wirsbo a2450028 valve rebuild

429jim

I am trying to rebuild a wirsbo a2450028 manifold valve and can not figure out how to remove the stem from the body. Any help would be appreciated.

Dave Carpentier

Have you already seen this post, apparently showing the internals ?
https://forum.heatinghelp.com/discussion/comment/1680564#Comment_1680564

Alan (California Radiant) Forbes

I had the same problem and ended up replacing the manifold just like everyone else. The valve had leaked so long that the corrosion prevented it from being removed from the brass block.

The EP (engineered plastic) manifolds are a bit longer and I had to cut the PEX back to make it work.

429jim

thanks for the quick response you guys. I did see that post which gave me the inspiration to take it apart. So far so good, valve is out but just can't figure out how to get the stem out.

Dave Carpentier

My 20yr old ones are functional but starting to dribble out a tiny bit (no rags tied to them yet though lol).
I was hoping on doing the rebuild of the o-rings as well, but I have my reservations.
It seems like most people look at it, then end up swapping in a new manifold.

hot_rod

Remove the packing gland with a metric box or socket and you should find a snap ring under it. Don't lose it!
Find a spring, washer and o-ring next.

You may be able to find a new o-ring, but id the stem is worn or rough, it may not seal for long. Some are plated brass, some are stainless.

This is a Caleffi, yours should be similar.

429jim

Thanks Dave, I will replace the manifold only after I have made every effort to repair the valve.
Thanks to you Hot Rod for the great details. I don't see any clip on my valve stem, besides it is not very accessible down inside the body.

mattmia2

Does that washer slide down the shaft if you push on it to reveal a snap ring that holds it on the shaft?

mattmia2

Yours uses a spanner. I would file a thick washer with a flat edge and a notch to turn that nut.

429jim

Thanks mattmia2, the washer does not slide down the shaft. I don't see a nut on the shaft to turn?

429jim

I am also going to try an experiment using a rubber washer that fits snugly inside the black plastic cap to
help seal the shaft.

hot_rod

Well someone, somehow put that stem assembly into the brass body? Sometimes you end up destroying one toi learn how it was assembled. But I doubt you have a spare to practice on?

Here is how this Watts brand assembles. Pull the rubber seal washer off the bottom, it acts as the snap ring that holds it all together. The stem o-ring is still in the brass body, easily removed with an o-ring pick.

429jim

You're right hot rod, about all of it. I will try to pull that seal off later when I get a chance, that makes perfect sense. Thank you.

429jim

Update: seal is off, stem is disassembled. Found some corrosion on bottom of stem (I will polish the best I can), top looks ok. Found an o-ring in the black plastic cap so no need for my experiment. Now ordering new o-rings with a little bit snugger ones for the polished spots.

hot_rod

I'd replace all 4 rings, included is the one where it assembles into the trunk, on the brass machined piece. Plumbers stem lube when you reassemble.

mattmia2

I'd look for epdm o-rings in those sizes from a web site that specializes in o-rings. The OEM materials in most applications tend to be the materials that harden over time and stop sealing properly but are commonly available.

429jim

I will be replacing all o-rings from McMaster-Carr which you can get any o-ring you could imagine. Plumbers lube for sure.

hot_rod

If you can, peroxide cured EPDM. Crossed-links EPDM is much better for resistance to chemicals used in potable water. Same process used in pex A. Caleffi used peroxide cured EPDM for most seals, zone valve paddles, etc.

Viton is a $$ step up. If glycols, oils, or boiler chemicals are used Viton is a better product

Dave Carpentier

In theory, could you use some kind of JBWeld type of stuff to re-coat the shaft and eliminate the pitting ? Perhaps a thin coat and then spin it in a drill to sort of lathe-like file it back down ? Would need a nice micrometer to keep checking the diameter so as not to make it all too small.. just want round and smooth.

So, the main valve seal disc just pulls off of the pointy end with no c-clip ?

hot_rod

I mike it out at just under 3 mm. Can you work accurately at that size? It comes down to your patience level I suppose. You won't know if you won until it is all re-assembled and tested.

