Review Time
I was very much enjoying my Mixergy tank and it had become an important part of our zero bills home. Simply knowing how much water you have means you never heat more than you need.
However... the controller board broke 3 months out of warranty, predictably on Christmas day. Reverse engineering it showed that the main heater switching relay had destroyed its drive circuitry - snubber diode D14 failed short circuit which then blew up the drive transistor Q4 which has then taken out the control line coming from the microcontroller. That was a pity as the whilst the diode and transistor would be replaceable the microcontroller isn't as it will be running custom software. The snubber diode does not seem to be specified to handle the back EMF from the relay so this is probably going to happen to other tanks. Mixergy wouldn't replace the board as its out of warranty even though this is a design issue in my eyes. They told me a new one was £700. That annoyed me as I really can't see that the sum total of the parts and manufacturing on the board goes to more than £75. It's either designed badly or its designed to fail neither of which is great. I'd expect a hot water tank to last 25 years and I'd expect spares to be reasonably priced - I've already paid extra for a "smart" tank. I'm not going to carry on paying £700 every 3 years - that wipes out any savings from the clever control features.
I sent them an email grumbling about it but I never got a response.
When this happens to yours and you are trawling the internet looking for a solution, there is a work around that you can to do - the aux relay appears to share the same drive logic as the main heater relay. So long as that hasn't blow up its channel of the microcontroller already, you can move the main heater over onto that and it will work in the same way. I may get some more years out of it like that and when that fails I'll build a relay connected to Home Assistant to control it. The most useful feature of it for me is the state of charge reporting - so long as that's still running I can control it.
----------------
Edit in response to mixergy reply. I don't really acept that a solid state diode is subject to wear over time. It would be subject to gradual degredation if opperated oustside it's specifications though: this is a design issue.
I'd be happier to accept that a piece of tech that costs £75 to make might fail after a few years if the replacement for it was also £75. If one dies every 3 years then I need 8 over the life of the tank - at £700 each that's another £5600 on top of the cost of the tank to keep it running - I might as well just get a dumb tank with an immersion heater and a timer in it.
The tank itself when working is great. However the customer service when reporting the tank not heating has been abysmal, and that’s being polite. Tank been out of action since Saturday 20th of February and unable to contact Mixergy over the weekend. Spoke to customer services three times during the week and am now going into the second weekend still with no hot water. There has been absolutely no desire or attempt to call me back to offer a resolution or support. Quite shocking really. Have faith in the product but no faith whatsoever in the customer service. Really poor.
Been appalling from the minute I moved in to my new home. Tried to speak to the builders about the hot water not heating up and when it does I only get 20%. *** UPDATE***I spoke to one of the engineers today and they came out same day within a matter of hours and sorted the issue. It took him less than 10 minutes. Abbas also showed me a few tricks with the tank to make sure I always have hot water too in case of an emergency.
Im giving two stars as when the tank works its great. Customer service alone would be one. Our tank has failed. Only source of hot water two young children in the house. Reported fault Thursday, Friday no further to help and closed over the weekend. Very dissapointed customer with a compeltely non functioning 1 month old expensive tank. They are apparently too understaffed to help!
Whilst it was a little disappointing that our iHP X cylinder broke down after just over a year's use, requiring a new control board, the repair experience was excellent. From phone support given on Boxing Day to Danny attending and fixing the boiler a couple of weeks later (we had some hot water all along via the immersion element), it was a very good service experience
Claim your business profile now and gain access to all features and respond to customer reviews.
Mixergy are the UK's market leading smart hot water tank company. Our cylinders 'heat what you need' making them 5x faster, 30% smaller and up to 40% cheaper to operate. Each cylinder is controlled via an app allowing optimum control and machine learning (ML) schedules ensure that you never run out of hot water!
