Solar iboost system - being charged for 'free' hot water

paul991

wonder if your  immersion is heating up at times other than when pv is producing ,I have a different make with a boast function .Its worth putting a picture of your wiring on here it could be as simple as a CT clamp being on the wrong cable or facing the wrong way . Have you a indicator ,Neon on your switch. 

Heedtheadvice

As usual trying to diagnose problems from afar without quite  a bit of information is not easy and can be a bit hit and miss. In this case we ( and you ) do not know if the system was ever installed properly or if it was ever working properly or has developed a fault.

Can I suggest that it might be a sensible way forward for you to go through logical troubleshooting as far as you are able and post back the results you find. Marlec's web site guide is at https://www.marlec.co.uk/troubleshootmysolariboost/ .

Hopefully that will help to answer some basic questions. You could also post pictures  of the results and meter indications especially if understanding  them is not easy. Bear in mind that your PV Solar output can be quite variable especially as clouds pass so it could be useful to switch it off during the trouble shooting to remove one variable! Similarly house power consumption can vary so best try and reduce  that during testing but the trouble shooting will specifically ask you to draw some power at points in the testing process ( such as filling and switching on a 3kW kettle ).

It should be quite easy to do and even if it does not solve the problem should help posters to guide you further.

Reggieboy2025

Martyn1981 said:

Reggieboy2025 said:

I have a PV generation meter that flashes red when it's generating power from the panels , it's connected to the CU  
Will try to include pictures 

Thanks Reggie. If the PV is going through the CU then it should be displacing some or all import. That really is strange, no wonder you are baffled. Please keep us updated as I'm sure (like me) we are all interested to know what is going wrong.

Edit - Sorry, one last question (now I sound like Columbo), when the PV was originally installed, did you notice a reduction in your leccy consumption and bill?

I've noticed a slight reduction in my bills probably get a better idea after a couple of months with the new meter?

Qyburn

Photos and a bit of digging to check wiring is needed. With a 3kW house load it's simply impossible for the cable to be both carrying "spare energy" and also be importing 3kW. 

Reggieboy2025

Qyburn said:

Photos and a bit of digging to check wiring is needed. With a 3kW house load it's simply impossible for the cable to be both carrying "spare energy" and also be importing 3kW. 

When the PV array is providing say 1.5kwatt then the solar iboost imports the rest from the grid to make the Kwatts up to 2.9ish.
If the PV array is providing 500 Watts spare the solar iboost imports the rest from the grid to make up 2.9 ish .
The immersion never heats the water with any less than 2.9/3Kwatts regardless of what spare PV energy is available.

Thanks again guys

Martyn1981

Reggieboy2025 said:

Qyburn said:

Photos and a bit of digging to check wiring is needed. With a 3kW house load it's simply impossible for the cable to be both carrying "spare energy" and also be importing 3kW. 

When the PV array is providing say 1.5kwatt then the solar iboost imports the rest from the grid to make the Kwatts up to 2.9ish.
If the PV array is providing 500 Watts spare the solar iboost imports the rest from the grid to make up 2.9 ish .
The immersion never heats the water with any less than 2.9/3Kwatts regardless of what spare PV energy is available.

Thanks again guys

Ahhhh, that makes much more sense. So the PV is contributing, but the iboost isn't limiting energy to the level of excess (export), but instead running at full power.

I'm going to guess that that is simply due to the iboost being faulty, or set up wrong.

Heedtheadvice

Hence why I suggested the trouble shooting ...

Qyburn

Reggieboy2025 said:

...
Yeah it always rises to more or less 3 Kwatt regardless of the spare energy being produced by the solar panels.
The inverter can display 1kwatt being produced and with nothing else on in the house the meter is using 3kw .

What you've said just now makes more sense than your original description, above.

It sounds like it's switching on when there's some spare energy, but always switching on to full power instead of varying power to match.  The online manual that I found doesn't seem to show this as an option, suggesting that yours may be faulty. Do you have the manual for your exact model?

Heedtheadvice

Yes it could well be  a fault with the iboost but also a 'manual' boost- which I believe is possible with the unit. The actual problem description  leaves that probably open to interpretation.

Just doing that manufacturers troubleshooting actions should quickly and easy clarify if there is  a problem and if so where it lies.

The latest manual is at https://www.marlec.co.uk/wp-content/uploads/2016/01/Solar-iBoost-User-Manual-111215.pdf?v=6805cdfd0c7a.

It could be something as simple as the measurement  clamp  being in the wrong location!

Reggieboy2025

Had an electrician visit , assures me clamp is in correct position, the iboost system is designed to deliver variable power to the immersion as per PV generation but the Kwatts are always around 3.
Have reached out to Marlec about the problem , they've no idea either

Many thanks guys