Water heater is kicking out the power

[canuckamuck]

Uhm - if you or yours needs to have a hot/warm water bucket splash, BOIL some water and add it to the bucket. Using the shower unit for that at low flow (like others say) is probably causing your problem and not the way to do it. It would be much more efficient to heat water in the kettle or over the coals in a pot. C'mon... THINK.

Yeah, it ain't me.

[Crossy]

I'm still concerned that it's opening a big breaker, even if full of air it should be protecting itself by shutting down.

[canuckamuck]

I'm still concerned that it's opening a big breaker, even if full of air it should be protecting itself by shutting down.

It's a puzzle for sure. There two breakers on the line. One near the heater. and one at the unit. both of them 20 amps. But it's the main that trips and that doesn't make sense to me. I will be looking for a new heater, but that doesn't let me know what the problem is with my consumer unit. Or if there is one.

[Crossy]

I'm still concerned that it's opening a big breaker, even if full of air it should be protecting itself by shutting down.

It's a puzzle for sure. There two breakers on the line. One near the heater. and one at the unit. both of them 20 amps. But it's the main that trips and that doesn't make sense to me. I will be looking for a new heater, but that doesn't let me know what the problem is with my consumer unit. Or if there is one.

If you are certain it's not an RCD of some sort that's opening (an RCD will have a 'Test' button) it is possible that the incoming breaker has gone sensitive.

I have a 40A MCB that was protecting our water pumps (total of 6HP). It kept tripping so I replaced it with a 20A that was 'in-stock' intending to replace it when I had time (and remembered to buy a new 40A MCB). The 20A has never tripped so has not reminded me to replace it.

[canuckamuck]

Ok here is the unit. The picture shows what it looks like after the shower has tripped the power. Breaker A which the box lists as the main, is open.

Normally when I get a leakage fault both A and B will be opened and the little black rectangle (leakage indicator) will be popped up. And then I will have to push it back in before I can push the breakers back up. But in this case all I have to do is push up the main and everything is back online. So i don't think there is leakage.

[Crossy]

I would be tempted to replace the incomer,shouldn't be expensive.

We have a 50A incomer which has never opened and we have pushed the envelope somewhat, a 50A will carry a 20% overload pretty well forever.

[canuckamuck]

I'll look for one when I get to town tomorrow.

[bankruatsteve]

I haven't see that mfg. or configuration for CU before - maybe just me. BUT - if the main breaker AND the RCBO breaker both break when you do the test button then there must be some type of (strange?) connection between them. It looks like you have your RCD sensitivity on something less than 30ma? If so, maybe change to 30ma. Anyway... there is no reason for a 50a breaker to break when there are several less amp breakers in between for over-current. Like Crossy said, maybe it's gone sensitive. Maybe there is some kind of connection between your RCBO and the main breaker that trips it on a fault. (?) If you don't use your shower for purpose of heating a bucket and that solves your problem, then leave it at that. Cheers.

[Crossy]

Steve, there's often a little tab on the RCD lever that pushes the MCB out when the RCD trips, doesn't do it the other way round. Perhaps our OP can post a close-up photo of that part of the board.

I do sometimes wonder about these CUs with 8 units taken up with an RCBO that could easily be just a (readily available) double width RCBO device.

CKY are here http://www.ckythai.com/products.html

EDIT The CUs with RCBO do appear to be DIN mount so any of the big name units should fit.

[canuckamuck]

I fixed the filter inlet to the heater, it doesn't drip any more so no more air sucking inside ( I thought it was a little valve but it is a little filter instead). Anyhow everything seems to be working. I can't make the water heater trip the breaker any more. I even tried with a 2000 watt kettle on at the same time plus whatever else was on in the house at the time. The main doesn't trip. However, I did buy a new incomer and if I have another problem I will swap out the old one, I was just hoping to see if I could prove it was faulty first.

That being said, I do have a question about my RCBO. At the bottom of the RCBO unit. there is a little switch that simply says on/off. In my little brain I am thinking that 'on' would turn on the RCBO and 'off' would switch it off. However it functions the opposite to this. The RCBO only seems to work when the switch is in the 'off' position. By work I mean that the test button shuts down the system only when in the off position.

I have included a picture so you can see what I mean. What is this on/off switch? is it a bypass for the RCBO?

[lopburi3]

Believe it is a bypass switch and the on means the bypass mode in on (not good logic but have seen such on others here). Just make sure you have set so the test switch trips the breaker.