Question about our new boiler installation

[LeeHamo100]

Hi,

Ill try and keep it simple,

We have had a main combi eco 30 fitted in our house and I have noticed that when i turn the cold tap off suddenly the boiler kicks in and the heating water light flashes for about 1 minute, if i turn cold tap off slowly then it doesnt happen.

Phoned the boiler man and he said he will come and fit a non return valve to the boiler, he said he didnt think there was any dead legs in the system.

Based on what i said about cold tap has there got to be a dead leg to be creating this problem or is there other ways of getting this scenario with boiler kicking in on sudden cold tap turn off?

Is fitting a nrv an easy option for boiler man and is there any drawbacks to having to have one of these put on?

P.S. it does it on all cold taps.


Cheers,

Lee.

 

[Andygasman2010]

Sounds like a dead leg to me. Did you have a cylinder in before? If he's tee'd the hot supply into the nearest one to the boiler and just capped the hot water draw-off in the old airing cupboard that'll be the dead leg.

An NRV would solve it but cutting the dead leg out is best IMHO.

 

[LeeHamo100]

We had a Cylinder before yes, the new boiler is now in that cupboard upstairs instead of on the kitchen wall where it was originally.

 

[PEDANTICVINDICTIVEMAN]

We had a Cylinder before yes, the new boiler is now in that cupboard upstairs instead of on the kitchen wall where it was originally.

So most likely no dead leg, anyway if you think about it "every" tap in the house is a dead leg except when being used.

 

[mickyg]

there might be one thats always been there and would have gone unoticed. Its just unfortunate, and you can't account for it. Nothing wrong with fitting an nrv to get over the problem imo. Especially if its going to be problematic finding it.

 

[LeeHamo100]

Thanks for the reply guys,

I've looked in the cupboard where boiler is and no pipes go up into loft anymore now and all pipes leaving the small cupboard are new so maybe there isn't a dead leg and it is being caused by the fact that all unused taps are dead legs like one person said.

Anyway I was just wondering if fitting a check valve as the installer called it on phone last night was not a good option in the long run or if it had any implications to the system.

I wonder why installers don't just fit them on regardless to save having to maybe go back to a property to fit one.

Cheers,

Lee.

 

[PEDANTICVINDICTIVEMAN]

Because in this world of cut throat business, there isn't the money in a job anymore to fit things which may not be required, if it's a fiver, that makes his quote a fiver more than the next bloke, so believe it or not he may not get the job, some customers are that tight, so it's not going to be fitted unless needed.

 

[Andygasman2010]

quote]if you think about it "every" tap in the house is a dead leg except when being used.[/quote]

Not sure what you mean here, isn't a dead leg just air trapped in the pipe? If a pipe is completely full of water it won't compress and cause any problems. Or am i missing something!

 

[transam]

2" type's of dead leg passive dead leg is were pipe has been capped & air is trapped the op's problem ?? it cause's a delay in the boiler turning off as the presure need's to equalise !

Active dead leg which in theory is the hot pipe from the combi to an outlet , an excessive length of active dead leg waste's water !

 

[onlyfitidealboilers]

Do you have a water meter?

I had this problem on a boiler with an aqua flow sensor, fitted a mini expansion vessel to cold main problem sorted..

 

[LeeHamo100]

We havent got a water meter, we did have a power shower fitted at same time as boiler installation, anyway the man came round yesterday and fitted the NRV or check valve and the problem is solved, so I guess thats it jobs sorted.

Should I be happy?

Is this a good fix?

Who knows.

Im just a perfectionist and dont like workarounds.

Lee.

 

[Gasman77]

It does the job, don't worry about it - life is too short!

 

[gasbanni]

Do the pipes bang at all when the cold taps are shut off quickly ?

If they do a shock arrestor should solve the problem.

simple short vertical pipe that on cold so it will trap air will suffice.

 

[Alfredo]

Do the pipes bang at all when the cold taps are shut off quickly ?

If they do a shock arrestor should solve the problem.

simple short vertical pipe that on cold so it will trap air will suffice.

I was on a Viessman course the other day and their combis have a plastic shock arrester built in. Small vertical tube full of air.

Alfredo

 

[shawd]

Think its page 15 in manufacturers instructions, installer should always fit mini expansion vessel and check valve to stop this fault occuring.