Vaillant e824 Sounds like Aeroplane when Hot water is on ??

[tcullen]

Hi

Can anyone help me ....

Our boiler which is 4 years old is making a noise like an aeroplane passing when you turn the hot water on and now it has all but stopped delivering hot water. This noise fades in and out with each wave of warm water.

The heating side of the boiler is fine.

I'm happy to call an engineer out but it would be really helpful to have a reasonable idea what the problem may be before i do.

Has anyone experienced / solved this before ??

Many thanks

 

[gavinda]

sounds like the heat exchanger is scaled up

 

[gas4you]

Try reverse flushing the main HE with it isolated from the heating system.

 

[gavinda]

wont be the ch side as heating is fine

 

[gas4you]

The vaillants only usually make the awful noise from the main HE when on full power for DHW, even though the ch may work/sound fine.

 

[tcullen]

OK Thanks for all the advice so far ..... following the information in this post I decided to remove and clean the diverter valve. This is how i did it.

1. drained all radiators.
2. Removed mains fuse to isolate the boiler.
3. Drained boiler ( There are additional bleed valve's on the central heating flow far left as you face it and the water in far right as you look at it )
4. Remove divertor valve
5. Clean internal workings using a combination of vinager ( in soak ) cotton buds & an electrical screw driver to scrape the build up off.
6. Refill system.
7. Fuse back in.

That all worked fine and the hot water is fine but i still have the aeroplane noise so i phoned Vaillant at 50p per min !!!!!!

They said the aeroplane noise is caused by air in the boiler ( Cavitation basically ) and the air needs bleeding from the boiler and to call an engineer at £235 !!

Surely I can do this my self but i don't know how as its not in the service manual. Does anyone have a link to instructions or a simple 1, 2, 3 instructions ??

Many thanks

 

[Agile]

Since the boiler made this noise beforee you started to drain it, I dont expect that its air in the system.

As Dave suggests its most likely to be a scaled up main heat exchanger but it could be other causes.

One little test you could do is to run the hot water tap and when it makes the noise turn the tap flow rate down to a third and tell us what happens.

Tony

 

[tcullen]

Thanks for that just tried that and the faster the hot water tap is turned on the louder the noise.

If this is the main heat exchanger which has been replaced before is this a DIY job ? I can obviously get to it easy enough just wondered if i need to interfere with the gas side to change it ?

Thanks

 

[tcullen]

Meant to say would something like Fernox or a silencer help in the short term ??

 

[gas4you]

Reverse flush the HE with the ch isolated, when you think it is clean add X200 before re-filling.

This is very common on Vaillants.

 

[tcullen]

But how do i reverse flush the system ? I assume if it doesn't involve the CH that i don't need to drain it ? A simple 1. 2. 3. and so on would be most helpful.

Thanks

 

[gas4you]

1) Turn off boiler

2) Isolate boiler at ch valves

3) Pressurise to nearly 3 Bar

4) Attach a 1/4 hose to the return drain under the boiler

5) Open drain and run water into a clear bowl

6) Repeat until water is clear.

It may also help to turn the boiler back on and let it run during this process, also turning a hot tap on so the water can run through the plate HE. This can act as a 'sump' for the carp to collect.

It can take quite a while to do this, so don't empty it twice and give up.

Add X200 when finished.

 

[tcullen]

Excellent thanks for that

One last thing do i add the X200 via the heating system ?? ie. the towel rail ? or is there a better way ?

Thanks

 

[gas4you]

No, that will do

 

[tcullen]

Cool I will report back and hopefully conclude this thread tomorrow !!