Tankless water heater now blows breaker, instantly

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Old 01-30-15, 11:46 AM
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Tankless water heater now blows breaker, instantly

Noticed I had no hot water today, and assumed the elements had gone again on my titan tankless. It is a cheap quality tankless heater that I've had trouble with in the past.

Anyway, this time I noticed no power, and after checking I got a nice flame/spark upon trying to jumper my disconnect at the unit and the breaker blew again.

Called Titan, and went through some checks on the unit for shorts using continuity checker. The tech rather quickly said my breaker was likely bad as we couldn't find any shorts on the unit.

At this moment, I'm not 100% convinced it's the breaker. This sort of thing has happened before, and I've gotten a new break, and it always turned out to be the attached appliance that was blowing the circuit.


May be a stupid question, but is there any way I can "sure" test for a short or anything that would cause this breaker blow on the water heater ? My panel is currently behind a big shelf. Got no hot water, no shower yet today, and the breaker is a 70amp double pole, so it's not cheap. Home Depot is 45 mins aways , and I'll stop whining now. Just want to be as sure as I can be on the breaker or a loose rail screw in my panel box before I go through all that work and expense to find out it was the heater again after all.

Incidentally, shortly after I bought this heater years ago, it sorta blew up, and I think was blowing breakers just as it is now. Back then , I got it replaced, and I think the damage was more obvious. So, this time I'm just not sure. Thanks for any ideas.

Forgot to add, I'm reading about 7.5 ohms across each element in the heater.. I'm not sure what that reading should be. I also checked for a short between the element and the copper mini-tank they are in, and found no short there.
 
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Old 01-30-15, 11:49 AM
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My panel is currently behind a big shelf
Not what you asked but this is a code violation - the area in front of the panel has to be open (best analogy is imagine a refrigerator box in front of it and that's the area you have to have open).
 
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Old 01-30-15, 11:52 AM
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I was thinking that as I wrote this. My panel door and access to breakers isn't blocked, but I have a rack in front of it, so actually taking the entire panel off would require me to move it out of the way. Do I have to pass commercial code inspection here? Hope not.
 
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Old 01-30-15, 12:14 PM
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Mitch,

Any idea on my breaker blow?
 
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Old 01-30-15, 12:31 PM
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Disconnect the wires to the breaker. If it will reset it is probably not the breaker.

Disconnect the wires from the water heater, cap with wire nuts, and reconnect them at the breaker. If the breaker doesn't trip when you turn it on it probably isn't the cable to the water heater. It is most likely the water heater.
 
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Old 01-30-15, 12:51 PM
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Thanks Ray. Not sure I understand your reply.

I have a disconnect at the heater, and the first thing I did was disconnect the heater, and reset the breaker. The breaker appears to reset and stay reset that way. It only blows when I connect the heater.

That's what I'm trying to find out is what are the chances of the breaker (or loose wiring in panel) causing the instant blow of the breaker when the heater is plugged in? In my understanding, it's unlikely, but then again I'm not sure because I don't know if breakers can fail in this way. I know the rail screws for neutral/ground in the panel can become loose over time.
 
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Old 01-30-15, 01:56 PM
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Open the disconnect at the heater and check the LINE side for power, 240 volts between the "hot" leads and 120 volts between each hot and the grounding connection. If that is okay then the problem is almost surely the water heater.
 
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Old 01-30-15, 02:08 PM
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the first thing I did was disconnect the heater, and reset the breaker. The breaker appears to reset and stay reset that way.
Then it isn't the breaker or the cable going to the heater. If it isn't under warranty I'd replace it with a storage type water heater.
 
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Old 01-30-15, 02:26 PM
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With the power off, check the resistance from each terminal on the heating elements to the metal case (ground). It should be infinity. If it's a shorted element the reading will be a positive number. The 7.5 ohms across the element is a good sign on the element's health, but you also need to check for shorts.

If the heating elements seem to measure OK on the resistance, so my guess is that the control module has shorted out. Could be relays or solid state components. In either case it's probably a part that needs to be replaced in its entirety from the manufacturer. Bad breakers are pretty rare compared to bad power control boards.
 
