baxi 105e instant.

[billynm]

good evening all.

just signed on to to the forum tonight.Can any body help me with the above boiler.Central heating flow is hot all around the house but not all the rads are hot,upstairs are downstairs no.The pump is running,neons quickly run up to the max,burner goes out after the temp drops boiler fires up runs till neons hit the max and out it goes again.all this happens very quickly as though there is no circulation.

system has been bled free of air, any thoughts please.

Pump ,pcb, ch,and hw diaghrams have been changed.

 

[Agile]

Who changed all those parts?

Why did they change them?

Who is in charge of solving the problem?

Tony

 

[billynm]

thanks for the quick response.

i changed them as the diaghrams .

Diaghrams perished.

Pcb was a suggestion of a. n other.

and i am in charge of repairs.

 

[Agile]

And where does the new pump fit in with that?

I do have to say that the cost of all those parts would probably be more than calling a competent boiler engineer to correctly diagnose the fault.

Have you cleaned the return gauze filter? Thats free and takes a few minutes! ( Tip, they are sometimes fitted on the flow instead! ). Not necessarily the problem but a free good place to start!

Tony

 

[billynm]

hi tony.

thanks again for the reply.

pump was a cheap purchase brand new so for £30.00 why not ?

yep cleaned the gause nothing in it actually.


So no other suggestions ?

the boiler has been in 3 yrs, so maybe i will replace it with a real old fashioned system , cylinder etc etc.

.
keith

 

[diverdee]

is the plate exchanger getting very hot while it is doing this ?

 

[billynm]

hi diverdee.

thanks for the reply.

the plate exchanger is quite hot when the problem arises. hope we are on our way to solve this pain in the ..... .

kind regards keith

 

[Agile]

Did this radiator balancing problem suddenly appear overnight?

Are the d/s rads fed from decenders from upstairs?

Tony

 

[ChrisR]

very quickly

How quickly?

Before the upstairs rads are hot?

 

[billynm]

ok here we go

the rad problem has appeared over a 2 wk period approx and got steadily worse.
downstairs rads are fed on decenders .upstairs rads get hot after approx 15 or 20 mins.

i have also noted that the flows downstairs are hot yet the returns are cold,indicating that the return is not happening.

i have drained the system then closed off the flow and return to every rad,filled the system back up then opened every rad 1 by 1 and bled the system of air, still no good.

keith

 

[Agile]

Thats the usual situation of sludge getting into the d/s rads but not getting carried up because its too heavy.

Most DIYers end up taking the d/s rads and flushing them through in the garden with mains water and taking a lot of water out of each pipe into a bucket.

If it were in cood condition you could clean it with citric acid but that would risk holing the rads.

If its an open vented system this will probably have resulted from pumping over.

Tony

 

[diverdee]

are u sure its not just diverter valve passing and return just up to temp too soon

 

[Agile]

If the system is clean and properly balanced then if the diverter valve is sticking all the rads would react the same.

If the system was not properly balanced to begin with, it could well be the diverter sticking.

Thats much harder for a DIYer ( and some professionals ) to identify.

Tony

 

[billynm]

I have taken off all downstairs rads just to be sure,and only a minimal amount of black dirt in everyone of them.Flushed as suggested and replaced.

Still the same issue, the system has been run on descaler/cleaner,inhibitor etc, so not enough crap in the rads to stop the return from working.

sorry fellas, i am ready to throw this boiler out of the window.

any one suggest a good combi at a good price?

keith

 

[Agile]

There are plenty of good boilers aroung but yours is still quite repairable.

It now seems that the system needs balancing but the prime culprit is the diverter valve. The rear part is not following the diaphragm unit.

A replacement diverter is probably around £100 or if you love a bit of fun you could take it all apart and scrape all the dirt off and perhaps boil it in citric acid and then dry it and assemble with silicone grease on all the sealing parts.

I do have to say that commercially I only replace them and have found that even cleaning them is not always fully successful on the odd occasions when I have tried it.

I have sometimes managed to free them using citric acid just in an in situ boiler but unless you are very conversant with the techniques to be used thats unlikely to work.

Tony