Alpha CB28

[fleabo]

Boiler: Alpha CB28
Age: 4 years

(I think) there is a seal on the Alpha CB28 just below the DHW flow valve assembly. (In my servicing instructions it is Fig. 23 nadd 27.) This seal appears to be passing water so I am contemplating removing the flow valve assembly and replacing the seal. The leak is intermittent.

My main concerns about attempting to replace the seal are making sure that I have all the relevant seals and spares to hand:

To remove the DHW flow valve assembly, I need to remove the DHW heat exchanger. Will I need to replace the seals and if so what is the relevant seal kit?

I also will have to remove the diverter valve assembly, which the DHW flow valve is part of. Will I need to replace the seals and what is the relevant seal kit?

The two fixing screws that hold the DHW flow valve in place on the seasonality valve appear corroded and I am fearful that in trying to remove them I will shear the heads - any tips and advice on the best way to approach the removal of these screws? What is the purpose of the two fixing screws below the flow valve assembly, and can I get replacement screws and seals (as I think it is seal that is passing)?

Any other advice most welcome - it has been a while since I have done any plumbing work.

Thanks

 

[fleabo]

Hi

I wonder if the seal kit 3.013391 will provide all the replacement seals I may need for the job? I can't find a list of what is actually in the kit.

Thanks

 

[nickso]

this may be of interest.

//www.diynot.com/forums/viewtopic.php?p=933415#933415

i dont know the seal kit number but if its for the diaphragm it includes all the diverter seals.

 

[fleabo]

Thanks Nickso,

Alpha Technical recommend 3.013389 kit which I understand to be a diapghram kit.

Does anyone know if I can make the repair of teh O-ring seal without removing the heat exchanger from the diverter assembly?

Cheers

 

[ChrisR]

Yes if you have the right sort of tools, but removing the hex only takes a couple of minutes. They wouldn't normally leak but this is where diy is a pain - yours will leak, and only pros will always have the right seal to replace it with!

 

[fleabo]

Thanks.

I guess I should have a seal kit (if there is such) for the heat exchanger too - just in case I need to remove the HEX as well?

 

[nickso]

if you are removing the diaphragm housing you have no choice but to remove the dhw heatex to do so.

your seal kit should have all those seals in it.

 

[fleabo]

OK, I got the seal kit and got around to attemping the repair tonight.

Two big problems I face:

I can't, for the life of me, budge one of the unions on the diverter housing. Any tips on possible methods of shifting it? I cannot remove the diverter and fix the O-ring without disconnecting this union.

Also, as was highlighted in a previous reply (thanks), the two small screws are corroded and will not shift. I have tried WD40, 3-in-1 etc, and tried bull-nose pliers but to no avail. Any other tips or work arounds?

Sorry, these are really basic problems that no doubt those experienced in plumbing could sort out quickly, but it has got me stumped...

 

[Agile]

Perhaps you will now be able to understand the problems that professsionals face every day.

You might also understand why those who quote fixed prices for some jobs have to include sufficient to cover difficult senarios.

You have chosen to try to replease just small sealing parts. Presumably to save your money.

Most professionals would replace the whole unit !!!

Tony

 

[fleabo]

Tony,

Thanks, I can fully understand the pressures that professionals are under day to day.

Do you have any tips on how to budge the union and remove the corroded screws, as a pro would have to do this anyway, whether they were replacing the whole unit or just the seal.

Cheers

 

[Agile]

Each situation has to be considered on its merits.

There are only two solutions, applying heat to expand part of the problem and an impact wrench for seized screws.

Those on your model are notorious for shearing off !

Replacing whole units gets round some of the worst problems and enables us to give a guarantee on the parts we replace.

Tony

 

[ChrisR]

impact wrench

Impact screwdriver I expect he means - a different tool.

 

[Paul Barker]

I can't work out from what you have said what you are doing or what you should be doing (which is worrying).

There is no big nut on that boiler that a competent boiler repair person cannot undo with one attempt. We however have to use all tenacity endurance cunning strength and capability almost every time. But we always achieve, there is no-one else.

How we achieve the big nut problems are most often by having the type of tool that fits good or grips tighter the more force we require, one for each part so one on the diverter valve, one on the nut, and with an eye out for sharp metal parts that might skin us when it gives, we grip and apply a mighty force in the correct direction for as long as it takes. It is possible, it always works. Those nuts are all accessible and undoable by the person with adequate tools strength and endurance.

The small screws I don't understand. There are two grubscrews, one holding a small brass part called simply a manifold, and the other holding the diverter valve in that part. Usually only one of these is to be undone. As a matter of course these are stuck. Typical workaday scenario for this diverter valve. Often have to take the other one out instead and work on the whole thing on the bench afterwards. Sometimes with a junior hacksaw blade you can cut a new slot in the grubscrew to undo it.

wd 40 in there is as much use as a onelegged man in an bottom kicking contest. The right tools the right approach and usually only one chance, is what you have with that grubscrew. (A good enough reason to use a professional first time round)

As for seals you don't get them all in one kit unless its the big seal kit,
forget the number.

The firbre washers are standard 1/2 in and 3/4 in (but not tap washers), the black and red o rings must be repalced every time with correct part.

Additionally, often the red o rings at the primary pipes where they enter the primary heat exchanger, at this time, ought to be replaced or in anycase after all your wrything, should be replaced as well. You get just enough red ones in the big seal kit. You will have no spare red o rings.

You have taken on a task an alpha service agent could do in 10 minutes and achieve it every time, a competent generic boiler repair person an hour and a trainee I would expect to fail.

Your chances are slim.

*************************
Mod the Punctuator, has been.
*************************

 

[nickso]

OK, I got the seal kit and got around to attemping the repair tonight.

Two big problems I face:

I can't, for the life of me, budge one of the unions on the diverter housing. Any tips on possible methods of shifting it? I cannot remove the diverter and fix the O-ring without disconnecting this union.

Also, as was highlighted in a previous reply (thanks), the two small screws are corroded and will not shift. I have tried WD40, 3-in-1 etc, and tried bull-nose pliers but to no avail. Any other tips or work arounds?

Sorry, these are really basic problems that no doubt those experienced in plumbing could sort out quickly, but it has got me stumped...

some of the nuts can be tight. if you use a good adjustable spanner that wont slip off or damage the nut and grip the body of the diverter with a pair of good pump pliers to counteract the pressure of the spanner most will come off easy enough. the only exception is the nut that is facing you.

the small screws do sometimes come off with wd40 but if they are badly corroded they sometimes dont. both screws need to come out as the seals on both parts will undoubtedly leak. leaving them to soak in wd40 overnight could help. ive removed them with pump pliers before if the heads are knackered. if they wont come out drill the bottom one out to get the unit out or order up the entire manifold body. i'd drill it myself.

when you put the new screws in put some non setting silicone on them to protect them from the enevitable water leaks that will appear over the coming months. doing this and immediately fixing any leaks on these leaking sieves at least gives you a chance of getting the diaphragm out in "10 minutes" next time and becoming a service agent hero like paul barker.

 

[Agile]

impact wrench

Impact screwdriver I expect he means - a different tool.

See:-


http://en.wikipedia.org/wiki/Impact_wrench

Tony