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Old 01-30-15, 02:42 PM
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I'm going to check some of these things now. I don't know why people that actually work as techs on these thing jump to such conclusions that don't make sense and call out breakers as being bad. AFAIK, a bad breaker is going to behave like a delayed trip, or a trip at an amperage lower than the breaker is rated for. For an instant trip like this, it's almost always going to be a short in the appliance or wiring. If anyone can confirm on me being correct on that , that would be great. thanks again.
 
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Old 01-30-15, 03:20 PM
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Found the culprit, and was inside the heater. Didn't notice this earlier, because it's on the bottom, and had to get on my knees to see it. As I was running around to get a breaker, the time passed, and the @@$$ at Titan picked up the phone, but wouldn't even let me order a part because they were closing.

I'm not sure, but I think the cause of this meltdown may be that slightly worn wire casing you can see in the picture. That is just a guess, and of course I don't even know if the unit works any longer.

Would like to know if that terminal block is even any "standard" or if I can try to fix even temporarily with a wire nut. Not sure based on the gauge of the wire. Thanks again for any ideas.

Here is a picture of the damage. Name:  IMGP9603.jpg
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Old 01-30-15, 03:21 PM
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AFAIK, a bad breaker is going to behave like a delayed trip, or a trip at an amperage lower than the breaker is rated for. For an instant trip like this, it's almost always going to be a short in the appliance or wiring.
That is correct. Use to do service on apartments with window ACs. Replaced a lot of breakers but it was because an Ampprob showed they tripped after a few minuets at a lower then expected amperage. Never had one trip instantly.
 
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Old 01-30-15, 05:44 PM
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Hard to tell from the pics but that looks like a terminal block if the conductors are long enough you can cut back the bad and resplice, you could probably find a suitable replace terminal block on line.
https://www.google.com/#q=3+pole+cer...ml%3B533%3B400
Geo
 
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Old 01-30-15, 05:51 PM
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Thanks! What I'm wondering about is:

1) What can cause that kind of meltdown? In other words, is the unit likely shot, or did that happen over time from some sort of partial short? Up until the breaker blow, the unit was putting out hot water OK, so I'm not sure.

2) Since Titan Tankless / Niagra is such a horrible company, I likely won't get a terminal block until sometime late next week. Gonna be tough with no hot water. I was thinking about temporarily using a split bolt or other suitable connector to splice together those leads, and leave the other two intact on the block. Would that be a no no?

Thanks for any help.
 
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Old 01-30-15, 05:56 PM
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I would bet loose connections at those terminals,doubtful if that would harm the elements,not sure what type of control board is close to that meltdown.
How big are the conductors? You could use a split bolt or appropriate sized wirenuts.
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Old 01-30-15, 06:01 PM
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That kind of melting was due to a bad connection. Then electrical connections are loose they create heat. Enough heat and things start to melt and start to burn. This is a common cause of fires.

You will likely find that the insulation on the wires has been damaged due to the heat (it will be very head and brittle). You will likely have to cut some back to get to good insulation. If it was me, I would bypass the cheap terminal block if you can't find one locally (they are pretty generic) and make a good splice.
 
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Old 01-30-15, 06:13 PM
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Thanks, and the loose connection makes sense. Geez, the thought of that being a fire risk sure is scary. I wired in this unit, and I think I even ran the thicker wire from my panel for it. I've worried about the whole "electrocution" thing with this crummy tankless, and now it looks like I'll have to worry about a fire from the connections. Now that you mentioned the loose connection, this sort of reminds me of the contactor on the AC. I think I should go tighten them some more , because I've seen burning action out there too over long periods of time. Now, that unit is outside, but I guess it could be a problem. Plus, the last time I worked on it, I partially cracked one side of the contactor, so I probably should replace it soon.

For the wire, that's 6 AWG I think. It's the same that runs to my AC. I found out they make some sort of monster wire nuts for this wire, but of course I don't have any right now. Based on research, I think a split bolt would be the cheapest and safest route. I'd need to tape it up of course.
 
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Old 01-30-15, 06:21 PM
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You need to tape it of course.
I wanted to point out stripping insulation off stranded conductors. You need to be careful not to cut into the strands when cutting the insulation. I have seen this too often where someone has used a utility knife and unknowingly have cut the strands so bad that there are only a few strands left. The nicked or cut wires just break and fall off upon tightening. It's a bad situation and accident waiting to happen.
 
