# What would cause AC "manual reset" to trip on gen power?



## FlyFisher (Jun 30, 2018)

Attached are a few pictures of my portable AC. We tried to run it this past weekend camping and had a bunch of trouble keeping it going. The "manual reset" would trip consistently about every 15 minutes. It didn't matter what generator, ground rods or not, same thing.

Voltage under load with the compressor running was 123v on both generators (measured at the AC units' power plug, not the generator end). Amperage was 7-8 running, around .5-1a when manual reset tripped and kicked compressor off.

In bouncing ideas off a friend of mine the two theories at the moment are:
1. Back pressure in the vent hose. For the hose to reach the vent port in the tent I had to extend it all the way. With the long hose and bends maybe there was enough restriction to cause enough of a load on the blower fan to cause the "manual reset" to trip? Though, where this theory goes south is the only thing that shuts off with the manual reset tripping is the compressor. The fans all still run - it just stops pushing out cold air.

2. Temperature. It was hot - 90's during the day, though the tent was mostly shaded by a large tarp (mostly for that reason - to get the sun to beat on the tarp and not the tent - keep the oven affect off the tent walls/roof and enough air space between the tarp and tent to decrease the tarp's oven affect on the tent). If the "manual reset" is tripping in an over-temp condition that might make some sense. However, getting the temp down is the reason for running the AC in the first place.

Are there any thoughts? Does anyone have experience with taming this type of scenario?

Per the info sticker by the "manual reset switch" it says "Push it after having removed cause of defect". What are the "defects" that will cause it to trip?? Is it possible to create a less-trippy bypass to get around the causes of the tripping, while still offering protection against things like over-current? The frequency of the tripping was almost like the problems a lot of people have had with GFCI's - only this manual reset was only killing power to the compressor, not the whole unit.


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## JJ Ranch (Apr 23, 2021)

Can you recreate/test the exact situation at your home on utility power?


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## FlyFisher (Jun 30, 2018)

JJ Ranch said:


> Can you recreate/test the exact situation at your home on utility power?


So far no.

I did a test run of the big gen (15kw) a while back and it ran both the whole house AC and this one together.

This unit runs daily on commercial power, no problems.

Edit - I reread what you posted. I could try setting everything up here and test the conditions on commercial power. I suppose if it is reliable daily but the tent config throws it off then its something with the 2 theories - either a venting issue or a temperature issue. 

I have tested the AC on the little inverter gen (EU2200) at the house and it runs. However, I did not run it long enough to reach that 15min mark where it was tripping the reset this weekend. I can try that also. The testing I did was prior to taking the set up out camping a couple weeks ago as a test run - to see if the AC would start and run on the little gen and it does.

What is really weird about it is if there is enough power to start the compressor and get it going then there is plenty of power for it to run - and the voltage shows that at 123v under load.


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## drmerdp (Apr 10, 2018)

Is the red button a circuit breaker, or a control board reset for operating errors?


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## JohnNY (Apr 27, 2020)

If its shutting down the compressor on the A/C the unit is detecting fluctuations or not enough power and protecting itself. It probably has too many starting amps to kick it on or the Starting capacitor on the compressor is going bad. Also are you running all those adaptor cords in the camp? That little homemade pig tail looks like too small gauge of wire in that pic.
Also are you running it on that honda 2200? 

Sent from my moto z4 using Tapatalk


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## FlyFisher (Jun 30, 2018)

drmerdp said:


> Is the red button a circuit breaker, or a control board reset for operating errors?


Good question. It is described as a "manual reset switch". What you see in the info sticker in the picture is what I know about it.


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## FlyFisher (Jun 30, 2018)

JohnNY said:


> If its shutting down the compressor on the A/C the unit is detecting fluctuations or not enough power and protecting itself. It probably has too many starting amps to kick it on or the Starting capacitor on the compressor is going bad. Also are you running all those adaptor cords in the camp? That little homemade pig tail looks like too small gauge of wire in that pic.
> Also are you running it on that honda 2200?
> 
> Sent from my moto z4 using Tapatalk


Going back to the voltage measurement - the running voltage was measured at the power cord of the AC, not at the generator end - which was 123 volts. That is the same number on both generators, as ironic as it is - both being a 15kw starting/13.5kw running rotary and a 2200w starting/1800w running inverter. As to start up voltage drop - not sure. However, the compressor would start and run for some time pushing cold air until about the 15 minute mark.

