NOT BOATY - but mechanical question on my home boiler

ShipsWoofy

ShipsWoofy

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I have a Worcester 240 boiler.

It has two or three problems, or symptoms I dunno.

One is a worn Giannoni Diaphragm in the Diverter Valve. Fine, I have found one on Ebay for a fiver, no biggy to change (apparently plumbers can charge over £100 to replace this, even I can do it in under 20 mins). I am getting central heating and hot water but...

The trouble is, there is a tell-tale behind the housing on the diverter which is dripping away. I can see no way to stop this as I have not yet removed the whole diverter assy. All I can see is an allen screw behind the tell-tale on the body, does this allow access to a seal if I have the unit out?

I had another leak on the self sealing pipe into the diaphragm housing which I have just replaced the 'o' ring. This did not leak prior to me disturbing it tonight, thank god for a shed full of rubber seals and fibre-washers.

Could a leaking Giannoni Diaphragm be the cause of the dripping tell-tale or should I suck it up and buy a whole new diverter valve for £55 ?? <span style="color:red"> correction, £25 from bes.co.uk </span>

Fault 2; When I hit the central heating switch and the unit fires up, the pressure rises by almost 1 bar, it used to rise by about 0.3 max. Is this a separate fault or could it be a symptom of the perforated diaphragm? I don't see how as it is my understanding, the Giannoni Diaphragm turns the boiler on when a hot water tap is turned on, should I be looking for something else?

The boiler is getting on, but I do not want to change it when I can fix it for a few quids, oh and I'm mean, hence I use PBO! /forums/images/graemlins/grin.gif What I don't want to do is change the Giannoni Diaphragm and still have a leak, as this is near 14 years old, I don't really need an emergency spare.

I will stop there and thank anyone for reading thus far, and thanks in advance for any help I am sure I will get, PBO never lets me down..

J

<span style="color:blue"> EDIT>> Just read another forum with lots of info and I am getting a bit of a grip of what has been happening. First and I forgot about this, when hot water is running, rads start to get warm, this is it appears a diverter valve classic. Along with the dripping tell-tale I have just ordered a replacement unit, which comes with the diaphragm.

2. The pressure rising appears to be the expansion tank, but I have read mixed messages concerning this. On the front of the tank is car tyre type valve, one guy who described the fault I am getting said he bled this and all is now well. Another chap said, oh no, you have to put a foot pump on that and pump up to 5lb pressure. hmm, I will read the manual tomorrow as they are two completely opposite pieces of advice, any thoughts here? </span>
 
I'm not familiar with this particular boiler, but I wouldn't muck about fiddling with the diverter valve, just replace it.

The pressure problem is caused by a fault in the pressure vessel. It has either lost it's initial charge. Or, the membrane has perforated.

Look round the pressure vessel, there will be a Schreader valve somwhere. Knock off the water and recharge the air side with a bicycle/foot pump. The initial pressure is usually 1bar. The manual will confirm.

If this doesn't cure the problem, you'll need to replace the pressure vessel.

All these problems are eminently fixable.
 
Got one at work .. Been running for years apart from .. Pressure Valve for Hot Water .. Same as Yours .. Twice .. Also the fan at the top .. Fan Flue .. Strange problems like not starting was the fan running slow .. So two new fans .. Oh and a new control board .. a new battery on the timer unit .. Apart from that its been great .. Oh ours leaks from underneath to so we just have a tray to catch the drips .. /forums/images/graemlins/smile.gif
 
Most of these type of water sections have a diapragm moving a spindle up and down that operates micro switches. The spindle passes through a seal and often it it this that leaks. If you can get a complete assembly for £25 I would do that.

