Eddi issues

graememk

https://www.boards.ie/discussion/comment/120246246#Comment_120246246

The immersion likely only goes down half the tank

Either get a longer immersion or an external one

Redlim

https://www.boards.ie/discussion/comment/120246497#Comment_120246497

Ah ok cheers, was hoping there might be something simple that I was missing that could help sort it but that makes sense.

I presume the old sink/bath switch prior to getting the solar and Eddi installed had the exact same issue but it wasn't something I ever checked as we didn't use the immersion much before solar.

Redlim

https://www.boards.ie/discussion/comment/120246404#Comment_120246404

Sorry only saw this post after replying to graememk. Would be great if it was just a wiring issue but what graememk said about the element only going down halfway makes sense.

graememk

https://www.boards.ie/discussion/comment/120246587#Comment_120246587

If you boost tank 1 how much power does it use?

If you boost tank 2 how much power does it use?

The higher one is the "bath" element.

My immersion gave up, and I got it replaced with one about 9" longer... And it's still not long enough!

If I ever get the tank replaced it will have separate immersions

cobham

Now I am more confused! I think I need an electrician to explain how a water storage tank with two heating elements and one thermostat works when heat rises to the top and that is where the thermostat is located. I know I can set up the bigger immersion heater to come on whereby power might come from the grid when not enough solar available. But this defeats the purpose of the Eddi using the water to store excess solar. Lashings of hot water was one of the attractions of getting the solar installed. A full tank of hot water on a sunny day would help out with the following day if cloudy with just the back up boost of the smaller element for short times for essential hot water.

con747

https://www.boards.ie/discussion/comment/120246752#Comment_120246752

When you look at the Eddi screen when there is excess it will show how much power it is using, then you know which part of the element is heating the water if you have a a twin element. What @graememk means is the higher power it is using is the bath element and the lower power one is the sink element. So if it is using about 1.5kw it is heating the sink element, if using about 3kw it is heating the bath element. Check the Eddi screen to see what is being used.

Redlim

I've just tested the readings on my own Eddi using the manual boost function.

Tank 1 gets up to 2.8kW

Tank 2 gets up to 2.0kW

So it looks like mine is wired where Tank 1 is bath and Tank 2 is sink.

I assume I should just leave the priority at Tank 1 (bath) so that it can heat at a higher rate if there is enough surplus solar. It also potentially heats a bit lower into the tank if the bath element is bit longer?

And I guess the only way to start getting a full tank of hot water is to get a full length element. Is it possible to add a separate external stat to the lower part of the tank or could this be dangerous as the bath element might never be able to heat down that low?

slave1

Photos, we can't assume element power here, my elements are identical power top and bottom. There should be a metal surround on each element that you can screw off via small nut and that MAY show element power. If your bottom element is turning off quickly (thinking max temp reached) then you will only have half a tank of hot water. It could be nothing to do with the EDDI, your bottom element could require a new temp stat or even a simple reset (should be a tiny white/black button to depress when you screw off the metal surround, if it clicks when depressed then it's reset) due to high voltage incident in the past.

If you're not comfortable taking the element cover off then don't, up to you

graememk

https://www.boards.ie/discussion/comment/120247264#Comment_120247264

Yeah leave priority at 1, the higher power one is the longer one.

Theres a few options

A longer immersion,

An external immersion, a Willis immersion will heat the whole tank.

Or a de stratification pump, this can mix up the tank allowing all of it to be heated, if you get a relay board for the eddi, it can be controlled from the eddi.

https://www.boards.ie/discussion/comment/120249286#Comment_120249286

It's one of these immersions, that go in from the top, that share a thermostat

https://www.heatmerchants.ie/heat-merchants-36-dual-immersion-element-immersion-u47239

not 2 separate immersions. That usually come in new tanks.

Redlim

Thanks @graememk ,a few options for me to consider there. You are correct that my immersion is at the top and pointing down into the tank. I have added a picture below.

