Myson Midas SFI - Hot Water not working

[rhobbs75]

Hi, I'm new to this, but was wondering whether anyone could help me out. We have a Myson Mida SFI and the hot water has stopped working (heating is fine). When you switch the hot water on, its supposed to preheat for 30 secs and the pilot light should come on and then the hot water is available when you turn the tap on, but the pilot light is not coming on. We have had an engineer out three times and they seem to think its the pcb, when they put a new one in, it still didn't work and now they are saying that the new pcb is faulty, so will have to order another one, I'm not convinced that this is the problem (not that I know anything about boilers!), the pcb costs around £330 and I am conscious that we are throwing money at a lost cause.

Has anyone else heard of the same problem and does it sound like the pcb? Is it worth spending this much money on it (plus labour) or should we just buy a new boiler??

Thanks very much

 

[Agile]

I dont think its worth spending that much and I doubt that the part is quite that expensive and probably not faulty either. People who dont understand boilers usually start off by changing a PCB because other parts are usually cheaper.

If you are in Surrey then look up ChrisR in his profile and see if he can come and have a look at it for you. He needs the exercise after the nice meal we had last Tuesday with DP and Alex.

Tony

 

[geoff@cetltd]

Well, if it's not pre-heating, the new pcb could be faulty, but then it's their responsibility, not yours.

There are 6 Status LEDS on the PCB which will give you an indication of what the processor thinks is going on (look in your manual) - do they show a call for DHW when you have a tap on ?

 

[ChrisR]

Selected Product: 470840

Description THORN 4546667 PCB MAIN BOARD
404C656 MIDAS SFI,SI

Retail Price
(Excluding VAT and quantity discounts) £304.32

Coo!

 

[rhobbs75]

Unfortunately we don't have a manual, the boiler is probably about 10 years old and was put in long before we moved in. We have had other problems with it in the past, but it always seemed to sort itself out, apart from this time, I think it probably is the pcb because before the hot water stopped working altogether we were unable to have the heating and the hot water on at the same time. I just don't know whether to give it one last shot with the new pcb or to just go for a new boiler.

 

[ChrisR]

manual is online at partsarena.com/baxi
Check the flow switch & hw pump then the thermistors, which give unusual symptoms iirc.

 

[sparkynotplumber]

My midas si had same problem, the fault was a faulty flow switch which was switching in and out even though the hot water tap was not on, this caused a relay on the board to burn out. I was quoted £200 for the board and another £101 for the flow switch. I un-soldered the relay myself and bought one for £2 from RS, found a replacement flow switch for £30 (online sorry cannot remember company) and It was fine, better than the £1600 I was quoted for a new boiler

Hope some help

Scott