Front AC tripping transfer switch

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Front AC tripping transfer switch

June 05, 2023, 11:20:45 am

Good morning,

I recently posted about the issues I've been having with my transfer switch switching on and off.
It seems as if it had something to do with the shore power reel since sometimes I would move it, and the power will come back on, and sometimes it wouldn't.

Couple of nights ago when the front AC tried to start the transfer switch started going back-and-forth about five times before I shut the front AC off. It was 0200.

I thought maybe it had something to do with the capacitors on the front AC, which are both original from 2002.

Today I changed both capacitors on the front AC. When I turned the unit on the same thing happened again, the transfer switch started going back-and-forth..

Keep in mind that the rear AC was not running at the time. This phenomenon only happens with the front AC. The rear AC causes no problems and this is the only unit I've used in the last two days.

Are there any other things I can do to resolve this problem?

I was going to go and buy a male 50 amp plug to attach and bypass the shore power reel but don't know if that would fix it since the rear AC doesn't cause a problem.

Any suggestions?

Re: Front AC tripping transfer switch

Reply #1 – June 05, 2023, 11:50:32 am

Power reel is not getting a good contact.. Might want to pull it.. Double check connections first but my guess is the rings are pitted and burned on the reel.

Re: Front AC tripping transfer switch

Reply #2 – June 05, 2023, 12:43:45 pm

Quote from: Lt403 – June 05, 2023, 11:20:45 am

I recently posted about the issues I've been having with my transfer switch switching on and off.
It seems as if it had something to do with the shore power reel since sometimes I would move it, and the power will come back on, and sometimes it wouldn't.

Couple of nights ago when the front AC tried to start the transfer switch started going back-and-forth about five times before I shut the front AC off. It was 0200.

I thought maybe it had something to do with the capacitors on the front AC, which are both original from 2002.

Today I changed both capacitors on the front AC. When I turned the unit on the same thing happened again, the transfer switch started going back-and-forth..

Keep in mind that the rear AC was not running at the time. This phenomenon only happens with the front AC. The rear AC causes no problems and this is the only unit I've used in the last two days.

Front AC is on one leg of power, rear AC is on the other leg.

On our former coach, the only things on the leg that the front AC was on were

Front AC (breaker 10)
Engine block heater/one leg of Power Line monitor (breaker 9)
Inverter/charger (breaker 8 )

So make sure your engine block heater is off, and watch the inverter and Power Line monitor readouts when the front AC tries to start.

Re: Front AC tripping transfer switch

Reply #3 – June 05, 2023, 01:23:46 pm

NevadabornRv,
That will probably be my next step to disconnect the reel, add a male and use an extension.

Michelle
I see the engine heater but I don't think I have one since I have the Aquahot. Right?

I got the front AC working, transfer switch cycled 2 times then stopped and front AC has been running at least 30 min. Rear AC was turned off.
Line voltages 124 each leg.

Turned on rear AC with front AC actually running and no issues. Line voltages now 123,122.

Not sure if I needed to do anything (charging)to both capacitors before installing them.

Re: Front AC tripping transfer switch

Reply #4 – June 05, 2023, 01:34:19 pm

I have the block heater and the aquahot. My switch is under the bed... Looks like a light switch

Re: Front AC tripping transfer switch

Reply #5 – June 05, 2023, 01:51:36 pm

You are right, I do have one but it's disconnected at the receptacle.
Don't remember if I did that or if the prior owner did.
I always use the Aquahot if needed.

Re: Front AC tripping transfer switch

Reply #6 – June 05, 2023, 02:50:33 pm

Frank,

While you were changing out the capacitors did you see another device on the floor close to the capacitors? It would be mostly black with a couple of wires coming out. If so that is a PTCR or something like that. (long time sense HVAC school) Think of it as a supper boost for the start windings. If it is bad it could cause some of your symptoms.

In some of your statements you have said "it has been running for 30 min" Now for some clarification: Are you sure that the compressor is running and not just the fan motor.

