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Hi there, I have a vaillant turbo max 28e combi boiler. The…

Hi there, I have a...

Hi there, I have a vaillant turbo max 28e combi boiler.

The Dhw will not get sufficiently hot and will cut in and out intermitently. The central heating appears unaffected when it is either on or off.

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Answered in 17 hours by:

10/12/2012

Plumber: Michelle-Mod, Moderator replied 10 years ago

Michelle-Mod, Moderator

Category: UK Plumbing

Satisfied Customers: 21

Experience: Moderator

Verified

Hello,

I'm a moderator for this topic. I've been working hard to find a Professional to assist you with your combi boiler, but sometimes finding the right Professional can take a little longer than expected.

I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.

Thank you!

^Michelle

Plumber: Andrew Smith, Engineer replied 10 years ago

Andrew Smith, Engineer

Category: UK Plumbing

Satisfied Customers: 4,029

Experience: Domestic Gas, Commercial Gas, LPG, Unvented Hot Water, Part P Electrical, Commercial Catering

Verified

Hi my name is XXXXX XXXXX lets see if we can get you sorted in the shortest possible time. Can you let me know how old your boiler is, it sounds like you have a scaled up plate heat exchanger?

Customer reply replied 10 years ago

Hello Andrew,

Thanks for getting back to me.

I would still like your assistance and am happy to discus further with you.

I can't be certain but it is around 10 to 12 years old.

I have used this service before so am familiar with the process. It is probably best to find a time and day that we can both be online to have a real time discussion so I can carry out any checks or testing for you.

Can I suggest tomorrow afternoon (Sunday)

Plumber: Andrew Smith, Engineer replied 10 years ago

No problem - just come back when you are ready.

Customer reply replied 10 years ago

Hello Andrew,

Are you available to start investigating the problem.

Will wait for you reply.

Terry

Plumber: Andrew Smith, Engineer replied 10 years ago

Ok, when you run the water does the boiler start immediately?

Customer reply replied 10 years ago

Yes, all light start in sequence according to manual and boiler fires up

Plumber: Andrew Smith, Engineer replied 10 years ago

If you run your tap quite fast do the burners stay at maximum?

Customer reply replied 10 years ago

No, with just dhw on (no ch) the boiler fires up then the water gets warm then after 10 seconds it cuts out. And refires after 5 secs or so. It continues to cycle like this as long as the tap is running but water never gets hot. The water pressure also seems to increase and decrease (only slightly) as the boiler cycles

Plumber: Andrew Smith, Engineer replied 10 years ago

It sounds like the plate heat exchanger is scaled up.
This would mean that there would be poor heat transfer and the water out of the tap will only be warm, also the boiler would cycle because it is firing to heat the water but because it cannot get rid of the heat into the water it will turn off because it has reached temperature, then it will cool and fire up again.

Are you able to strip it out and descale it?

Customer reply replied 10 years ago

Yes, I am able to do it,
Although what is the best way to de-scale it? Would this solve it or be a temporary measure?

Plumber: Andrew Smith, Engineer replied 10 years ago

It is a permanent measure, but you will have to do this every so often to keep on top of it.
Take it out and place it in a strong dose of descaler and let it fizz for a good 10 minutes - it will eat away all the limescale.

Andrew Smith, Engineer

Category: UK Plumbing

Satisfied Customers: 4,029

Experience: Domestic Gas, Commercial Gas, LPG, Unvented Hot Water, Part P Electrical, Commercial Catering

Verified

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