Solar iboost not working

[Mary 12345]

Hi, just seen this thread and my be able to offer some help, shame on the information you have received so far though.

Firstly, what you describe is normal start-up behaviour for an iBoost. When it is first switched on it displays "Low Voltage" (reasonable, there was no voltage) then the software version and then it briefly provides power to the tank to check that that works. Indeed, if you switch an iboost on at night, that is exactly what it does, so it seems unlikely that you have anything wrong with the main iBoost unit.

The symptoms you describe are, however, consistent with the iBoost sender believing that there is no spare power to divert to the immersion heater and this points to the sender unit (or worse). The sender measures the current (power) being fed back into the power grid (exported) and gives that information to the main iBoost controller so that it can adjust the amount of power it sends to the tank, aiming to always export a little.

We know your sender unit is talking to the main iBoost controller so communications are not the problem. So immediate thoughts are:

a) hate to say it, but is your solar system generating as it should be and generating the expected amount (don't know your details so can't be more exact)
b) now check that the thin cable from the send to the current clamp (the square block that clips to your live power feed) is undamaged
c) check that the current clamp is firmly clipped on the right mains input cable. This must be the live feed from either the utility company fuse or isolator switch. The current clamp has a latch on it to be able to fit or remove it and this latch must be firmly closed so the clamp tight right round the relevant cable
d) if the current clamp has been removed for any reason do check that it has been put back on the right way round (yes, it needs to "face" the right way!). If you want a picture of a clamp in position just ask.
d) And if none of these things apply then suspect that the sender has died - but that seems unlikely.
Hope that helps before you run up too many bills.

Thank you for your help. Our solar system is functioning as expected (our electric meter and solar meter are both in the living room, we have created 701kwh since our last feed in statement; one due now and this is In line with what we have made at this time of year in previous years. The electric meter shows red (no power being used from the grid) for most of the day apart from the obvious when kettle or electric oven is on - we have never used huge amounts of electricity as a family so the iboost has always worked well for us until now.... The sender is flashing a green light to indicate working and the clamp is on the right way (had that issue a few years ago when an electrician came to replace our old meter and attached the clamp upside down). The wire from the sender to the clamp seem ok. Could the clamp itself be faulty? With the main iboost unit, we normally leave this switched on permanently via the mains switch, even when we go on holiday as the unit heats the hot water and switches off when hot. When we first noticed a few weeks ago that the water was not very hot despite a sunny day, we did the typical cure used on electronics and turned the iboost off at the power supply, counted to 10 and turned it back on. The iboost then started heating the hot water with the excess power being generated but this then slowly decreased until 0. When the previous replies we were thinking that maybe the power supply from the mains socket to the iboost is faulty / not supplying enough power but have no tools to check this. Do the iboosts have a life expectancy? Ours was installed a few years ago around 2016/2017; I can’t find any paperwork to confirm but I know it was a little while after the solar panels which were put in 2015

 

[Grumpy_Wombat]

OK, well that deals with a lot of the queries. There, is, of course, one other possibility and that is that your tank thermostat (the one in the immersion heater) has become dodgy and the problem is nothing to do with the iBoost at all.. It's easy enough to test this and the wiring to the unit (although I think the wiring is unlikely) at the same time and that is to wait for a reasonably sunny period and put the iBoost into boost mode and leave it for a few hours. Now, that might cost a small amount of electricity if the sun isn't strong enough, but if the tank heats up properly you will have tested both the thermostat and the wiring. And that would leave the unlikely faulty sender or clamp.
In answer to your question about how long should an iboost last. My answer would be more than 5 years and if it failed it would most likely be completely dead. It would, frankly, be that last thing I thought about changing. But then, I've learnt to be surprised. By just about everything.
But just two other questions … how many solar panels do you have and did you say that the iBoost/immersion heater is plugged in using a normal 13A mains socket/plug and not a fixed cable?

 

[Mary 12345]

OK, well that deals with a lot of the queries. There, is, of course, one other possibility and that is that your tank thermostat (the one in the immersion heater) has become dodgy and the problem is nothing to do with the iBoost at all.. It's easy enough to test this and the wiring to the unit (although I think the wiring is unlikely) at the same time and that is to wait for a reasonably sunny period and put the iBoost into boost mode and leave it for a few hours. Now, that might cost a small amount of electricity if the sun isn't strong enough, but if the tank heats up properly you will have tested both the thermostat and the wiring. And that would leave the unlikely faulty sender or clamp.
In answer to your question about how long should an iboost last. My answer would be more than 5 years and if it failed it would most likely be completely dead. It would, frankly, be that last thing I thought about changing. But then, I've learnt to be surprised. By just about everything.
But just two other questions … how many solar panels do you have and did you say that the iBoost/immersion heater is plugged in using a normal 13A mains socket/plug and not a fixed cable?

Yes to 13 amp mains socket and 16 panels

 

[Grumpy_Wombat]

Hmm, I'm surprised at the 13Amp socket, because that is not normal for an immersion heater. Indeed, an immersion heater is close to the maximum a 13A socket can handle and in practice some of the lesser quality plugs and sockets tend to overheat. The immersion heater should be on a separate cable back to your consumer unit (fuse box) and connected by fixed wiring to the iBoost/immersion heater. (For example using a Screwfix 58085). In my opinion this should be looked at by a qualified electrician because there are potential safety issues there.
That said, yes, with 16 panels on a sunny day you will be fine to test the "boost" function to check the tank becomes fully hot without it costing you anything much. And so I would encourage you to do that boost test and see if the tank heats up properly.

