heat line vizo problem

[mattysupra]

hi all, my boiler has started to go hot and cold when in the shower. The boiler has a temperature gauge on the front (line of LED's) and when it gets just 2 of the 7 LED's lit up the boiler turns off for maybe 5 seconds then reignites. I have tried turning the water temperature up and down but this seems to just change the flame hight and will still only get to the point of lighting two LED's up.

However if running the central heating it will light all the LED's up and sitting there working fine, just hot water seems to be the problem.

Any ideas?

 

[mickyg]

most likely:
blocked plate HE.

 

[mattysupra]

whats a blocked plate? There is loads of flow through it. Getting 2 bar of water pressure out the shower head.

 

[mattysupra]

o.k been having a look around and think a blocked plate means blocked heat exchanger? Would i still get good flow if this was blocked? also the system was power flushed and inhibitor put in october last year after a fault with the divertor valve. Yes it was full of ****! I made a mistake of paying the plummer who installed it in full before he had finished and could never get him to come back and finish of installing it properly (was missing earth bonding and the over flow pipe was not connected plus it never got flushed before it failed last october)

I have since had these things sorted out at my cost.

Any help please on how or what needs doing, or a good installer in birmingham?

 

[mattysupra]

anybody? I have taken the water filter out to see if **** in the system but it was clean as a whistle, The water that drained out the system was dirty but not black. It ran clean looking but when put in a clear glass you could see it looked a blue/green colour. The water felt very greassy like to the touch. I guess this is the inhibitor?

 

[Agile]

Blue green water is sometimes the result of a cleanser which has not been drained and flushed out of the system!

The plate HE is blocked!

HE stands for heat exchanger!

Tony

 

[mattysupra]

maybe i should flush the system out myself then. So you are saying the HE is blocked? even tho there is loads of flow? If your sure, can i remove it and flush it with a hose pipe maybe? I think there are two on the boiler, one at the bottom (small) then the main one. Will both need flushing? How does the boiler know its blocked to keep turning on and off?

 

[Agile]

Its the plate HE ( the small one! ).

The boiler does not know that its blocked.

What the boiler does know though, is that the flow into it gets too hot so it turns off the gas until its cooled down.

Tony

 

[mehran]

the plate heat exchanger transfers heat from your primary fluid(the water that circulates around your rads and main heat exchanger to your domestic hot water(DHW)... so the fact you got 2bar water pressure out your hot tap means **** all.

your boiler don't give a flying **** that DHW plate HE is blocked or not, it is only making sure that the primary water does not boil...so it switches off if it gets too hot, it is getting too hot because most likely DHW plate HE is blocked.

 

[mattysupra]

thanks for getting to the ****ing point! So one last question, the HE i need to flush, which one do i remove or is it both? I take it i can just remove and give a good flush?

P.s do i need to remove them to clear them or another power flush?

 

[Agile]

Its the plate HE ( the small one! ).

Tony

Dont you bother to read what I write in answer to your questions?

Are we wasting our time giving you all this free advice?

Tony

 

[mattysupra]

Its the plate HE ( the small one! ).

Tony

Dont you bother to read what I write in answer to your questions?

Am I wasting my time giving you this free advice?

Tony

It looks that way dont it mate, sorry i never realised you had replied also. i scrolled down and went to the last post Thanks for your input.

One last question tho, can i remove the the stat and see if it will run without it to make sure this is the problem? I just guessed the water coming out the thing would be really hot before it cut out but you can keep your hand under it just about!

 

[htgeng]

Tony
One last question tho, can i remove the the stat and see if it will run without it to make sure this is the problem? I just guessed the water coming out the thing would be really hot before it cut out but you can keep your hand under it just about!

Do as the man says. If you take the approach of removing the stat you will most likely b*gger something else up.

 

[mattysupra]

o.k then, i will give it a go tomorrow. Will let you know the result!

 

[mattysupra]

All sorted, thanks for the advice. It was the hot water heat plate (HE). I flushed it out and also cleaned the divertor valve at the same time. I guess the original power fush never got rid of all the crap! Anyone recommend someone around birmingham to get it done again?