Water level probe removal - help needed

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AdrianN
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#1: Post by AdrianN »

To cut the story short, the probe on my machine (La San Marco 85 Flexa) was inserted all the way down (it has a bend near the top, was inserted as deep as this bend will allow). Apparently this was done by a fellow from the service (I bought the machine second-hand, previous owner was a small company using it for the employees) as a method to avoid any work. Basically he plunged the probe deeper and deeper as the tip became covered with calcium deposits.

Upon discovering this, I tried to remove the whole thing in order to give it a good cleaning and adjust it properly. However the base nut (the one that is screwed into the top of the boiler, using a copper spacer) appears practically impossible to remove without taking the boiler out of the machine. I tried as hard as it seemed reasonable but had to stop eventually fearing I could crack the boiler against its mounting bracket. Obviously I cannot use an impact wrench with the probe in place.

The next approach was to remove the probe itself by unscrewing a bit the upper nut and then pulling the probe out. It wouldn't work, either it has a bend inside the boiler as well or the deposits are too big to allow it to pass trough the teflon sheath. While doing this I noticed that the teflon sheath wasn't completely rigid, so I figured out I could remove the upper nut completely without breaking it. However, after removing the nut the teflon sheath wouldn't come out either. I can spin it inside the bottom nut, but cannot take it out.

Knowing already that the bottom nut was practically impossible to remove, I put together the whole thing, this time with the probe lifted up about an inch. (an inch between the top bend and the top of the teflon sheath). It turned out that I didn't broke up the teflon sheath (thanks God) but now I have wet steam, of course. (on the other hand the noises made upon heat-up are diminished). So I'm going to re-adjust the probe level a bit, but the problem obviously remains.

Now, my question is: how can I safely remove the teflon sheath without breaking it, so I can clean the probe? Is there a method to do this, or should I stop pushing my luck and just make sure to use soft water, until it's time for a complete overhaul (as in removing the boiler)?

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erics
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#2: Post by erics »

The pic below is NOT your assembly but that from another machine.



The Teflon sleeve is not threaded (when new) but male threads are formed on the middle "hub" when the nut (item 2) is tightened. You may be able to gently unscrew the Teflon sleeve turning it counter-clockwise.

If not, replacement probes and Teflon sleeves are readily available for around $20.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

AdrianN (original poster)
Posts: 51
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#3: Post by AdrianN (original poster) »

Hi Eric and thanks for the reply. My problem is not the cost of the probe but the difficulty (read impossibility) of removing the base nut without taking the boiler out of the machine.
I tried to gently unscrew the teflon sheath but no luck. I think the middle"hub" (as you called it) is stuck under the inner thread of the base nut. Perhaps the upper nut was tightened too much and the hub expanded a bit.

Since the teflon is still soft (as opposed to cooked and frail) would it be safe to use a bit more force?

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erics
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#4: Post by erics »

Sure, because even if you mess up the Teflon, it can be easily replaced.

If the probe and sleeve come out, clean the probe with silicone carbide paper or a wire wheel.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

AdrianN (original poster)
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#5: Post by AdrianN (original poster) »

The problem is that I can easily purchase a probe that is suitable for my machine, but there's no guarantee whatsoever that every part of the new probe will be fully compatible with the probe on my machine. So if I break the current teflon sheath, the new one may require me to remove the base nut in order to install it.

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erics
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#6: Post by erics »

Your "base nut" is the equivalent to item 4 in my pic. There is no need to remove it if you can get the Teflon sleeve and old probe out as previously advised.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

AdrianN (original poster)
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#7: Post by AdrianN (original poster) »

Yes, exactly, that's the part I called "base nut". What I fear is that if I break the teflon sheath, the new probe's sheath and top nut (items 2 and 3 in your pic) may not be compatible with my old base nut (item 4) . Therefore forcing me to remove the base nut, with all the trouble it may involve.

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erics
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#8: Post by erics »

Well, that's your choice but, to the best of my knowledge, all of these Teflon sheaths are identical.

The base nut has 1/8"-28 BSPP female threading and the gland nut has (obviously) 1/8" -28 BSPP male threading.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

AdrianN (original poster)
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#9: Post by AdrianN (original poster) »

Yup, that's the info I was looking for, in order to stay on the safe side. So basically pretty much any teflon sheath from a level probe should fit?

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erics
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#10: Post by erics »

Yes.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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