Author Topic: 2nd MTU stopped working  (Read 5170 times)

f16bmathis

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2nd MTU stopped working
« on: September 30, 2014, 06:26:53 PM »
Mid day, solar was putting out 500 watts or so, and I disconnected it. So MTU went to 0, all is good so far. When I turned the solar back on, the MTU for solar displays 0 watts. MTU blinks, is still connected as it was, all C/B's are good, just stopped reporting data!??

Support7

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Re: 2nd MTU stopped working
« Reply #1 on: September 30, 2014, 06:34:10 PM »
Hello f16bmathis,

If, after a few minutes, the MTU is still not reporting data, under advanced, click Reset Totals to Zero. It could also be helpful if you explain what you are trying to do/test with the system.

Best Regards,

TED Forum Support

f16bmathis

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Re: 2nd MTU stopped working
« Reply #2 on: September 30, 2014, 07:25:14 PM »
The test I am doing is actually a second post. The second MTU I use for solar has quit working. Shows 0 volts but it blinks, and I connected the clips up to my EV charger and it showed KWH's, so I'm confused at this point. It was working, then turned off solar and it quit when I turned the solar back on.

Resetting the totals to zero has done nothing. Still no data over WIFI.

f16bmathis

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Re: 2nd MTU stopped working
« Reply #3 on: September 30, 2014, 07:34:18 PM »
Weird though, I disconnected the clips from the solar, and connect them to the cars charger and it shows 3000 KWH and 120 volts, of course the 3000 and 120 is because I have it on 220 VAC and set up for 120, but the main thing is it reads voltage!

So why doesn't it work on 120?

Support7

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Re: 2nd MTU stopped working
« Reply #4 on: September 30, 2014, 07:42:58 PM »
Hello f16bmathis,

How are you powering the MTU? The voltage reading comes directly from the power cable that is supplying the power to the MTU. The CTs do not have any affect on the voltage reading. If you have KW readings from the MTU when the CTs are placed on the EV charger, but zero when the CTs are placed on your solar feed, you may have a problem with your solar feed.

Best Regards,

TED Forum Support

f16bmathis

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Re: 2nd MTU stopped working
« Reply #5 on: September 30, 2014, 07:50:28 PM »
Wow, now it's getting really weird! Cause I just pulled the MTU's clips off the 220, black and red mains, and connected one to the red main and the other to the solar breaker (had it connected to the Black main and the solar breaker) (or maybe I messed up?) and now it shows voltage. DID NOT DISCONNECT THE MTU's POWER LEADS.

So the clips MUST have something to do with voltage readings.

But whatever...I'm running about 100 watts (cloudy today) and Ted shows about 2 watts (.002 kw)

Support7

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Re: 2nd MTU stopped working
« Reply #6 on: September 30, 2014, 07:57:02 PM »
Hello f16bmathis,

Make sure you put the CTs in the correct orientation. The red dots should face the source of power they are reading.

Best Regards,

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f16bmathis

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Re: 2nd MTU stopped working
« Reply #7 on: September 30, 2014, 08:01:35 PM »
Yes, I tried them both ways, but it works in a negative direction, which is what I want, when the red dots are facing towards the solar production. I do have it set in footprints as generation.

f16bmathis

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Re: 2nd MTU stopped working
« Reply #8 on: September 30, 2014, 08:19:10 PM »
And weird gets worse. Didn't touch it, and now its at 0 volts again!

Support7

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Re: 2nd MTU stopped working
« Reply #9 on: September 30, 2014, 08:23:13 PM »
Hello f16bmathis,

Where is this MTU being powered from?


Best Regards,

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f16bmathis

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Re: 2nd MTU stopped working
« Reply #10 on: September 30, 2014, 08:32:56 PM »
I have a sub panel with 220. The MTU is powered by an unused breaker on the left side. I have the solar connected to a breaker two spots down, so same leg... The clips have the red dots facing towards the solar production, and are currently connected to the left (red) of the 220 and the breaker on left two spots down.

Support7

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Re: 2nd MTU stopped working
« Reply #11 on: September 30, 2014, 08:35:43 PM »
Hello f16bmathis,

The CTs should both be on the lines of the solar feed. One on each feeder leg. Is that how you have them installed (also make sure they are fully closed or you'll get odd readings).

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f16bmathis

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Re: 2nd MTU stopped working
« Reply #12 on: September 30, 2014, 08:43:53 PM »
Ah, well, The solar feed in has one connected to the breaker I've got the one clip on, and the solar neutral is connected to the subpanels white neutral wire. Solar is only 120.

So anyways, I pulled the MTU's black wire and connected it to another breaker and now it's working, voltage and displaying KWH's close to what my watt meter is showing. So I must have had the power on the wrong leg? Yeah, it's still working KW and V!

Maybe I should put the other CT on the neutral wire, same as the solar?

Support7

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Re: 2nd MTU stopped working
« Reply #13 on: September 30, 2014, 09:03:00 PM »
Hey f16bmathis,

You can just let the unused CT hang. You won't read correctly if you put it over neutral.

Best Regards,

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f16bmathis

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Re: 2nd MTU stopped working
« Reply #14 on: September 30, 2014, 09:16:05 PM »
Hey, What do you know that did the trick! And I was just looking to get a voltage reading!

So fix for no voltage reading and inaccurate reading when it did read is to...

Place only one CT on solar coming in (red dot facing towards PV)
Move MTU power (black wire) to a different breaker (in effect changing the leg it was on)

Awesome job! Thanks for the help!