Help me troubleshoot why I have no hot water with an iBoost

Cottage_Economy

Hi all

As the title says, I have no hot water. Since our panels were put in with an iBoost in March we have had toasty hot water all day. I put the hot water to come on by timer, as recommended by the installer, for about an hour or so in the evening just to ensure the tank is nice and hot for the following morning when my DH gets up around 5am.

However, I've just had a cold shower. Bit of a shock to the system :eek: but as I am going out tonight and I was already wet I had no choice but to carry on.

The iBoost is saying the water tank is hot, the iBuddy claims it is exporting over 2kw to the grid.

I advanced the hot water timer and fired up the boiler about an hour ago and now the water is hot. A win for my husband as he will be using it shortly.

Why is the iBoost claiming the tank is hot if it is not?

Is this an iBoost problem rather than a heating system problem? Or has my thermostat failed?

mmmmikey

Brrrr - I hate cold showers.

Could be either the iBoost or the thermostat. Do you have a mains testing screwdriver, the kind with a light that comes on when you touch the tip on something live? And are you confident and cautious when working with electricity?

If the answer to both those questions is yes, then you can start by taking the cap off the immersion heater. Extreme caution is needed here as that potentially exposes live wires, so don't leave the cover off, especially if you have children or pets. I don't have an iBoost but guess it must have a manual override / boost setting. If you put it on this setting and touch the two thermostat terminal with a screwdriver one at a time and only one of them is live, but the water isnt heating but cold, then that points to a problem with the thermostat. If neither of the terminals are live then that points to a problem with the iBoost.

Forgive me for saying this if it is obvious to you, but make sure you put the cover back on the immersion heater as soon as you've done this, even if neither of the terminals are live. Also, if neither of the terminals appear live, test the tester by carefully touching some that is live, for example remove a light bulb and touch the contact where the bulb screws in and make sure the tester lights up. Just because the tester doesn't light up, don't assume what you are touching is dead - it could be the tester not working. Again, apologies if this is obvious to you, but this is better said than left assumed.

btw the immersion heater cover is usually held on with a single small nut and easy enough to remove.

Hope this helps - once you've tried this if you post back someone here can suggest next steps

pinnks

Diverters like the iBoost are just clever switches that turn on the immersion heater and allow it to demand only as may watts as would otherwise be exported to the grid. So, if the iBoost suggests it is heating the tank my first port of call would be the immersion element or its thermostat.

My first question though, is why your installer suggested turning the DHW system on in the evening during the summer months? I turn my boiler off when the central heating goes off in March or April and back on when the heating goes on in the autumn. For the rest of the year I get 99.9% of my hot water from my diverted PV. Only on really bad days do I need to top up and when I do I use the override or boost facility on my diverter to run for 30 minutes (1.5kWh) to 1 hour (3kWh) to heat the water. This must be more efficient that heating the boiler and all of your pipes between boiler and tank (and back to the boiler).

Anyway, to test your system, try overriding the iBoost so that it just turns the immersion heater on and powers it irrespective of your excess generation. You should see the immersion taking about 3kW and it should be hot in about an hour. If that does not give you hot water then I would think you have either a faulty thermostat or a blown element in the immersion. The latter would be likely to cause a circuit breaker to trip, so my guess would be the thermostat.

If you get hot water by the above test, then it would point more at the iBoost not doing its job. That could be the CT sensor that measures import/export near your meter or the unit itself.

Others will no doubt chip in with additional thoughts.:beer:

Just noticed mmmmikey sent his thoughts while I was typing...

mmmmikey

pinnks wrote: »

Just noticed mmmmikey sent his thoughts while I was typing...

Yes we crossed posts Suggest you start with pinnks approach.....

legoman62

I use one of these for testing, just run along the outside of the cable.:D
https://cpc.farnell.com/tenma/72-750/voltage-detector-90-to-1kvac/dp/IN07432?st=voltage%20detector
Have you checked the batteries in the sender unit?
Or
https://www.marlec.co.uk/trouble-shoot-my-solar-iboost/?v=79cba1185463

1961Nick

It has to be either the thermostat or the element. Hopefully it’s the thermostat because it only takes a couple of minutes to change one.

The iboost is assuming the tank is at temp because there’s no current flowing.

If you’re not familiar with using a neon screwdriver - get an electrician or someone who is competent to do it for you. Immersion heaters are often on a 32a breaker with no RCD protection. It probably won’t kill you, but it’d be quite a big bang if you get it wrong.

Cottage_Economy

Thanks all.

I have shown DH this thread and he is going to do a bit of investigating today. I will post back later what we find.

I can say that the batteries in the sender unit are fine as we changed those recently and cut back an enthusiastic rose from around it. No circuits have blown on the main board.

My money is on the immersion thermostat.

Cottage_Economy

Hi all

Well, did the test and put the iBoost on manual boost. Nothing really happened. The water was hand hot coming out of the tap (it should be steaming) and there was no current pulled in from the grid.

I've called the heating engineer so hopefully it will be a quick fix. Thanks for your help everyone.

pinnks - we put the DHW on each evening for an hour because we tend to have a shower in the evening if we've been working on the smallholding, which runs out the hot water in the tank and there's not much left the following morning when DH gets up. We're usually covered in grass/twigs/earth/mud/pig poo/snot/saliva, etc

JKenH

Cottage_Economy wrote: »

pinnks - we put the DHW on each evening for an hour because we tend to have a shower in the evening if we've been working on the smallholding, which runs out the hot water in the tank and there's not much left the following morning when DH gets up. We're usually covered in grass/twigs/earth/mud/pig poo/snot/saliva, etc

I am also surprised you need to boost the tank in the evening. We shower the following morning, frequently before the solar pv kicks in, and we have ample hot water. How much pv does your IBoost ‘save’ to the tank each day?

Cottage_Economy

JKenH wrote: »

I am also surprised you need to boost the tank in the evening. We shower the following morning, frequently before the solar pv kicks in, and we have ample hot water. How much pv does your IBoost ‘save’ to the tank each day?

Just gone to have a look and it appears that our iBuddy has not been recording any savings for some time.

Ok, now I'm wondering how long the immersion has been faulty.

EricMears

Cottage_Economy wrote: »

did the test and put the iBoost on manual boost. Nothing really happened. The water was hand hot coming out of the tap (it should be steaming) and there was no current pulled in from the grid.

Do you have another way of switching the immersion heater on ? Or has whoever fitted the iBoost wired it such that there's no independent way of running it ? If there is an alternative way, that should establish whether the immersion element/thermostat is faulty or if it's the iBoost to blame.