As already said the pressure increase must be down to the reduced space in the expansion vessel due to either the diapragm leaking water into the air section or air leaking out of the shraeder valve. carefully press the shraeder valve and see if you get water out. if not de-pressurise your heating system first and then using a car pump, pump the pressure vessel up to around 0.8 bar before re pressuring the central heating. But I would not spend to much on a boiler of this age though.
Pete
 
A few years ago (when I first started enjoying this forum) you would have been absolutely savaged for this post by a few people who seemed to dominate.
I remember posting a sympathetic reply to one poor chap (who had been torn to shreds) telling him that he had been 'scuttlebutted', but that didn't seem to go down too well either.
Anyway, things are better now, and good luck with your boiler.

Regards.
 
re the pressure rise - remove the pipe supplying the expansion vessel and check the it's not blocked - run it through under a tap to flush. Pressurise to around 5 bar when reassembled.
 
[ QUOTE ]
re the pressure rise - remove the pipe supplying the expansion vessel and check the it's not blocked - run it through under a tap to flush. Pressurise to around 5 bar when reassembled.

[/ QUOTE ]

Only charge up to this pressure if your property is around 50metres high /forums/images/graemlins/grin.gif

but as stated it's worth checking the supply pipe as they can block up.
pete
 
I have a Worcester boiler and although I can't answer the diverter valve one, I've recently changed the expansion vessel - same symptoms as you. I was getting water out of my schrader valve so I knew the diaphragm was knackered. As has been said, a very easy fix. I took the opportunity to drain and flush the system and put some new inhibitor in while I was at it. I also agree that 5 bar is WAAAAAAAY too much pressure. 1 Bar equates to about a 10m head - which should be plenty for an ordinary 2 storey house.
 
Ditch it!

I'm sure the other replies are right, but I had a 280 and once the problems started, there was no end to them. Changed diverter valve, expansion vessel, PRV, both thermistors (at different times) and eventually the modulating gas valve. Repaired one fault with the control PCB, and lived without the battery back-up for the timer. All between 5 and 10 years old.

I was bitterly disappointed, as I had helped a mate install two Worcester combies previously (24/70 ??) and these both lasted very well (still going 20 years on, as far as I know).

Andy
 
Thank you all for the advice thus.

I expect the diverter to arrive this morning and we will fit it this evening at which point I will also check for any blockage in the leading pipes and gauzes that I have seen on some pipe-ends.

I did notice a thick black sludge on the diaphragm I removed to check last night, this washed away to show perforation on the rubber, but the diaphragm was and is doing it's job in that the boiler turns on.

I can't afford (well, don't want to afford) to change the boiler, but I do want to fix it and then take out an insurance policy with gitish gas or similar, that way if the boiler dies in the future they will change it. I intend to let the property so have no urge to spend a fortune on a boiler I wont enjoy.

I have seen a easy fix that involves fitting a T into the closed system and adding a generic expansion vessel which are about a third of the price of a boiler one, but this is a bit messy I think. I am hoping that it has just lost pressure, the system has been drained down a number of times and I confess to never actually bleeding though the boiler properly only the rads, we'll see. I have never ever seen water coming from the overflow/pressure valve which is the first symptom apparently that there is an expansion vessel problem, again, we'll see.

To those that advocate bunging out the boiler, how very PBO /forums/images/graemlins/grin.gif Shirley a jamming diverter is not a good reason to spend upward of £800 for a band new boiler, I must live in a different world to most on here it seems; no wonder technicians like myself struggle to make a living when throw away seems easier than a quick fix, I am saddened by this, especially on here /forums/images/graemlins/blush.gif
 
Can't argue with the way it's going on pbo, but you didn't mention the black sludge before, unless I missed it ?
Had this before and found it's a reaction between steel and copper that causes it, also creates a build up of hydrogen in the water which often surfaces at one particular radiator (try using a bleeding key on each and see if there's one that releases a lot of gas, but don't light it) and the only solution I found was a product from Fernox (sp) which you put into the header tank to deal with it.
Think they suggest a flushing solution first, then another to protect your system. Much cheaper than a new system, and far more pbo
 
It was more of a, how to describe it, a coating that I could rub away with my fingers, not unlike a wet version of the black rubber you get off an old fan belt. The brass behind and pipe-work is polished; I had to replace an O ring on the bizarre telescopic pipe that goes to the heat exchanger and that too was clean as a whistle. Not that I am saying I should not worry here, but other than the coating on the diaphragm I have seen no other signs, fingers crossed.

