into trouble until about 110v or less. The voltage went up when you loaded the gen, and the governor called for more power from the engine, more rpms.

I'd say it has more to do with the regulator which may be automatic and yes the engine speed might appear to increase when actually trying to maintain it, but the RPM must stay within limits to produce the 60HZ required frequency, as per the formula....Generator Frequency (f) = Number of revolutions per minute of the engine (N) * Number of magnetic poles (P) / 120

You should be all right at 118v. You should not get into trouble until about 110v or less. The voltage went up when you loaded the gen, and the governor called for more power from the engine, more rpms.

tropical36 wrote:

I'm heading to the Onan website to see if there is an adjustment I can make to bring that voltage down towards 110. It will also be a good time to find out how many hours I should be running it between servicing it-

I like about 125vac at no load so I can hope to maintain a reasonable level when at full load. I think 120v is optimum and hopefully it never drops below 115v, but that's just wishful thinking in a lot of cases.
With some if not all generac gensets, there's a LED on the voltage regulator board, along with the adjustment screw and I drilled a hole in the cover so that I can see it, as it doesn't always have an output and requires restarting. Just saying, in case you feel the need to see this light as well.

That's interesting- no load I'm at 116 to 117 volts at each outlet but once loaded with one or both AC units the voltage goes up to 118. You're saying you wouldn't think the source of the heat for devices using the outlets is the 118 volts?

I'm heading to the Onan website to see if there is an adjustment I can make to bring that voltage down towards 110. It will also be a good time to find out how many hours I should be running it between servicing it-

I like about 125vac at no load so I can hope to maintain a reasonable level when at full load. I think 120v is optimum and hopefully it never drops below 115v, but that's just wishful thinking in a lot of cases.
With some if not all generac gensets, there's a LED on the voltage regulator board, along with the adjustment screw and I drilled a hole in the cover so that I can see it, as it doesn't always have an output and requires restarting. Just saying, in case you feel the need to see this light as well.

chuckftboy wrote:
Jersey, the a/c units are sealed systems and unless the PO had fittings installed, there isn't any way to add refrigerant. The original charge was weighed in by ounces, not charged by pressures but you might get close if you have pressure taps.

What's the sweet spot on it if I can't do it myself? We have Camping Worlds that are both about an hour from us but they seem to have a seriously high turnover of mechanical staff and with any other option, we'd take it. I presume there are other businesses who can service the AC units?