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Old 01-30-15, 06:48 PM
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With that "quality" of terminal block I could see the connections loosing up over time due to the heating and cooling of the connections when the heater goes on and off. Also, it looks like the manufacture put more than one wire under the screw. This is a no-no for us in the field, but manufactures do it all the time. I am not a fan of that.

I would not be overly concerned about fires. This is why all splices are to be contained is some type of junction box or appliance. Your circuit breaker did exactly what it was supposed to do.
 
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Old 01-30-15, 06:57 PM
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Thanks and good point, Tolyn! On the topic of disaster, would you by chance be able to confirm on the risk of these lower quality tankless heaters somehow electrocuting through the water lines? Of course, I believe the unit is wired within code, and grounded, but I'm still not sure on exactly how that happens. When I researched it , it seems the only place this kind of stuff actually happens is in the middle east and places where it's nearly impossible to get a good ground though sandy soil.
 
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Old 01-30-15, 08:28 PM
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Pure water is a very poor conductor and if the pipes are metal they should be bonded to the electric system so a short should trip the breaker.
 
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Old 01-31-15, 09:21 AM
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techdiyfl, I also have an older Titan that went bad.

I then read good reviews on the Rheems. I ordered a new one from Amazon.

When the Rheem arrived, I put it side by side with my bad Titan, guess what? They look the same except the Logo and brand. Same size, some connections, same everything. Flip to the back side, all the mounting hole locations, where the wires come out, are all exactly the same.

So I am thinking these tankless are all made in some place in China, then Rheem, Titan, Bosch, Ecosmart or whatever order them made from the same supplier, then they spray paint the outside and slap on a logo in the US.
 
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Old 01-31-15, 11:40 AM
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While things appear to be the same, many times it is a case of counterfeiting. China gets a product they want to sell and they just make an exact copy of an existing product. No R&D required. The differences are in the quality of components, and customer service, the latter being the most expensive.
 
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Old 01-31-15, 12:20 PM
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A large blue or Greg wire but should be good for 2 #6s. Another option is a connector like a pre-insulated Polaris. A little pricey but a labor saver and less mess than taping a split bolt in a small area.
 
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Old 01-31-15, 02:16 PM
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Well, managed to get everything up and running with a small split bolt, tape, and a small piece of heat shrink tubing.

Even my marine shrink assortments wasn't big enough to cover the split bolt, but I think it is taped up OK. That terminal block was so fried that I was able to literally chip it out completely with a screwdriver and pliers, leaving just the remaining two parts intact. I pulled the 6 gauge back a bit toward the cover, and was able to meet with the two stranded wires going to the elements. I couldn't imagine doing this with anything other than a split bolt due to the small space and no length on the 6 gauge supply wire. I did cut off a small amount on the stranded, and retwisted. The stranded was the most difficult to get back in there, but I pulled on it, and all seems solid. Probably should've taken a picture.

One thing I was concerned about was the 6 guage wire looking quite cooked. However, that stuff is so thick, and only has a few "strands" to it, that I don't think it had lost its integrity.

I don't think I'm going to bother getting a new terminal block, since it seems that wire is the "problem" and the split bolt will hopefully do a better job at splicing it.
 
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Old 01-31-15, 02:25 PM
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Miami,

I think Bosch and a company called Rinnai are the ones that make the "good" tankless systems.

However, if I remember correctly, the wiring for the Bosch is even more crazy than these cheaper units like Titan. I think you need like 3 120v feeds or something crazy like that. That's also probably why they work better with more power... They also cost a lot more. Overall, I wouldn't recommend tankless, but going back to a tank would be nothing but more money and more pain for me right now. I'd have to re-plumb yet again, etc.

Not sure on Rheem, but Titan(Niagara) is out of Miami, and they are a HORRIBLE company to deal with on anything. As I may have already put in the thread, just yesterday I called them at 5, and they picked up the phone, but refused to help me because "it was 5". Prior to that, the morons that work in their service dept were the ones that told me this was "surely a bad breaker" problem. However, as I just found out with my car yet again, with all of these electromechanical devices you are most likely to get the best results by fixing it yourself, and most likely to get the worst results by trusting and paying someone else to do the work. Not just anyone either, the dealers and manufacturers are ironically often the worse source of service for the very equipment they claim to make and sell.
 
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