Noise from Boiler and pressure fluctuation

[nickem09]

I have a Potterton Promax combi HE Plus, which is about Three years old.

The central heating appears to be fine, however when I run the hot water I get a a horrible knocking/banging sound from inside the boiler and the pressure fluctuates between 1 and 1.5 bar, the noise stops as soon as the hot water tap/shower is turned off and the pressure immediately stabilises. This does not happen all the time I would say about 1/3.

My questions:
Is this likely to be an air lock, if so how can I remove it from the system?
Could my pump be at fault, should I call an engineer?


http://www.youtube.com/watch?v=tyPWUU2DVdk

 

[Agile]

Original help deleted as a result of the OP's unthankful attitude!

Tony

 

[nickem09]

Thanks for the quick reply if it is the plate can this be cleaned or does it have to be replaced?

Also is this something that has to be done by a heating engineer, any idea on the expected cost of part and replacement?

Regards,

 

[Agile]

Original help deleted as a result of the OP's unthankful attitude!

Tony

 

[nickem09]

Is there any other information I could give that would be helpful in this case?
I did have a hot shower this morning with only one incident of cold then back to hot, no noise this time from the boiler also ran hot water last night without any issues, but I guess these things don't fix themselves, did you view the utube video of the noise and fluctuation from by first post?

Kind Regards

 

[wcavanagh]

Not sure if it helps, but I had exactly the same issues with a Baxi, and it was a partial block in heat exchanger, chap fitted a new one, now it is silent.

Good luck with it.

 

[Agile]

I did not view the video.

As I am not coming to your boiler its not very relevant and merely listening to it is not likely to help me anyway.

As with all boiler faults there are several possibilities to be considered by an engineer using diagnostic skills which do not include guesses!

Tony

 

[nickem09]

I could do without the negative tone.
I was just trying to help resolve this matter as I know nothing about heating or boilers...sorry for wasting your time.

 

[Agile]

I help a lot with people who have heating problems giving my time and skills free of charge.

But I do not take kindly to anyone who does not appreciate me trying to help them!

My recommendation is that you keep your ungratefulness for parking wardens and the like who are more deserving!

 

[mysteryman]

Tony always likes to sound as if he is smart.

The problem could be sludge in the boiler from a dirty heating old system - which should have been powerflushed before the new boiler went on the wall, or it could be a sticking diverter valve, sometimes caused by the same dirt.

You should get the boiler powerfushed, and then the whole heating system powerflushed, opening up the radiators one at a time so that you know they've all been cleaned.

I could be completely wrong, of course, but in my professional opinion, there is little point in replacing a plate heat exchanger that is sludged. If it is sludged, so will other parts of the boiler be, on the primary circuit within the boiler. You can still get central heating sometimes in these circumstances.

 

[nickem09]

Thanks to everyone on DIYnot who has given help and advise on this matter. Its not easy trying to get to the bottom of a problem that you know nothing about, trying to explain the problem under these circumstances is difficult. Fortunately there are experts out their who can answer questions and give their opinion without making the non-expert feel stupid and uncomfortable. As for removing helpful posts, that's just childish and petty.

 

[Agile]

If you did find my replies helpful then I would have expected that you would have thanked me rather than accusing me of negative tones.

You have to understand that I spend some of my time to try to help people and sometines thats a thankless task.

 

[DP]

Nickem09, don't lose any sleep over Tony's attitude. He indeed is a clever fellow but has a VERY big drum to beat too. He still lives in a school playground early hours of the mornings.

The problem is sediment/ dirt related. If you are mechanically minded, you could introduce some cleansing chemicals into the system and follow the maker's instructions. Sounds as if the system was not cleaned when new boiler was fitted which, sadly is very common. You could call the fitter who installed the boiler and have a word with him.

Visualise a pot of soup that is not stirred when it is being cooked. Burner will burn the broth that is in contact with metal base. Meanwhile body of the broth is not getting the heat as the burnt 'sediment' is getting thicker. Similarly visualising a heat exchanger, sediment in a heating system will coat the heat exchanger with a layer of dirt. Fire on the other side of the metal heats the water in the sediment which turns to steam resulting in pressure fluctuating. You could have circulation problems too in which case you will need someone like Tony, without the accompaning bullsh1te, to diagnose and fix the problem. Also, water that is heated in the heat exchanger, needs to be removed double quick or temperature will quickly reach boiling point, again resulting in a dancing pressure gauge

 

[nickem09]

Thanks for the detailed response its much appreciated. I will be calling an Engineer ASAP. Keep up the good work.

Kind Regards,

Nick

 

[nickem09]

If you did find my replies helpful then I would have expected that you would have thanked me rather than accusing me of negative tones.

You have to understand that I spend some of my time to try to help people and sometines thats a thankless task.

I understand that you may have got frustrated with my poor failure descriptions, sorry for that and I do thank you for your time and posts. Please accept my apologies in this matter.

Kind Regards,