Heatline Vizo - DHW Fault

[NRudd]

Hi, can anyone help diagnose a fault with a Heatline Vizo? A few months back I noticed after running hot water that the DHW led would flash on the boiler, this resulted in us having to run the hot water tap slowly in order to get hot water until finally it became hard to get lukewarm water. At first I thought the heat exchanger may be blocked so this weekend I replaced the HE with a new one and for the first 20 minutes the boiler ran with no faults and we had hot water but this was short lived and now we have the same fault and having to reduce the flow from the tap to get hot water. I've uploaded a short video clip of the fault that I took using my phone.

Heatline Vizo - DHW Fault

• NRudd
• 26 Feb 2019

A DHW fault on a Heatline Vizo boiler

 

[Gasguru]

Check the DHW thermistor.

 

[ianmcd]

+1 for dhw thermistor

 

[NRudd]

Thanks for a quick response, and sorry to hassle you again (the documentation for this boiler is horrendous), can either of you shed any light on what bit is the thermistor, or what it's referred to in the documentation. I've taken a few photos if that helps.

 

[Gasguru]

You've found it..the white bit screwed into the brassware just above the hot outlet, unclip the diverter motor head to give access.

 

[ianmcd]

Dont worry if the replacement is a different colour, they are all the same but depending on manufacturer can be different coulors the part number is 3003200031 the same thermistor is used on many boilers

 

[NRudd]

Thanks guys for all your help, I'll get that part ordered and look to get it replaced in the next few days. Many thanks for your help so far, very much appreciated.

 

[NRudd]

Thank you to you both, the new thermistor arrived today and I've successfully replaced it and so far so good, the boiler is working with no warning lights .