Descaling Baxi 105e - VIDEO ADDED

[wcavanagh]

Right people, long story and endless crap from British Gas.

Cutting it short. The boiler started making banging and cracking sounds when hot water was run or heating was on. Then few days later hit water was not getting hot enough to wash in.

I live is a very hard water area. So was advised scale was the problem. Changing the DHW Plate Heat Exchanger was advised, I changed this, and hot water was steaming again, great news.

So was advised to de scale the Heating, so on Saturday I drained the system, and gave it a main flush, added a de-scaler that says leave in for upto 1 week. Filled up again to 1.5Bar. Now today it started cracking and banging again when the heating was on, noticed the pressure had got upto 3.5bar.

Can the de-scaler cause this? I poured some of the descaler into the old DHW Heat Exchanger and I could hear it fizzing, so I guess the same must be going on in the boiler. I bled a rad to reduce the pressure it is nor at 2 Bar. What I did notice is while it was banging and crackleing, the pressure needed was jumping in time with the bangs, is this a sign of another problem?

Any help would be great.

Cheers,
Will

 

[45yearsagasman]

What's all the crap from BG about?Did they advise a new plate exch? and a descale of the system.About the only place scale can form to any large degree is in your boiler.As the plate has been replaced then the main heat exch could be a problem.You'll get loads of different ideas on here but if you are contracted to BG why not call them back.Pressure rising to over 3bar may indicate expansion vessel problems.I personally don't like using descaling fluids on these boilers when still connected to the system,it's like using a sledgehammer to crack a nut.Rather track down the faulty part and descale it on its own.

 

[wcavanagh]

Thanks for taking time to reply.

Well they would not cover it under contract as in the small print they do not cover scale, then wanted to charge me £400 + vat to change the DHW heat exchanger, after some research I found it was not in the combustion chamber, and was a case of two screws and 4 new rubber seals, it came to £63 inc, and 20 mins of my time. So BG have been cancelled and I will pay as I go. They were taking the ****, lol.

Would you agree it sounds like a scale problem tho?

Just concerned about the pressure increasing.

 

[lexington]

You normally do not get scale in the central heating flow/return pipework, but in the secondary heat exchanger. Normally sludge builds up in central heating system and this can cause problems in the hot water heat exchanger.
You should have got the radiators and pipework flushed before you installed the new heat exchanger, it has probably blocked it up again. You will need to remove the heat exchanger, clean it out and have the rest powerflushed or at least put on a Tf1 Filter and that will prevent any more harmful particles getting into the boiler.

If the pressure is going up, then that may be another problem, check that you have not left open the filling loop and check that the expansion vessel is still charged.

Regards

Maxgas

 

[wcavanagh]

Thank you for the advice, when I first flushed the system the water was pretty clean, milky in colour and not black.

The banging does not happen when running hot water only when heating gets upto 70c, itbwas prev on both hot water and heating.

I will take each rad off at the weekend and flush in garden to be sure.

How do I check expansion is charged?

Cheers,
Will

 

[PEDANTICVINDICTIVEMAN]

How long did it take to realize BG were taking the ****, 1 year 2 years, more, oh well, better late then never, wonder how many glossy commercials they made with your money.

Hopefully a proper firm or RGI can sort it for you.

 

[wcavanagh]

Had them on contract for a year, never again, I have no problems paying a good plumber, as long as they are not ripping me off like bg were trying. Makes you wonder how many people pay contract and get charged these massive extras prices. I mean £400 for 20mins that is mad.

If a flush does not fix it, I guess I will need to get someone in.

 

[lexington]

To check expansion vessel, first you will need to locate the dust cap, remove the dust cap and quickly press the valve in, if water comes out then the vessel is faulty, as only air should come out. To check the correct charge, you will need a pressure gauge and the system pressure should be at 0 bar when checking. Vessel pressure should be about 1.5 bar.

If it is banging on central heating, more than likely you have a slight blockage in the main heat exchanger or pipework going to it or from it.
I take it you purged the air from the pump after fitting the new hot water heat exchanger?

 

[wcavanagh]

Thank you very much, I will check that in the morning.

Yep I bled all the air from the pump, found a little in the bathroom rad today, but I'm sure system is air free.

Cheers
Will

 

[wcavanagh]

Just done a video of what is going one.

Wondering if anyone has any ideas, I cant get a plumber before Monday, great....

It only starts the noise when it gets upto 60C or so, as soon as the burner goes out, but the pump is still running the noise stops.

Any ideas?

http://www.youtube.com/watch?v=OmwZosLsZMQ&feature=youtube_gdata

Cheers.
Will

 

[wcavanagh]

Well today, while having a shower, the bastard thing went cold, then flashed an error light for the pump......

Im going to rip the thing off the wall and out the window soon, getting very fed up now.

 

[45yearsagasman]

With respect,a plumber will not help you unless he is skilled in boiler repairs and maintenance.It is almost impossible to diagnose these faults without being in front of your boiler.Put your faith in a good boiler repair engineer.

 

[wcavanagh]

Yes, but having trouble finding one.

Like I say best I can do so far is get one next week, and this thing is driving me nuts.

The banging is 100% coming from the top of the combustion chamber, so I am guessing main Heat Exchanger....

Pump is working fine now, wondering if some crap got in it.

Will flush everything tomorrow (got the day off).

Lets see

 

[kevindgas]

pressure is too high, probably air vent not open or blocked, expansion vessel is possibly deflated causing excess pressure.

should be 1 - 1.5 bar cold and rise approx 0.5 - 1bar on heating

 

[petit_pablo]

The sort fault BG could rectify. Maybe you should call them? O **** you cant

Why do people blame the companies (not just BG) when its them that havent read the terms and conditions of the contract they have taken out.