How simple is it to replace diaphragm in Worcester 24cdi?

[Spanky2k]

Hi all,

Long time visitor and reader here. I'm hoping some of you more experienced folk might be able to help me out. I'm pretty sure the diaphragm in my Worcester 24cdi boiler has gone. Can anyone tell me how simple it is to replace it in-situ? I've replaced a diaphragm on a different boiler before so I'm not a complete idiot but I haven't done any work on this boiler before. I have good access beneath the boiler but not the sides (it's in a cupboard).

I think my diagnosis is correct but just in case, I'll describe what has happened. Thames Water finally got round to fixing a leak on the street that I've been repeatedly reporting for nine months. It turns out it was from the lead pipe from my house to the feeder pipe in the street. They had to turn my water off and on a few times during the repair process and I believe they've replaced part of the pipe.

Since the work done, hot water has gone on and off from some taps and hasn't worked from others unless I open multiple hot taps. Central heating still works fine and if I leave it on, hot water from all taps works just fine as I'd expect (as the boiler is already on). I'm guessing this means that the diaphgram isn't working and the turning on and off of the cold water feed or a potential slight change in the feed's water pressure might have caused it to fail. It's an old boiler after all.

Any thoughts?

 

[Gasguru]

Yes it sounds a correct diagnosis...the shock of turning the water on/off with trapped air has finally killed the diaphragm.

It's one of the worst boiler repairs that can be done. Apart from the aggro of the diverter there's a chance the flow and return valves will leak in the process. You only have to look at them. It's turns a PITA job into a real PITA job. The auto air vent nearly always needs swapping too. Unless you're very patient it's not a diy job. Many pros avoid them too.

For the cost you might want to consider Worcester on a fixed price...they often swap out the entire bottom end and then it represents excellent value.

 

[ollski]

I don't really mind them. Don't touch any of the isolation valves or even brush against them. Stick a bucket under the white drain plugs, you will probably need to remove them and poke a very thin screwdriver through the blocked hole. Open the filling loop and remove the key as you loosen the plate to direct water into your bucket. Tape up your control box out of the way to prevent it getting soaked. I use a draper right angled screwdriver to access all the screws to the diaphragm housing but its still a fiddle. Good luck.

 

[45yearsagasman]

http://www.newtonnet.co.uk/house/boiler/

This might help.

 

[Agile]

I totally agree with Geoff above.

Normally I replace a whole diverter valve on the few occasions that I agree to repair this model.

It may be an opportunity to consider a new boiler. But if you really want to keep it then a Worcester fixed price repair at about £300 would probably be the best solution.

As an indication of the scale of the problem I once got a trainee to repair one of them under my direct guidance and that took 2 1/4 hours. It was for a friend but primarily to show the trainee that it was really a job which was possible but one better avoided.

Tony

 

[nickso]

Don't be scared off.

Buy a 20 quid diaphragm kit and get stuck in. Your first time will take about 2 hours but if you are any good you will manage it in an hour the next time.

Just take your time and don't be too rough with it, that's when the CDi fragility will bite your arse hard.

 

[johnplumb]

allow 3 hours.

Its a job that many professionals don't like doing as they can be iffy.

 

[Spanky2k]

This looks like something I can do with a bit of time. Not exactly a fun job but doable and I have the time on my hands so can save a few hundred pounds. At some point in the next couple of years we plan on putting a small conservatory on the back of the house which would require moving the boiler so I'd rather not spend £300 for a repair now when we'll likely just replace it with a new model then.

Can anyone tell me what kit it is I need to buy and where to get it? A diaphragm kit or a whole diverter valve kit?

 

[muggles]

87161567460 for the complete diverter assy or
87161405530 for just the diaphragm

Personally I'd do the entire diverter. The last thing you want to do is find that just changing the diaphragm hasn't worked and you've got to fart around getting the whole lot out again. you'll have lost the will to live after the first attempt. The whole thing is only about £70 anyway

 

[Agile]

Dopnt do it over the weekend.

Its easy to snap off some of the plastic parts at the front so you need spares suppliers available.

Also if a DIY repair gets too difficult then a professional is easier ( and cheaper ) to get to help during the week.

Tony

 

[ollski]

Reckon I've done 100+ and unless they are at the highest point they are generally a 2 hour job. Unless there is signs of a leak from the small holes behind the diaphragm housing I wouldn't change it as the internal o rings in the jig can be awkward. Just change every o ring when you reassemble. Or pay BG 180 odd quid and get a 12 month guarantee.

 

[Agile]

I did one once which was mounted in the kitchen with the base at about 1.6m agl.

Being able to have complete and comfortable access from underneath made it a far easier job.

The one my trainee had to do was mounted at 90° and over a steel sink ! Not so easy.

Tony

 

[gas112]

Your asking for trouble if you do this job yourself get someone in loads of pro`s side step them not a job for a diyer

 

[Spanky2k]

I'm going to give it a try. I was planning on replacing the whole diverter assembly but then I found a diaphragm kit for a little over a tenner so figured I'd just give that a try first. I ordered a pack of assorted O-rings to replace any I find in the process.

I'll be doing it on a weekday as I work from home anyway and the wife will be out one night for work leaving me a two day window to get it fixed in before I get aggro for not having any hot water! If I find I need any parts, there's a Wickes five minute walk from home and there's a Plumb Centre about 10 minutes away by car too.

 

[muggles]

Good luck!!