@slave1 mentioned the metal cover. Is there usually a temperature dial under the cover that allows adjusting the cut-off? If I was able to raise this a few degrees then I'd have more useable hot water perhaps.

Hellrazer

In my case the immersion was tripping the rcds and it was kind of a rush to get the immersion fitted - It had been in the tank for probably 40 years.

I couldnt find a 36" one anywhere and ended up with a 30".

My installer said it was better to only connect one element of the Immersion - the long one as my water was supplemented with gas heating.

This means it heats from the bottom but like @Redlim mine was only heating the top 2 thirds of the tank as the element was slightly shorter than the one that came out of the tank - So what I did was limit the Eddi to 1.0kw - 1.5kw as recommended on the Eddi forums.

Its heats slower but theres a lot less stratification and Im getting almost a full tank now before the max temp on the eddi kicks in. What I reckon is happening is that with the slower heating the colder water has more time to drop to the bottom of the tank as its denser and is getting heated so Im getting a better volume of hot water.

https://myenergi.info/eddi-disable-tank-1-t6705.html

Im going to experiment with this and see how it goes over Summer. I might need to increase the thermostat on the immersion as at the minute the gas heating is also contributing to the hot water tank heating.

But for a couple of days last week without the heating on the eddi supplied enough hot water without gas top ups and we had a full tank of hot water.

Im considering fitting a new tank next year but this seems to be working for the minute.

Redlim

That's interesting, thanks @Hellrazer. I guess at this time of year that concept should get tested automatically as the Eddi isn't normally diverting at full power anyway. Definitely something I'll keep an eye on though.

You mentioned you might adjust the thermostat in the immersion. Is that thermostat under the metal cover like the one in my picture earlier?

Hellrazer

https://www.boards.ie/discussion/comment/120258561#Comment_120258561

Yep its under the cover - probably a small philips screw or flat head.

cobham

Trouble tonight with cold water from tank despite morning and evening boost set by timer and a day of good sun. No one was using hot water during the day but tonight it is virtually stone cold. During the day the Eddi was displaying two blue lights on and 'maximum temperature reached'. Something very wrong but where to start?

It would not let me do a manual boost as it said 'max temp reached'.

I think problem is with the MyEnergi app which is displaying some yellow warning triangle.

graememk

https://www.boards.ie/discussion/comment/120267193#Comment_120267193

check the thermal button on the immersion, it might have got too hot. (and appear as max temp reached to the eddi)

cobham

Where is that located? maybe should turn off the Eddi? and reset??

graememk

https://www.boards.ie/discussion/comment/120267341#Comment_120267341

take a pic of the immersion thats in your hot water tank and we'll go from there.

cobham

immersion.jpg

Is this enough?

graememk

https://www.boards.ie/discussion/comment/120267624#Comment_120267624

Not quite look at the very top looking down there possibly is a little red button, that you can push in with a pen

cobham

Right I have done that and the Eddi lights have turned off. I had a duvet over the top of the immersion ....wrong?

graememk

https://www.boards.ie/discussion/comment/120267735#Comment_120267735

That possibly could do it. Does the boost work now

cobham

Yes boost came on .... I think I will omit the early evening timer setting and do a manual boost on a sunless day. I will leave the top of the immersion/thermostat uncovered. I hope I dont have to keep doing this! Thank you for your interest and help Graeme.

Hellrazer

If its tripped the reset once it will more than likely do it again.Whats happening is that the top of your tank is getting too hot too fast and tripping out the overheat protection on the immersion( the red button) while the rest of your tank is probably colder Im guessing.

Its a learning curve with regards to the eddi and immersions. Its like it just needs a bit of tweaking to get it to suit you and your household.

Try what I said with limiting the power to the immersion @ 1.5kw

What Ive started doing and what works for our house is let the eddi take the excess from the solar until it reaches max temperature and then turn I it to stop mode using the app so then its exporting the excess back to the grid. I still get a tank of water and if I need to top up I just switch off the "stop" mode in the app or just boost it. By doing this I think its allowing the water to circulate better. You could also let the eddi check the temperature every 45 minutes instead of the default 15 minutes- again allowing more time for the colder water to circulate - I havent tried that yet myself.

