Not a good idea to use this to run AC?

[JPin AZ]

I have done it before with my old TT. It was hot today so I thought I would try the AC in my new 2011 ROO 23ss while working inside. AC blew cold until I turned it off. It did not want to restart. After sitting it did restart but I did not run it because I was afraid I was going to kill it. Thoughts?

[dieselbobcat]

High head pressure. Might have been off on limit... there is also a timer to prevent short cycling.

What were the ambient conditions?
What was the duration between shutting it off and you trying to restart it?

[JPin AZ]

94 Degrees ran it for 30 plus minutes. Restart almost immediately.

[dward51]

Probably still had pressure in the compressor when it tried to kick back on. They can start pretty much every time when it's been sitting as there is less pressure built up in the compressor. On the lower amperage line, it did not have enough "umph" to kick over the compressor at the initial surge. I would not do that much as you can damage the compressor.


If you are going to run one like that, I would make sure to start it with the thermostat set high enough so the fan comes on first then lower the setting so the compressor kicks on. If the fan and compressor both kick on at the same time, it draws more amps. If you can manually set your fan to on, it may restart on yours. But it's better to use a proper amperage outlet (also if you have a 20 amp available instead of 15 it would be better than the 15 in the photo above).

[JPin AZ]

Thanks for the quick replies. I have only ran the AC a couple of times plugged into the house. I thought I would be okay using the heavy TT cable. I will not do this again. Years ago i knocked 220v in this box down to 110. I might have to research if I can add 30 amp using the unused wiring in the box.

[JPin AZ]

We have a local trip planned next weekend it sounds like my AC will be fine plugged into 30 amp.

[wmtire]

Originally Posted by JPin AZ

Thanks for the quick replies. I have only ran the AC a couple of times plugged into the house. I thought I would be okay using the heavy TT cable. I will not do this again. Years ago i knocked 220v in this box down to 110. I might have to research if I can add 30 amp using the unused wiring in the box.

I don't imagine you even have 15 amps available to the RV as I can see other items plugged in beside the outlet your RV is plugged into.


Mark Polk has a good article on this:


Basic RV Electricity - RV Information (RV Maintenance)

[JPin AZ]

True, cordless drill charger not being used and boom box that was running.

[JPin AZ]

I guess the question is does a breaker limit amps before tripping?

[formerFR]

a breaker is a 'heat' sensitive device, and there's no way for it to in any way 'limit' anything until it trips from 'overheating', which is it's design.

using a 15a or 20a outlet is perfectly fine for powering a 13.5 or so air conditioner, as it draws 12-13 amps even at full bore.
if it worked for a while, then you've proved the point.

why didn't it restart?
well, you said it blew cold... so maybe it just froze up, right as you initially turned it off, which requires sometimes a long wait before it will power back up.

your adapter, the 30a to 15a block adapter, simply allows you to plug into a 15a outlet, that's all... otherwise there's no difference from plugging the air conditioner into the 15a outlet directly... it's a maximum of 15amps.

[Iwannacamp]

You said you ran the a/c inside? In a garage? May have limited the air flow and caused high/excessive head pressure. This could/would have increased amperage and possibly causing the compressor to thermal out. If this was the case leave off at least an hour. Correct the air flow problem and chill on.

If I read between the lines...you turned off and quickly back on? These aren’t super strong compressor motors and would struggle to start under high load.
Most digital stats have a short cycle/restart delay...prolly not crappy RV stats.

It could easily be a weak connection/low voltage/inferior wiring. Only way to know is monitor volts and amps.

I personally think the addition of a start capacitor/potential relay(hard start kit) to these mobile a/c units to be a great benefit. This would help with most starting problems. Yes I know not all compressors are supposed to have a “hard start kit installed”. I personally would not fear this. Ymmv

[JPin AZ]

Okay, my fear was I ran it low on amps. This did not happen because it ran. If it needed more amps than the circuit could handle it would have tripped the breaker. I am comfortable thinking these units are slow to equalize and I simply had to much high side pressure for the unit to restart so quickly. It is working as designed. thank you.

[JPin AZ]

I will make sure that the roof top fan is running and the coils are clean.

[NJKris]

I am comfortable thinking these units are slow to equalize and I simply had to much high side pressure for the unit to restart so quickly. It is working as designed. thank you.

That would be my guess. My unit has a high pressure limit switch that supposedly keeps it from restarting right away if you cycle it, or it has a power drop out, to prevent damage. If you don't have this switch, it can be unhealthy for your unit if not kill it.

[dward51]

Yes, it will draw more amperage on compressor startup than just running. Look for the "locked rotor amp" rating in your manual (or download the specs of your AC unit). That is what it can possibly draw, but it is only for a second or so. It's not long enough to trip a thermal breaker into overload. But if you are on a 15amp circuit with 14 gauge wiring, it will not deliver that kick the compressor needs to overcome any residual pressure in the system. Doing this over and over can possibly damage the compressor.

For a 30amp line, you will need to use 10 gauge wire in addition to the breaker and proper outlet, etc... Modern 10 gauge will normally have an orange jacket.

[JPin AZ]

For a 30amp line, you will need to use 10 gauge wire in addition to the breaker and proper outlet, etc... Modern 10 gauge will normally have an orange jacket.[/QUOTE]

Good to know, thanks.