That having been said - the set up was the generators were about 140-ish feet out of camp to keep the noise down. The gray cable you see is 6 gauge SER cable (aluminum). I have adapters to go between 14-50's, L14-30's, and 5-20's. The 5-20 to L14-30 (yellow cable plugged in to the EU2200) is 12 gauge and feeds both hots of the L14-30. 

At the other end is a break-out box I made that steps down from 14-50 to L14-30 to 3x outlet gangs - one set combo 6-15/6-20's (240v), 2 sets (one each L1/L2) combo 5-15/5-20's.

With the combination I can do exactly as in the picture - when running 120v only I can feed the 1 heavy cable with any generator and have power on all 120v outlets on the other end (both L1 and L2 even on a 120v-only generator). 

Going back to the cable length - yes that is a long way, however with the heavy cable the voltage still measured fine with the loads I had. If I was trying to run the whole house off the 15kw with the same cable length, for example, I would think the voltage would sag more with the heavier combined loads. We didn't even hit 15 amps, thinking of heaviest load all weekend, with a coffee maker and skillet in the morning - the little generator revved up but kept up with it. If we were up around 15 amps draw the overload on the inverter would have kicked it off. I didn't want the little gen screaming hard with that load, though, so we fired up the big one from that point on that particular day. In other words - we weren't taxing the capacity on the cables. The smallest feeder to the break out box is the 12 gauge copper. All the gray cable is 6 gauge aluminum - even the shorter jumpers between L14-30 to 14-50.

If we were taxing the capacity of cables we would see more significant voltage drop.


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## LaSwamp (Mar 16, 2021)

It looks like you have a 9k BTU unit. Something like that is going to pull some juice, especially on startup. It looks pretty old as well. Older a/c units use more power as they age.


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## FlyFisher (Jun 30, 2018)

I got a tidbit from another guy here this evening that said the tripping of the "reset switch" on the AC might be related to head pressure on the compressor. That is another good bit of info, but I haven't wrapped my mind around it. He said running it "outside" (IE - not in a building, though we had it in a tent) might be what is causing the "higher head pressure". I will see what I can find there.


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## FlyFisher (Jun 30, 2018)

Looks like the "manual reset switch" Is a "pressure switch".



















So the next question is what is throwing off the pressure? Doesn't appear to be power related at all.

On the up side - it doesn't look too hard to bypass the switch. The question there is what is the risk of damage to the compressor doing so?

The AC is back in service here running perfect. No issues with it starting up and continuing to run. Thermostat is normal.


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## drmerdp (Apr 10, 2018)

It might be be a discharge line high limit switch. I looked up the model AC and the trouble shooting page refers to resetting the switch in the event of a blocked or restricted exhaust hose.


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## JohnNY (Apr 27, 2020)

The problem is the lengthened exhaust hose. The fan can only push air so far before the back pressure prevents sufficient movement. Like a pump is rated in water column pressure. The fan cannot exhaust the heat from the condenser sufficiently enough therefore the freon pressure rises to the point it is tripping the safety because it cannot turn the vapor into a liquid again. 
Put the unit right next to where it is to exhaust the heat out the side of the tent

Sent from my moto z4 using Tapatalk


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## FlyFisher (Jun 30, 2018)

JohnNY said:


> The problem is the lengthened exhaust hose. The fan can only push air so far before the back pressure prevents sufficient movement. Like a pump is rated in water column pressure. The fan cannot exhaust the heat from the condenser sufficiently enough therefore the freon pressure rises to the point it is tripping the safety because it cannot turn the vapor into a liquid again.
> Put the unit right next to where it is to exhaust the heat out the side of the tent
> 
> Sent from my moto z4 using Tapatalk


This is the "manual reset switch". It is, in fact, a pressure switch. So I am interpreting what you wrote to be exactly whats going on - freon pressure rise due to temp. 



















The hard part of the set up is there isn't anywhere for the AC to move to.

What I could try is to put a helper fan in the exhaust line to take the pressure off the venting, maybe even add vacuum to it to help it.


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## JohnNY (Apr 27, 2020)

FlyFisher said:


> This is the "manual reset switch". It is, in fact, a pressure switch. So I am interpreting what you wrote to be exactly whats going on - freon pressure rise due to temp.
> 
> View attachment 9624
> 
> ...


That would help if you put an inline duct fan that would pull the exhaust right where it is to exit the tent. If you give that a try let us know if it worked.


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