The eddi by default checks the thermostat on the immersion every 15 minutes and then if its below temperature will attempt to send excess to the tank but I feel that 15 minutes is way too short especially if you have w really well insulated tank and a short immersion thats heating too much of the top of the tank.

You could also try increasing the thermostat on the immersion itself. Its probably set to 55c out of the box. Give it another 5c and see if it changes anything.Its that little brass nut on your first picture - loosen that off, the cap will pull off and then underneath is a place for a screwdriver with usually the temperature in 5 degree increments up to either 65 or 70c. Id try it at 60c and see how it goes.

Make sure the power is off at the fuse board before taking the cap off though.

graememk

https://www.boards.ie/discussion/comment/120268162#Comment_120268162

What tripped is the backup cutout not the normal thermostat, a failsafe if you will. That one is not adjustable.

@cobham keep an eye on it, when mine started cutting out, the immersion had burned out. Nearly melted the insulation off the wires before it did. ( But it tripped quickly)

Seeing as you had a duvet over it could have triggered it too.

Just keep an eye on it and it trips again, new immersion time.

Hellrazer

https://www.boards.ie/discussion/comment/120268210#Comment_120268210

The reset button is for over heat protection as well as a safety protection if the immersion has gone bad but usually the RCD will trip first if the immersion is bad.

It could be the duvet, it could be the eddi heating the top of the tank too fast which seems common reading the myenergi forums, it could be a faulty thermostat, faulty immersion, loose wire at the immersion.

Its a process of elimination.

By increasing the temperature on the thermostat it gives a greater margin of error before the thermal cut out trips or by making sure the water is heated evenly - and its probably the easiest one to try first and check the wiring while the cover of off.

Next its probably a new immersion element.

graememk

https://www.boards.ie/discussion/comment/120268420#Comment_120268420

Not necessarily, mine was on a rcbo, never tripped it

But adjusting the thermostat has no effect on the thermal cut out. (Unless you raise the thermostat to above the thermal cut out)

But I agree it could be the thermostat gone too if the immersion is still heating.

I can understand why there would be immersions failing on the myenergi forums, prob was used very rarely and then the eddi comes along and then gives up.

Hellrazer

https://www.boards.ie/discussion/comment/120268470#Comment_120268470

Thats what happened with mine. Worked perfectly until the eddi went in. Reset tripping, rcbo tripping etc. Took the immersion out and it was cracked down the middle - but it was still heating the water.

The RECI said its common if an immersion is in place for decades.

DC999

https://www.boards.ie/discussion/comment/120268718#Comment_120268718

A family sparks told me immersions and electric showers are main reasons for tripping. Makes sense - water and a lot of electricity. Immersions are often older then the people who own the house. He removed a damaged immersion for us that kept tripping. Was in the gaff when I bought it 30 yrs ago. God knows how old it was. And it's sitting in water :)

cobham

All well this morning, boosted on timer and now charging with solar when excess. It is relatively new tank and immersion, I suppose 10 yrs old now and we always used the sink immersion for water heating via a timer. This was a habit of previous set up that had a larger tank and back boiler link. We have gas now for c heating but never could work out if it made sense to use gas to heat the full tank or continue with electric and keep small amount 'hot' which was enough for two showers. Now we have a pump on the water supply that amount seems to just 'do' for one shower.

If away for a few days, I think we will turn off the Eddi.

What does 'RCBO' and 'RCD' stand for?

graememk

https://www.boards.ie/discussion/comment/120269515#Comment_120269515

A RCD is a residual Current Device. You may know it as the trip switch or ELCB.

It monitors for a difference in current on the line and neutral, any imbalance means power has "leaked" generally to earth, usually trip at a low current about 30ma.

A Rcbo is a Rcd and mcb combined, a MCB is a miniature circuit breaker, they are used now instead of fuses.

Rcbo are used now so when a fault occurs it only takes out that single circuit not half (or all the house)

Glad your up and running again.