Power delay from shore to 5ver - Montana Owners Club

shorthauler · 08-06-2023, 07:17 PM

Hi everyone, I recently thought my microwave was going bad because the numbers wouldn't light up for a couple of minutes after I hooked up to shore power but after plugging in at camp the other day I had no power in the rig for about 5 minutes then everything started working. I have a EMS-PT50X surge protector and it showed power to the rig was fine (no problems). Has anyone else had this issue? Am I looking at a converter going bad? It seems like the delay is getting longer but once I get power then I'm good until I unhook and head home (was hooked up the 6 days) then when I get home and plug in it's another delay.

Ralph
2020 3120 Legacy

NCFischers · 08-06-2023, 08:26 PM

What you are experiencing is normal. The EMS has a built in 2 minute and 20 second delay (roughly). This is so if the AC units have any head pressure built up they can equalize before they try to start under pressure. It’s a safety feature. Some AC units have a built in delay and some EMS units have a switch to shut the delay off. You don’t have a problem.

shorthauler · 08-06-2023, 08:43 PM

The delay happens even without the surge protector plugged in. I plugged it in because I had a problem and was checking the power coming in. I don't use the surge protector all the time, just depends on where I'm at and the surrounding circumstances.

**Carl n Susan** · 08-06-2023, 08:49 PM

Did you buy this unit new or from a previous owner? It is possible there is an on-board EMS system in addition to your portable unit? That would explain the 2+ min delay and the 5+ min delay when you use the portable PD unit.

shorthauler · 08-06-2023, 09:15 PM

I bought it new and it has an onboard surge protector that came with the legacy package but up until now when we plugged into shore power the lighted numbers on the microwave would be flashing right when we opened the door until I set the time. Now nothing shows up but after a few minutes the light inside the microwave will start working and then I hit the set clock button and the lighted numbers come on. Also the frig flashes no ac and we have never seen that before although it could have been there.

**Carl n Susan** · 08-06-2023, 09:23 PM

The EMS-PT50X you mentioned above is the portable unit used at the power pole. You say there is also an on-board EMS unit. The behavior you are seeing (2+ and 5+ min delay is consistent with the use of 1 or 2 EMS units). Obviously you only need one EMS unit.

As to the past experience where power was available immediately, I have no good ideas. Could it be the on-board unit was "bypassed" or you were using a generator?

shorthauler · 08-06-2023, 09:48 PM

I was thinking maybe the onboard wasn't giving the delay but now is. I bought the portable one because it shows what the problems are if any and the onboard doesn't. I guess as long as it comes on I'm good. Thank you both for the feedback.

Tomcat3rd · 08-16-2023, 11:33 AM

Quote:

Originally Posted by shorthauler

I was thinking maybe the onboard wasn't giving the delay but now is. I bought the portable one because it shows what the problems are if any and the onboard doesn't. I guess as long as it comes on I'm good. Thank you both for the feedback.

Hi shorthauler,

I've had a similar problem where the power from the post looked good on my portable surge protector and would look ok for a bit in the trailer and then one leg of the AC power would fail. Long story short, it turned out to be the onboard EMS surge protector was failing. When it finally failed I couldn't get any AC power into the coach, which was a major problem. I found a great RV center in Billings, MT, Pierce RV, and they quickly found the problem and replaced the part and I was on my way. You might want to have yours checked too. It's located behind the bulkhead near my water heater in my 2019 Montana 3931FB. Once changed all systems were normal. Hope this helps.

Tom & Sondra Chambers
2017 F-250,

firestation12 · 08-17-2023, 08:45 AM

Quote:

Originally Posted by Tomcat3rd

Hi shorthauler,

I've had a similar problem where the power from the post looked good on my portable surge protector and would look ok for a bit in the trailer and then one leg of the AC power would fail. Long story short, it turned out to be the onboard EMS surge protector was failing. When it finally failed I couldn't get any AC power into the coach, which was a major problem. I found a great RV center in Billings, MT, Pierce RV, and they quickly found the problem and replaced the part and I was on my way. You might want to have yours checked too. It's located behind the bulkhead near my water heater in my 2019 Montana 3931FB. Once changed all systems were normal. Hope this helps.

Tom & Sondra Chambers
2017 F-250,

While surge protectors are less expensive, I think the consensus about surge protectors is they fall short of monitoring all the electric parameters that an EMS does, as well as protecting the a/c compressor from premature start up after a momentary interruption.

shorthauler · 10-01-2023, 02:36 PM

I'm back to the same problem but worse. Haven't camped since the last time I posted so when we arrived at the RV park it took about 25 minutes for the power to come on and then we were fine for the three days we stayed there. The green surge protector ligfht would come on instantly but no power for 25 minutes. We were not using the portable unit just the onboard one. When we got home today the light comes on but no power for 2 hours now so I swapped out the GIF in the bathroom but that didn't help so where do you guys suggest I go from there. Thanks in advance.

Ralph & Nadine
2020 3120 Legacy

**Carl n Susan** · 10-01-2023, 05:25 PM

Quote:

Originally Posted by shorthauler

...I swapped out the GIF in the bathroom but that didn't help....

GIF or GFCI?? If GFCI, it has nothing to do with your power delay. It is waiting for your EMS to pass power to the circuit breaker panel an then to it.

Have you tried using the "Bypass" mode on the onboard EMS?

firestation12 · 10-01-2023, 05:40 PM

Might be time for the OP to positively identify the device he describes as “onboard”. Does the 3120 legacy by chance come with a generator option which would have a transfer switch?

Theunz · 10-01-2023, 05:45 PM

I don’t know anything about the factory EMS, but I can’t think of anything else that would cause a delay. If there is no bypass or if the bypass doesn’t work then if you feel comfortable doing so you could just wire around the EMS. That would eliminate the EMS as a source of your issue. I’d be very surprised if you don’t have a faulty EMS. Good luck and be cautious!

**Carl n Susan** · 10-01-2023, 05:52 PM

Faulty Transfer Switch - yet another potential source. A 2020 model seems to be the right time frame.

RMcNeal · 10-02-2023, 03:47 AM

Carl beat me to it. The transfer switch was my guess as well.

shorthauler · 10-02-2023, 05:06 AM

Our rig does have the generator prep so I will look for the transfer switch and test it. Thanks everyone.

Ralph & Nadine
2020 3120 Legacy
2016 F350

firestation12 · 10-02-2023, 08:56 AM

Quote:

Originally Posted by shorthauler

Our rig does have the generator prep so I will look for the transfer switch and test it. Thanks everyone.

Ralph & Nadine
2020 3120 Legacy
2016 F350

Normally the default contactor position inside the transfer switch would be to throughput the shore power and only switch if voltage was seen from a generator. Yours may have been wired to do the opposite. Should the transfer switch fail then
Your camper would have access to shore power.

Tomcat3rd · 10-02-2023, 10:12 AM

I’m not sure if your unit has the same transfer switch mine did but if this photo helps this is what you’re looking for. Mine was located behind the bulkhead in the basement next to the water heater mounted vertically on a big plywood board. .

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