Boiler turning on with cold tap usage

[Nathanlowe25]

We are getting our loft converted and plumbers have been in to fit pipes that go up into the loft and I have noticed the following happening since:

Boiler turning on when cold tap is used. (This doesn't always happen, its infrequent).

Boiler - Vaillant ecoTEC plus 824 R1

Symbols appearing:
Flame - Burner On
Circle - Internal Loop is Running
Timer - Gas valve is activated

Annoyingly the plumbers have just been back round to look and it isn't happening but it did last night when I flagged to the loft company owner.

Thanks,

Nathan

 

[Jurassicspark]

Could be air in pipes..
Have you got mixers?

 

[terryplumb]

Dead leg in pipework possibly.

 

[gas112]

Is it the burner actually firing up and staying on for a while or just momentary bringing pump and fan on

 

[Deleted member 294929]

Needs a shock absorber or a mini expansion vessel?

 

[Nathanlowe25]

Could be air in pipes..
Have you got mixers?

No idea what mixers are or how to find out.

 

[Nathanlowe25]

Is it the burner actually firing up and staying on for a while or just momentary bringing pump and fan on

It’s just momentary.

Run the cold, turn it off, then it fires up for a few seconds and the symbols in my above post come on then go off.

I don’t recall this happening until the plumbers did pipe work to go up into the loft so wondering what has changed and what needs doing.

 

[gas112]

It’s just momentary.

Run the cold, turn it off, then it fires up for a few seconds and the symbols in my above post come on then go off.

I don’t recall this happening until the plumbers did pipe work to go up into the loft so wondering what has changed and what needs doing.

If they have just extended pipework without any other alteration then its possibly just some trapped air in a leg , if they have altered it then its probably a dead leg and as bod says shock arrestor should stop it

 

[Deleted member 267285]

No idea what mixers are or how to find out.

The type of taps - separate hot and cold or a single tap (monobloc) or a deck mixer that mixes the hot and cold. If you have a dead leg in the system get it removed rather than fitting a shock arrestor

 

[Nathanlowe25]

If they have just extended pipework without any other alteration then its possibly just some trapped air in a leg , if they have altered it then its probably a dead leg and as bod says shock arrestor should stop it

As far as I am aware they have just extended the pipe work up into the loft.

Would bleeding the radiators resolve it ?

 

[Nathanlowe25]

The type of taps - separate hot and cold or a single tap (monobloc) or a deck mixer that mixes the hot and cold. If you have a dead leg in the system get it removed rather than fitting a shock arrestor

This has been fitted in the loft but not used yet as bathroom suite isn’t in.

Merano Avellino Dual Head Thermostatic Concealed Mixer Shower - Brushed Brass

Merano Avellino Dual Head Cool Touch Thermostatic Concealed Mixer Shower - Brushed Brass. Internet Only Price. In stock: Delivery Next Day.

www.plumbworld.co.uk

 

[gas112]

As far as I am aware they have just extended the pipe work up into the loft.

Would bleeding the radiators resolve it ?

no its in the actual pipework to taps etc not the rads could well be air in new shower supply pipes run shower into a bucket for a bit to clear any air

 

[Nathanlowe25]

no its in the actual pipework to taps etc not the rads could well be air in new shower supply pipes run shower into a bucket for a bit to clear any air

If this is the issue / resolution. Would it resolve itself when everything is installed and I can turn the taps / shower on?

 

[Jurassicspark]

Would it resolve itself when everything is installed and I can turn the taps / shower on?

Yes. Just cross your fingers.

 

[Nathanlowe25]

According to Vaillant the code that runs on my boiler after cold water tap used is “pump overrun following a hot water demand”