viessmann vitodens 100w hot water issue

[Robert Kondrat]

Hi Guys,

New to the forum and absolute rookie so please have a mercy 🙂

I have a combi Viessmann vitodens 100w which does not give the hot water constantly, we have moved in to the house 6 months ago and when during the summer months it's not a big issue, during the winter it would be nice to have a constant hot water in the shower. By constant I mean at the moment when you open a shower (or any hot water tap for that matter) you'll get the hot water then it goes to lukewarm and coldish and then it gets hot again and this goes on and on and there is no constant hot water coming out regardless to however I set the dial on the boiler and turn the comfort mode as well. Is this an issue with the boiler not being efficient enough in heating the water or it can be some kind of a fault or wrongly set up boiler issue? I have no idea who installed it, as I said we moved in 6 months ago. Appreciate any suggestions/answers.
Thanks!

 

[Riley]

You will need a gas safe engineer my friend nothing you can fix

 

[ShaunCorbs]

Hard water area ?

 

[townfanjon]

2 things may be going on here

Is the tap symbol constant on screen, or going on and off .
The other one is a blockage , sorry I cant be specific we do not endorse you opening up your boiler.

 

[Robert Kondrat]

Hi Thanks for your replies. I will check the tap symbol on the screen if it stays constant on the screen.
Appreciate the help.

 

[Robert Kondrat]

Hi I've checked, and the tap symbol stays all the time when the hot water is on, the burner symbol however does disappear once the temp on the screen reaches 90+ and once temp goes down to 50+ (the water gets lukewarm now) it appears again, and shortly after that there is again a hot water coming out of the tap. I have also noticed that once I switch to comfort mode it never stay in that longer then a day, if I set it in the afternoon, in the morning next day is on ECO again.
Appreciate the feedback.
Thanks.

 

[townfanjon]

The eco/ comfort thing is a bit weird on them , it sounds like you have a blockage , its an easy fix but it points that your system is sludged up so you probably need a flush and a filter or it will happen again .

 

[Robert Kondrat]

Hiya thanks for your reply. I have posted the job on rated people and got someone coming back to me with quote of £285 saying he can fix it, but did not went in to detail what actually needs fixing, so I'm bit reserved at the moment. I don't suppose with that little detail you could say if it's right price for the job..Just going to have to wait and see if other quotes come in. Thanks again for all replies.

 

[ShaunCorbs]

Have you asked the manufacturer?

Fixed price repair

 

[Robert Kondrat]

I haven't no. Do you think it's wort going to manufacturer first?

 

[ShaunCorbs]

I haven't no. Do you think it's wort going to manufacturer first?

Well I think there fixed price repair is around the 250 mark

 

[Robert Kondrat]

Well I think there fixed price repair is around the 250 mark

Good to know I'll give them a ring. Thanks.

 

[Robert Kondrat]

Hiya been on the phone with veissmann tech help and they have also suggested that this may be caused by blockage. They do not send out engineers but asked me to find local installer through their website which I will do and ask for quotes. Thanks for the help so far.

 

[John Coyne]

Hiya been on the phone with veissmann tech help and they have also suggested that this may be caused by blockage. They do not send out engineers but asked me to find local installer through their website which I will do and ask for quotes. Thanks for the help so far.

We have the same problem with that boiler. Replacing the plate heat exchanger didn't fix it for us. Did you manage to resolve the problem?
Thanks.

 

[John.g]

So its still got the same problem of running hot then cold like the 3 year old problem above?
Can you run the water flow from a hot tap only into a dish for 30 secs, then measure this and double it to give you the HW flow in LPM.