I had the bathroom rad off (which is the non-thermostat rad) and draining the system twice (don't ask!) showed clear albeit a little yellow water. I must admit that I did not replace the inhibitor that time and will wait until I am happy the system has stopped losing water and is working properly.

I have read a few expert testimonials concerning draining the exchanger to clear any slurry and might do that par the course as I will have to drain the system once again tonight or at least when the diverter arrives.

Should I be very worried if the system is not crystal clear, is any residue a point of concern?
 
Not a heating engineer so can only comment from experience.
Residue isn't too much of a problem as long as the system has been treated, but if you want to try an even cheaper solution (or indeed, find out if this is the problem) there is a valve on the market that releases the gas from the system.
I don't suggest the following to anyone because it's pretty radical, stuff that can go bang shouldn't be helped to do it, and all that yadayadacrap
But, find the radiator that's got the gas in it, and release it gently, then light it up. Naked flame to the valve output and if it lights up, you have a problem caused by different metals and an electro mechanical reaction causing a build up of hydrogen and sludge (most likely iron oxide)
Worked for me, let me know if it does the job
P.S. If it lights up, close the bleedin valve, don't try to blow it out, the gas pressure will keep the flame outside the system.
Kids, don't try this at home
Dan, it's pbo, which means practical, not eggspurt opinion only
 
what you have there is black iron oxide sludge and its well worth trying to get rid of it while its still in a liquid state. If it gets to bad it will settle and harden in the radiators and clog them up.

b&q sell a system cleaner that will do the job.
 
I hope the poster who suggested you pump it up to 5 bar was making a typographical error, Thats roughly 65 to 70 lbs/sq inch....don't go there for heavens sake.

Get a car tyre pressure gauge on the schrader valve on the expansion vessel. as long as its about between about 0.7 and 1 bar you are OK. Yes, its possible the tube to the pressure vessel is blocked and this is worth checking.

Those are the commonest causes of sudden pressure jump..after which it squirts it out of the Pressure Relief Valve and you lose water/pressure from the system.

"£100 to change the diverter"......no..I'd charge you a lot more than that!!!! I've got two children and yacht to provide for for heavens sake. /forums/images/graemlins/laugh.gif

Tim
 
[ QUOTE ]
To those that advocate bunging out the boiler, how very PBO /forums/images/graemlins/grin.gif Shirley a jamming diverter is not a good reason to spend upward of £800 for a band new boiler, I must live in a different world to most on here it seems; no wonder technicians like myself struggle to make a living when throw away seems easier than a quick fix, I am saddened by this, especially on here /forums/images/graemlins/blush.gif

[/ QUOTE ]

I've done my PBO bit on these (Practical Boiler Owner), as per the list I gave above. However there comes a point where one realises that the equine beast that one is flogging into action has, in fact, departed this world.

Just trying to save someone else from the same fruitless expentiture of effort and money /forums/images/graemlins/smile.gif

If you're intending to rent the place out, then I would **definitely** replace the boiler... Tenants have an annoying habit of making even the most reliable things break down.

Good luck, regardless!

/forums/images/graemlins/smile.gif

Andy
 
[ QUOTE ]
A very short answer

Change the diverter valve and the expansion vessel............

Tom

[/ QUOTE ]Yup, both now changed and boiler running up and firing. Pressure sat fairly constant finally and the boiler has stopped making the racket it had been for the past well, I had left it a long time. I have learnt how boilers work, how a closed system works etc. All in all, a lot of pain but at least I have worked it through.

Thanks all for the help and advice, I do genuinely appreciate the time everyone took to help me, especially on a non boating type subject, though I think the basics can easily cross from one to the other so it was not seriously out of place here, maybe.
 
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