MY BOILER IS TAKING THE P**S

[TURBOTRONICS]

Hi im new on here and don’t know much about plumbing so please be patient with me
Right I have a VOKERA LINEA 24 combi boiler that has been fine for about 5 years but about 12 months ago started playing up when I bled a radiator that didn’t get hot.
After bleeding the radiator and toping the system back up to 1 bar it started to go up to 3 bar and then p**s water out all over the work top.
So I tried draining the system totally then refilled it bleeding every radiator in turn but it still did it.
While the heating was running at 3 bar apart from the water leaking out it was fine till it cooled down then there was no pressure so I had to top it up every day to compensate for this eventually I have had enough and I decided to drop all the water again and I herd that the expansion vessel was probably to blame and sure enough when I checked the pressure in it it was empty but when I tried to pump it up I could here air coming from the bleed valve that I had left open on the kitchen radiator and when I checked to see if there was any pressure in the vessel it was empty.
Right I carnt afford to get it replaced as I believe the boiler has to come of the wall to do this and this is something I carnt do so I thought right shut all radiators fill the system up radiator by radiator until I got to the one that wasn’t working in the first place which I left turned of and I didn’t bleed that one.
The heating now runs grate cold it is at 1 bar and at full heat 1.4/1.5 bar and don’t leek any more.
But when I run the shower after about 5 minuets the water will suddenly go cold and it’s not pleasant for about 30 seconds then worm up again for about 30 seconds and will continue doing this as long as the shower runs.
If I run the hot water top in the kitchen where the boiler is the boiler will run for as above about 5 minuets then just shut of as if I have turned the hat water tap off but there is no funny noises or out then start up again on off on off till I turn the water off.
This is really driving me insane now can any one please shed some light on it for me.
Sorry for such a long post I just wanted to explain as best I can
Ian

 

[Gasguru]

Well it could be something simple such as a temperature sensor but....

topping up with water and refilling the system several times (perhaps without inhibitor) may have caused significant corrosion and blocked the plate heat exchanger.

 

[Tinitus]

When hot tap is running what is the display reading ? also run the hot tap near the boiler and as soon as the burner shuts down close the hot tap quickly and read the display , The difference between the two readings should be about 20 degrees if it alot more than 20 it is deffinately a blocked plate heat exchanger ,

good luck paul

 

[TURBOTRONICS]

Thanks for the replies I will try the temperature thing to see if that’s what it is.
If it is that part what would it entail to fix the issue and would it be expensive to fix.
I only have axes to the net in the day time at work so I will only be able to try it tonight when I get home.
Thanks

 

[TURBOTRONICS]

I have done the test as suggested by pwdavis and have the following results
Boiler shut off at 56oC and when I turned the tap off straight away it went to 91oC
Just before it shut down it was making a slight boiling noise that I haven’t herd before. I take it that the plate heat exchanger is blocked. Is their anything I can do with it or will I have to get someone in to fix it if so will it be expensive to fix?
Cheers Ian

 

[Agile]

If you are clever with mechanical and wet things you could try to remove it and clean or replace it yourself.

On a medium term basis the system needs cleaning or i9t will reoccur again.

Tony

 

[TURBOTRONICS]

what sort of a job would that be. would i have to take the boiler off the wall or can i just remove the part and how do i clean it. this might sound stupid but is their nothing like an auditive that i can introduce to the system that would clean it or prevent this happening again

 

[Tinitus]

Ian
The boiler does not have to come off the wall to change the plate heat exchanger, it is not to difficult to change but if you dont have much experience it could prove to be a nightmare .You could try adding a chemical cleaner to the system but i dont think it would work, but should clean the system to prevent the same thing happening again. after the system has been cleaned it should have an ihibitor added .On your first post you said the expansion vessal needs replacing,but you could also consider adding an additional one elswhere on the system which usually works out cheaper.

good luck
paul

 

[ChrisR]

is their nothing like an auditive that i can introduce to the system

You mean give it a good listening to?

 

[TURBOTRONICS]

i managed to sort the last problem out by fitting an expansion vessel under the bath and changing the heat exchanger and all worked almost fine for a few years
but now its developed another problem
several times iv woke up to a cold house as it overheated in the night
but the other morning it has a different code on the display of 04
when i checked the manual it said the fault was low water pressure but the gage read 1.1 bar
so i had a look at the manual again to find the pressure switch i then took the switch out and taped it up to fool the boiler into thinking the pressure was ok

but now when i run the hot water the burner only runs on low and dosent increase with the flow of water
ie if i run the tap just a little it heats up fine but the more i turn it up the colder it gets oh and when running the hot water the radiators get hot
any advice would be greatfully received

 

[PEDANTICVINDICTIVEMAN]

Press the pin in the middle of the schreider valve on the expansion vessel, if no water comes out then it should be ok, and just needs pumping up to the correct pressure using the the correct procedure.

Getting the DHW plate xchanger out can be a real pain even for the pro's.

Sounds like a suspect diverter now.

 

[scatmanjohn]

i then took the switch out and taped it up to fool the boiler into thinking the pressure was ok

Get yourself a fire extinguisher for when the boiler sets on fire. (seen it happen a few times)

Or even better take the tape of and get the boiler fixed

Sounds like you have a fair bit of corrosion going on.

Your boiler will be dead soon IMHO.

 

[Terrywookfit]

Divertor valve is probably passing due to a stuck spindle.

Usually caused by corrosion within the system.

 

[TURBOTRONICS]

Divertor valve is probably passing due to a stuck spindle.

Usually caused by corrosion within the system.

the valve dose seem to be leaking a little i thought it was coming from the pressure relief valve like it dose
but when i opened the inspection panel to see if i could sort it out its dripping from the divertor valve

 

[Axel]

I once came across a boiler that I thought was taking a pi$$, but it turned out to be the condensate flowing out into the drain.