Combi Boiler Comes On Briefly As Cold Water Is Run

[baxpoti]

Only if your name is Baxpoti obviously.

Any installer worth his salts will make sure to remove them and not find a work around for it!

Stan

Lost me there Stan. Only what?

I never mentioned dead legs.

 

[Gasguru]

A sign of trapped air is to look at the flow from the taps as you initially open them - often the flow is a little higher for the first second or so after opening as the pressure is boosted by the compressed trapped air.

Check all hot outlets for trapped air - perhaps you have a hot feed to the washing machine but it is not being used (ie washing machine only required a cold feed).

 

[pbar]

Thanks as always for your replies and advice.
Yes, both my hot and cold taps upstairs have a higher water flow for a few seconds when they are turned on, then they calm down shortly after.
We changed the washing machine several years ago for one that only needed a cold water supply, and the hot was capped off and hasn't been used since.
My plumber is back tomorrow fitting a check valve to the cold water in on the boiler. Hoping that will fix the problem perhaps?

 

[Gasguru]

Perhaps you have a hot feed to the washing machine but it is not being used (ie washing machine only required a cold feed).

We changed the washing machine several years ago for one that only needed a cold water supply, and the hot was capped off and hasn't been used since.

Therfore remove the cap and let the air out.

 

[baxpoti]

My plumber is back tomorrow fitting a check valve to the cold water in on the boiler. Hoping that will fix the problem perhaps?

He'll need to fit a mini expansion vessel as previously advised

 

[ChrisR]

If that's so, how come trapped air in the capped off pipes (which used to run to the boiler in it's old location) is causing the problem

AIR IN THOSE PIPES WOULD BE IRRELEVANT, SO THEY ARE NOT RESPONSIBLE!

Jeez. Just fully open One at a time each of your cold, and hot water outlets, including the ones which in your opinion don't matter.....
Do it every couple of days until all the air is out.

 

[pbar]

My plumber is back tomorrow fitting a check valve to the cold water in on the boiler. Hoping that will fix the problem perhaps?

He'll need to fit a mini expansion vessel as previously advised

My plumber reckons this is not needed as the combi boiler has one built in.

 

[pbar]

If that's so, how come trapped air in the capped off pipes (which used to run to the boiler in it's old location) is causing the problem

AIR IN THOSE PIPES WOULD BE IRRELEVANT, SO THEY ARE NOT RESPONSIBLE!

Jeez. Just fully open One at a time each of your cold, and hot water outlets, including the ones which in your opinion don't matter.....
Do it every couple of days until all the air is out.

That's impossible as the old pipes been permanently capped off.

 

[pbar]

Perhaps you have a hot feed to the washing machine but it is not being used (ie washing machine only required a cold feed).

We changed the washing machine several years ago for one that only needed a cold water supply, and the hot was capped off and hasn't been used since.

Therfore remove the cap and let the air out.

And be flooded with water too!

 

[Paul Barker]

Bleed it and put the cap back.

 

[pbar]

My plumber is back tomorrow fitting a check valve to the cold water in on the boiler. Hoping that will fix the problem perhaps?

He'll need to fit a mini expansion vessel as previously advised

My plumber is saying that this is not needed as combi boilers have one built in. Can anyone confirm this please.

 

[ChrisR]

That's impossible as the old pipes been permanently capped off.

Don't be ridivulous of course it isn't impossible. Caps can be removed.
Or live with the problem.

He'll need to fit a mini expansion vessel as previously advised


My plumber is saying that this is not needed as combi boilers have one built in. Can anyone confirm this please.

Don't you think one of us would have advised you of this if it were true?

Your plumber's ignorant.
Maybe you have trouble finding one who will put up with you?

 

[pbar]

He'll need to fit a mini expansion vessel as previously advised


My plumber is saying that this is not needed as combi boilers have one built in. Can anyone confirm this please.

Don't you think one of us would have advised you of this if it were true?

Your plumber's ignorant.
Maybe you have trouble finding one who will put up with you?

I was thinking perhaps the gentleman who advised to fit the mini expansion vessel might not have been aware that it is a combi boiler, especially with me having conflicting advice (yes it's needed, no it isn't).

Please refrain from personal attacks and agression, I simply have little plumbing experience and am asking for advice, if you are unable to post in a civilised manner, please do not do so.

Please can someone confirm if my plumber is correct or not, I have a Worcester 240 combi boiler, and he is fitting a non return valve to the cold water in to stop the boiler activating when cold water is run. Does he need to fit a mini expansion vessel, as he says he should not. Thank you.

 

[gas man patt]

HI, AS FAR AS I KNOW THE WORCESTER 240 DOESN`T HAVE AN INTERNAL EXPANSION VESSEL ON THE COLD MAINS SIDE, IT DOES HOWEVER HAVE ONE FOR THE CENTRAL HEATING. BE WARY OF FITTING NON RETURN VALVES WITHOUT A MINI EXPANSION VESSEL AS THIS COULD CAUSE A PRESSURE BUILD UP IN THE BOILER, ESPECIALLY IF YOU ARE ON A WATER METER, INCIDENTLY HAVE YOU RECENTLY HAD A METER FITTED? THIS INCORPORATES A NON RETURN VALVE. IT MAY WELL BE THAT THE MAIN WAS ABSORBING THE PRESSURE BEFORE AND NOW IT CAN`T ??

 

[Agile]

I was thinking perhaps the gentleman who advised to fit the mini expansion vessel might not have been aware that it is a combi boiler, especially with me having conflicting advice (yes it's needed, no it isn't).

Please can someone confirm if my plumber is correct or not, I have a Worcester 240 combi boiler, and he is fitting a non return valve to the cold water in to stop the boiler activating when cold water is run. Does he need to fit a mini expansion vessel, as he says he should not. Thank you.

I can assure you that everyone ( except you ) who has posted anything on this thread will have been totally clear that it is a combi boiler.

I am sorry that you have been unable to assimilate the posting I left but I will repeat the salient point!

A mini EXV WILL be needed if the non return is on the input to the boiler!

A mini EXV will NOT be needed if the non return is on the outlet from the boiler.

If it were left out then it is unlikely to cause a problem but its not correct !!!

Tony