Mike

Re: Front AC tripping transfer switch

Reply #7 – June 05, 2023, 02:51:43 pm

Is this the gen/shore power transfer switch you're talking about or the one under the bed?

If it's the main one, there is a small orange relay which is the under/over voltage cutout. Mine was problematic in the past and would sometimes not engage the transfer switch. I have also had it cycle the transfer switch a few times as well. Might be another place to look.

Re: Front AC tripping transfer switch

Reply #8 – June 05, 2023, 03:14:47 pm

Hi Mike,
I bought both capacitors and the hard start kit came with the PTCR which I also changed out.
The front AC has been running and is producing cold air so I would say the compressor is running. Never had a cooling issue.

I didn't see any bulging or liquid on the capacitors but the corrosion is obvious.
Plus they are from 2002.
I cleaned the connectors with a brass brush before reinstalling.

Re: Front AC tripping transfer switch

Reply #9 – June 05, 2023, 03:25:59 pm

Keith,
That is the xfer switch I'm talking about.
They have mentioned the hi lo potentiometers before but I haven't touched them yet, I see the red dot and the slot but really can't tell how it's read

Re: Front AC tripping transfer switch

Reply #10 – June 05, 2023, 04:10:26 pm

Quote from: Lt403 – June 05, 2023, 03:25:59 pm

Keith,
That is the xfer switch I'm talking about.
They have mentioned the hi lo potentiometers before but I haven't touched them yet, I see the red dot and the slot but really can't tell how it's read

The numbers on the dial are somewhat meaningless. They're set with a known voltage source. Lower should be set around 108 V, upper around 132 V (that's where you need a power supply with a calibrated voltage output.) They are somewhat (well, essentially) moot if you have and use a Progressive EMS wired into shore power that does the same thing (prevents over and under voltage from passing.)

Re: Front AC tripping transfer switch

Reply #11 – June 05, 2023, 05:15:40 pm

I use this at the pedestal which has a voltage range from 102/134v.
During these incidents it has not cut power at the pedestal.

Re: Front AC tripping transfer switch

Reply #12 – June 05, 2023, 05:45:05 pm

It tells you the voltage at the post is fine, but doesn't help if there's an issue in the power cord or reel (or loose/corroded connections at the transfer switch).

Re: Front AC tripping transfer switch

Reply #13 – June 05, 2023, 05:57:57 pm

I keep my plug out of the block heater receptacle incase the switch gets turned on and if I need
it I will plug it back in.

Re: Front AC tripping transfer switch

Reply #14 – June 05, 2023, 06:01:00 pm

Peter now that you mention that I remember kicking it on or hitting it with the vacuum.

Re: Front AC tripping transfer switch

Reply #15 – June 05, 2023, 08:39:22 pm

I would check the ac to coach connections lin the junction box at the air conditioner.

Re: Front AC tripping transfer switch

Reply #16 – June 06, 2023, 12:31:21 am

Quote from: Pamela & Mike – June 05, 2023, 02:50:33 pm

Frank,

While you were changing out the capacitors did you see another device on the floor close to the capacitors? It would be mostly black with a couple of wires coming out. If so that is a PTCR or something like that. (long time sense HVAC school) Think of it as a supper boost for the start windings. If it is bad it could cause some of your symptoms.

In some of your statements you have said "it has been running for 30 min" Now for some clarification: Are you sure that the compressor is running and not just the fan motor.

Mike

https://www.youtube.com/watch?v=s0TzajhoA2Y

Re: Front AC tripping transfer switch

Reply #17 – June 06, 2023, 07:56:54 am

First question, does the transfer switch cycle on/off the same if you use generator for your power? If so, I would not think it's the cord reel. Suspect front AC is causing problem. I had a fan motor going bad, you could watch the amps slowly creep up until it popped a breaker.

Re: Front AC tripping transfer switch

Reply #18 – June 06, 2023, 09:33:14 am

I'll take a stab at this.