 

[marconi]

Dear Mary 12345 with a nod to Grumpy_Wombat :

Lord Finchley tried to mend the Electric Light
Himself. It struck him dead: And serve him right!
It is the business of the wealthy man
To give employment to the artisan.

Hilaire Belloc

My professional advice remains as earlier (public in #11 and private). Stay safe etcetera......

 

[davesparks]

The immersion heater should be on a separate cable back to your consumer unit (fuse box) and connected by fixed wiring to the iBoost/immersion heater. (For example using a Screwfix 58085). In my opinion this should be looked at by a qualified electrician because there are potential safety issues there.

That screwfix item is a switched fused connection unit, this is the wrong thing to use if it is to be connected to a seperate circuit and is not much better than a 1363 plug as it still has a 13A fuse and is rated to only 13A.

 

[Grumpy_Wombat]

Yes, agreed about the chosen part.

I stand by my point that an immersion heater should not be connected to a 13 amp plug-socket combination because it's very near the current limit of a quality part, let alone some that can be found.

It should of course be a 20Amp switch. So agreed about part of the comment.

 

[davesparks]

Yes, agreed about the chosen part.

I stand by my point that an immersion heater should not be connected to a 13 amp plug-socket combination because it's very near the current limit of a quality part, let alone some that can be found.

It should of course be a 20Amp switch. So agreed about part of the comment.

It's is near to, but on the right side of 13A.

I agree it is far from ideal, but it is within the rating of a 1363 plug and socket. I've often done it as a temporary measure.

But this is also powering the immersion heater through an iboost unit, this regulates the power so that it won't always be the full rating of the immersion heater flowing through it.

 

[marconi]

Mary 12345: Davesparks is top of the game in electrical wiring matters so if you have an queries or want confirmation about what needs doing and price following the electrician's visit he is a good contact. I have stitched him up but I am sure he will be chuffed to help.

 

[Grumpy_Wombat]

Indeed. If the 13amp socket is genuinely on a separate supply then theoretically OK as you say (assuming a decent quality one). Since there are 16 solar panels available (some 4Kw max) then the iBoost might be at full power for a number of hours.

My concern would be that the 13A socket is part of a ring and not a separate connect …. and there's no easy way of determining that sight unseen.

Not that this diversions helps resolve the initial issue of it not taking current anyway …...

 

[Mary 12345]

I have now checked the emersion heater via the iboost on boost and it heated the water tank up fine so all working. Now thinking it must be the sender or clamp (which is definitely the right way up). Everything seems to indicate that the iboost is receiving from the sender but it must be sending a there is not enough excess energy (even when there is) permanent message. Any ideas on if it’s more likely to be the clamp or the sender unit itself?

 

[marconi]

Mary 12345: Because it is no cost and easy to do as a test - please reverse the direction of the clamp and see what happens. Be careful to keep your fingers away from the ends of the power cable and have an attendant. Turn the electricity off while you do it. You will need some sun electricity of course to see if the iBoost starts to work.

If it makes no difference then restore the direction to how it was.

 

[Grumpy_Wombat]

Changing the direction won't hurt, although it was clearly stated that it was the right way round, having been replaced the wrong way round some time ago.

Given that the tests seem to have eliminated every other possibility then it does seem to be that the fault in the sender (or the iBoost) itself. Probably the best way is to buy a replacement sender clamp and sender from Marlec and try those in various combinations. (They do accept returns less postage if you find that that the new parts don't fix it).

And, of course, in the meantime, bear in mind that you can press the boost button on sunny days without incurring electricity costs.

 

[marconi]

Mary 12345: I recommend you don't spend any money on a new sender or new clamp yet. The fault I reckon is in the iBoost. Pressing the Boost button temporarily circumvents the power electronics of the iBoost using a relay ( a switch) which connects the immersion heater directly to the mains - you have confirmed already this functionality is working.

It is probable - in my view - that the power control electronics for the iBoost functionality have failed. The iBoost power control electronics uses a semiconductor switch not a mechanical one like a relay because it can be turned on/off very quickly. By varying the ratio of on to off time the iBoost ensures as much average power flows to the immersion element as is being exported from your PV system. If this semiconductor switch - a triac- stops working or whatever controls its on/off, then no power will flow to the immersion heater irrespective of whether there is excess PV power being exported.

You have had a good offer from Marlec to test your device at #11.

 

[Grumpy_Wombat]

All depends which is better for you. Post #11 indicates that they are not accepting returns at the moment although that might change soon. And, of course it has to be safely disconnected. However, If you assume that it is the main unit that is faulty then this is the correct course of action. At least we've moved on from a flat standby battery.

If, however, eliminating any sender problems sounds useful, the downside is the return postage and the time taken. Always assuming that Marlec are open enough to ship spares.

Unfortunately, there's no one good definitive answer at this stage and I regret I can't give you one.