Black residue in the steam wand

Lacehim

Hi Everyone.

I've had this leaky wand for a while, and I pulled the tap off to take a look, and turned the seal around to see if that helps it seal.  Didn't work.  The wand has started to get really hot when the machine is left on. It's a cool touch wand so this isn't normal.

Jack said it might be some milk that's been sucked up inside, so I pulled it all apart.  I put a cotton bud own inside the fitting that is attached the machine (with the tap off), and there is some black residue there, and it was also evident in the plastic tub inside the wand.  Is this caused by milk or something else?  The steam has been quiet watery since I got the machine, and I purge the wand post steaming the milk.  Now and again I haven't done it instantly when distracted by kids and stuff.

The water in the boiler is clean... I'm just not sure what's causing the issue here.  The seal is very basic, just a bit of rubber that pushed against the inlet to stop the flow.  I find it hard to believe that milk would get up inside the valve when it's closed, so how would this gunk get in there?

HELP!

Koffee_Kosmo

If everything is clean before the wand ( and it should be in a less than six month old machine ) It may be the rubber seal slowly decomposing and depositing in the steam wand cavity Rubber and compounds can do this under heat shock Try a silicone material that is high heat tolerant and it will probably fix it The only other thing that will make water black is minerals going stagnant KK

Lacehim

Well it's not KK The rubber seal looks fine, and is red.  The wand had black residue at the bottom and top, I ran a pipe cleaner (it was black, so not very useful) through it.  The ball joint also has some of the same gunk, and inside where the tap screws into.  I also put a cotton bud into the hole pictured that is normally sealed by the tap, and it too has the same black gunk in it.  That leads to the boiler so I'm a bit worried this crap is everywhere in there. I've never had milk contamination before, so I don't know if this is it or not. The HW tap is unaffected BUT wasn't perfectly clean, just a tinge of something on a cotton bud. Take a look at the photos, the cotton buds are very black at the tips!

Koffee_Kosmo

Do you have a friend ( scientist / chemist ) that can analyse the gunk That way there is no second guessing Just thinking out loud - It's possible that some lubricant can do this as well KK

Lacehim

Could be.  Chris at TC mentioned there was excessive lube in the group when he replaced the spring on his evaluation machine. If it is a milk contamination what can I do about it?

Koffee_Kosmo

on 1368439792:

Could be.  Chris at TC mentioned there was excessive lube in the group when he replaced the spring on his evaluation machine. If it is a milk contamination what can I do about it?

It's not milk contamination Milk emulsifies with passing steam but may leave white calcium behind Milk can also taint the boiler water if I syphons all the way there - and it will have a  stinky smell Regarding lube - If its coloured black or dark ? The steam will emulsify the oils and leave behind the colour to cling to the steam wand sides KK

Lacehim

I pulled it apart again!  Still won't seal 100%, and if I tighten it fully it leaks, but if I back off it stops with a tiny leak.  On the end of the tap there is a spring loaded part that holds the red seal. Still not sure where that black guff came from.

Koffee_Kosmo

on 1368495060:

I pulled it apart again!  Still won't seal 100%, and if I tighten it fully it leaks, but if I back off it stops with a tiny leak.  On the end of the tap there is a spring loaded part that holds the red seal. Still not sure where that black guff came from.

Is there an "O" Ring in the shaft ? Can you get a scematic to see the breakdown of the components KK

Lacehim

No O ring KK.  Just that red disc at the top. I've contacted Jack, hopefully he can prod QM to figure it out.

Koffee_Kosmo

Have you pulled the two sections apart ? The spindle brass section from the knob If there is an "O" Ring it will be there KK

Lacehim

No.  I doubt there will be any oring KK.  The design is totally different, and if I pull that spring loaded bit apart I might not be able to put it back together again.  I can't even see how it goes together to be honest. The design is a bit like a pipe with water coming out, and you put your finger over the hole to stop it. Jacks on the case, but it's unusable as it is really.  It can't be left on and no one seems to know what the black stuff is.

Koffee_Kosmo

Regarding Leak --  it's one or a combination of these three things 1) The red seal is worn 2) The thread has run out so it does not press the red seal hard onto the other surface (seat) 3) The other surface (seat) is not true and is allowing steam to push through KK

derrilex

So its just a rotary knob Lacehim and the red seal seats in the base steam tap ? I'd say the seal is shagged or the seat is not parallel to the seal, or both. Any strange marks or ridges on the seat ?

Lacehim

It's pretty tight in there.  There is a small mark (you can see it in the photo on the left at 8oclock, that's it. The seal looks ok, but I turned it around and that make it worse, so I put it back, and it's worse again. Got some new seals on the way I hope, maybe that might fix it.

Gra

I would recon this is food grade grease that courses the black goo this can also make the milk look like it is turning as well,the milk thickens and hase a lot of small bubbles . The notch on the seal is standard it is the same on the Alex it's best not to get any grease forward of the o'Rings so as the steam line and ball joint are free from any grease... Cheers Gra..

Lacehim

Thanks Gra.  It certainly doesn't smell. I think I've found what the issue is with the wand.  I think it's the tap (the handle part that is).  I've attached a few photos. I took the HW tap off, and compared the too.  When you unscrew the tap the part with the stopper moves out.  With both fully extended you can see the difference.  The HW tape extends a lot longer out.  With the steam tap it seem that it screws out at the same rate, but on the final part of the turn it stops, were as the HW tap kept going until fully extended.  I then took the chrome vapore cap off, and it came off quite easily, and inside there was a lot of fine brass shavings.  I also noticed the the plastic around the brass has cracked and I think this is the issue. I tested the tap, and sure enough as it turns the stopper extends, but on the final part where it stops the plastic turns on the brass and the brass part starts to pop out!!!  I took the whole mechanism apart and it's all in working order so by my observations I am certain the the plastic handle part is the cause.  You can't seem to remove this from the brass part either.  I can't get the chrome HW tap off. Hopefully Jack has a spare tap for me.  Still not sure what the black stuff is and I'm waiting for a response from QM.

C-man

sounds weird and must be frustrating, sorry for your loss. what are you doing, drinking long blacks? My steam wand is leaking now and I am too busy to even look at it.

derrilex

That's a bugger Lacehim. Not that you should have to, but have you given any thought to retro fitting the flick type taps ?

Lacehim

It's not all doom and gloom.  Now that I figured out the problem I flicked the HW tap over with the steam so at least I can still make coffees.  Jack had some spares so they are in the post.  When I get time I'm going to have to pull it down to clean the rest of the black stuff off.  Not sure what it is but I don't think it's supposed to be there.  My main concern is what is it, and where did it come from! Jacks been great the whole time, he's always positive, and happy to help get things fixed.  You can't ask for more really.  It's nice to know that he's getting support direct from QM too.  Hopefully they will have an answer to the black stuff. The flick type taps are an option.  Jacks looking into the cost for me.  I like the idea of them, but the knobs aren't hard to live with.  They only require a little turn to get full steam.

C-man

the mystery of the black goo, what things are there that color inside? Lube Rubber nylon plastic that's about all I can think of. Maybe it will not seal because some seal has melted?