The transfer switch doesn't "cycle" , it simply switches power from one source to another. Shore / generator, depending on which is wired as a priority.
If you have "auto gen start" and shore power is lost or drops below a set point for a determined amount of time the transfer switch will switch to the generator side after it detects voltage from the genset. If your transfer switch shore power contractor is dropping out when you start a large load ( roof AC ) then it must be sensing low voltage for some reason. Poor connection in the pedestal? or power cord? contractor terminals where the sensing relay is connected?

Just some thoughts on this, remote trouble shooting can difficult. 🤷‍♂️

Re: Front AC tripping transfer switch

Reply #19 – June 06, 2023, 09:36:41 am

Easy test if its the reel... While the ac is on... Take the reel and turn it in and out slowly back and forth... If it kicks off at any point you have found the problem... If the reel had an issue the next problem is the transfer switch.. Replace it as needed because it will tear it up connecting and disconnecting like that.

Re: Front AC tripping transfer switch

Reply #20 – June 06, 2023, 02:39:30 pm

Quote from: John Duld – June 05, 2023, 08:39:22 pm

I would check the ac to coach connections lin the junction box at the air conditioner.

Thanks John, when I replaced the capacitors and PT,CR I checked them

Re: Front AC tripping transfer switch

Reply #21 – June 06, 2023, 02:42:39 pm

John H.

does the transfer switch cycle on/off the same if you use generator ? No it doesn't.

Re: Front AC tripping transfer switch

Reply #22 – June 06, 2023, 05:35:30 pm

Quote from: Lt403 – June 05, 2023, 03:25:59 pm

Keith,
That is the xfer switch I'm talking about.
They have mentioned the hi lo potentiometers before but I haven't touched them yet, I see the red dot and the slot but really can't tell how it's read

Mark where they are now. Turn the high all the way up and the low all the way down, which should give you more range for it to engage within, since you already know your incoming power is within spec due to your Surgeguard unit. Does that stop the cycling? You can always turn them back to where they were later.

Re: Front AC tripping transfer switch

Reply #23 – June 06, 2023, 08:11:10 pm

Thanks everyone for your input.
Last night I slept with only the rear AC to avoid any electrical issues

This morning I shut down the rear AC and disconnected from the pedestal and opened up the transfer switch box.

Reconnected shore power and check voltage at the shore power transfer switch, which I had 124 and 123.

However, I still did not have power to the coach. I pulled the shore power cord and retracted it again, and still no power to the coach .

My next step was to increase the "hi" orange potentiometer ever so slightly. I may have moved it 1/64-1/32 when I heard a click at the potentiometer and then the transfer switch activated and I had power to the coach.

I have not had the problem since.

Will see what happens tonight.

Sorry for the late reply it's been an interesting day.

Re: Front AC tripping transfer switch

Reply #24 – June 06, 2023, 08:19:10 pm

Quote from: WS6_Keith – June 06, 2023, 05:35:30 pm

Mark where they are now. Turn the high all the way up and the low all the way down, which should give you more range for it to engage within, since you already know your incoming power is within spec due to your Surgeguard unit. Does that stop the cycling? You can always turn them back to where they were later.

n.b. We have learned the transfer switch does not cycle on generator when the AC starts, so that points to something on the shore power end of things. While the plug in surge protector says voltage is fine at the post, that does not rule out issues in the shore power cord, reel, or connection to the transfer switch. I would say the Over/Under relays are at least working to some degree since they allow generator power to pass, but not shore power under load on one of the 50 amp legs.

OP has also mentioned the Intermatic device lights showing an issue (Female, weathertight, shoreline plug ). That again points to something (potentially) between the shore connection and the transfer switch. OP has also indicated a possible issue with the shore reel:

Female, weathertight, shoreline plug

I would be hesitant to disable the over/under protection relays in the transfer switch until it's verified that they, and not the shore reel or connections to the transfer switch, are not the problem.

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