It is about a $15.00 part if you can find a replacement to fit. Supply House has the Caleffi for around 14 bucks.
Probably less than the postage on a handful of o-rings. If it needs new actuators and stems, time to upgrade to a Caleffi

But I also understand the pursuit is worth as much as the win for tinkers

mattmia2

If the o-rings are resilient again it will probably seal up just fine if you clean any crusty stuff off with scotchbrite. I found the o-ring only web sites had a lot more sizes and more size/material combinations than mcmaster-carr. You could also buy a dozen of a size instead of a package of 100.

429jim

hot rod: I ordered viton o-rings to improve my odds. Not sure yet how to handle the shaft imperfections and can't find a replacement shaft anywhere. My actuators are good for now. The pursuit is worth my efforts, for now.
Dave: Thanks for the ideas, I will be tinkering with it this weekend. No clip on the seal, I used a strait pick to try and shoehorn it while prying underneath with a flat screwdriver.
mattmia2: When I ordered viton o-rings the quantitys are much smaller, but still expensive. The scotchbrite and wire wheel helped a lot, but will try a couple more things this weekend.

mattmia2

Dave Carpentier said:

So, the main valve seal disc just pulls off of the pointy end with no c-clip ?

It is like virtually every inexpensive compression stop.

You could potentially replace it with a flat washer and a couple o-rings.

hot_rod

429jim said:

hot rod: I ordered viton o-rings to improve my odds. Not sure yet how to handle the shaft imperfections and can't find a replacement shaft anywhere. My actuators are good for now. The pursuit is worth my efforts, for now.
Dave: Thanks for the ideas, I will be tinkering with it this weekend. No clip on the seal, I used a strait pick to try and shoehorn it while prying underneath with a flat screwdriver.
mattmia2: When I ordered viton o-rings the quantitys are much smaller, but still expensive. The scotchbrite and wire wheel helped a lot, but will try a couple more things this weekend.

If it is hard water build up I would soak them in CLR, Sizzle etc.
Any scratches you leave on that polished shaft limit them O rings ability to seal. Even 600 grit would leave some small scratches. If the shafts are wore, your chances of a good long lasting seal go down.

I'm sure you have seen hydraulic cylinders on backhoes etc, there is a reason for that polished mirror surface on those rams.

Lube or spit on the washers. If they are hard, brittle, or break, you are in trouble. The tight fit over the stem is what keeps the whole enchilada together.

mattmia2

I was going to suggest rubbing compound. i have used that to clean the stainless disc on 2 handle delta cartridges. If you clean those with scotchbrite they won't seal properly anymore and you have to replace the cartridge.

hot_rod

mattmia2 said:

I was going to suggest rubbing compound. i have used that to clean the stainless disc on 2 handle delta cartridges. If you clean those with scotchbrite they won't seal properly anymore and you have to replace the cartridge.

Toothpaste even!

429jim

so I couldn't wait till this weekend, I took some of your ideas and ran with it. I did not use the scotchbrite. First I put some masking tape around the stem end I put in my cordless drill so I don't scratch it. Then I got some 800 grit automotive wet/dry sandpaper around the other end of the stem and started drilling. It turned out unbelievably smooth. Under magnification I can see fine scratches, so I will proceed with 1500 and higher as needed. Even though I am polishing brass on the bottom 3/8" of the stem I have lost very little on the diameter. The chrome finish must be very thin. All that has boosted my optimism. Thanks again all for your input.

mattmia2

Things can happen to the water chemistry that will make the chrome flake off without actual corrosion. could just be wear too.

Alan (California Radiant) Forbes

@429jim If you still need some replacement shafts, I retrieved this manifold from my scrap pile and I can send you the valves, but don't know what condition they are in.

RemyTCO

hot_rod said:

I mike it out at just under 3 mm. Can you work accurately at that size? It comes down to your patience level I suppose. You won't know if you won until it is all re-assembled and tested.

It is about a $15.00 part if you can find a replacement to fit. Supply House has the Caleffi for around 14 bucks.
Probably less than the postage on a handful of o-rings. If it needs new actuators and stems, time to upgrade to a Caleffi

But I also understand the pursuit is worth as much as the win for tinkers

Running into the same issue with the a2450028 valves - having couple that leaks. Did anyone figured the sizes of the two internal O-rings ? Much much appreciated !