I have a head-scratcher ...

I'm working on a 1974 Olympia Cremina. I have no long-term knowledge of this machine (an eBay purchase recently), so, I'm not really trusting anything that was set-up on the machine initially. It did heat up, etc., but, before beginning the teardown, a bit of steam was escaping from the safety valve. I assumed it was a seal failing, so, I proceeded with the teardown, etc.

I replaced all seals (with the OE rebuild kit). Things went fine (except for a broken sight glass, which was my stupidity ...).

I started the heat/pressure test, which is where the problem started. Despite replacing all the seals, a bit of steam was still escaping from the safety valve. I realized that it was actually being released from valve itself, not from the seal. Concern. I noticed that, even after the Pstat clicked off, the boiler continued to sound like it is very slightly still heating up (I know that this sounds crazy, but, it is almost as if it is still getting some small amount of power, like there is a very light boil going on inside, NOT the strong sound of the heater when it initially heats up until the Pstat clicks off). After releasing false pressure, within 10-15 minutes, the safety valve begins to release a small amount of steam, never stopping. So, this has led to bunch of attempts to fix things.

1) After seeing this overpressure I got concerned enough, and ordered a new safety valve (I had rebuilt/cleaned the original, but, this seemed like a small investment for safety purposes). I had read this:

Leak from Olympia Cremina Pressure Safety Valve

However, despite everything, the overheating seems to continue forcing the safety valve to release pressure.

So, I have done several more things:

2) I have tested all of the electrical connections and found no problems following the OE instructions here:

http://www.orphanespresso.com/Olympia-C ... 565-1.html

This included paying particular attention to the microswitch (it does "click" and the voltmeter reads off/on depending on whether or not I have physically compressed the Pstat) -- all seems correct. I was very mindful of this:

Replaced bad Olympia Cremina thermostat switch, now boiler won't turn off

and

Olympia Cremina too hot

3) I checked the power cord to ensure that nothing got wired incorrectly in case a new power cord had been installed at some point, like here:

Olympia Cremina 67 overheating

I mention all of this to show that I've tried to do my homework on this, but, it remains elusive ... It is still, consistently, when it gets up to full pressure, releasing a bit of steam from the safety valve, and I can still hear what sounds like a little bit of heating/boiling going on in the boiler after the Pstat turns off.

Can anyone help with this? Suggestions? Thanks!!!

Have you measured boiler pressure with a steam wand pressure gauge? I wonder also if the soft boil you are hearing after shutoff is residual. Does your Cremina need descaling? Although you've said you hear the microswitch shutting off, are you hearing something else so the pressurestat is still on? If so, is it clogged with scale or debris? Is it set too high? Are all the wire contacts firmly attached? Just some thoughts. I realize you have a lot of this covered.

Great question, one and all.

See my responses below.
1) I measured the boiler pressure with a steam wand pressure gauge. The pressure was measuring 1.6 bars and rising when I stopped the process (since something around .8-1.0 is "normal," I thought it would be wise )

2) I assumed that the soft boil I was hearing after shutoff was residual (at this point, I'm familiar enough with lots of little sounds in boilers to NOT assume the worst). This morning, though, it occurred to be that there is an easier way of checking this. I could hear the constant (not intermittent) soft boiling continuing for almost 10 minutes after the Pstat clicked off. Then, I turned off the power switch. Immediate silence. I repeated this (turned it on, soft boil began again, despite the fact that the Pstat was not turning the boiler on), turned off the power -- immediate silence. SOMETHING WEIRD!!!

On this point, if I understand the electrics of the Cremina (I probably don't), I would have thought that, once the Pstat reached pressure and forced the microswitch to "click" to the "off" position, then it would have been impossible for power to find its way to boiler, so, last night, again, I broke out the multimeter and checked the microswitch in the Pstat -- again, the ohm-reader showed C (to use OE language) when in the heating position, and NC when I manually compressed the Pstat bar onto the microswitch. I also rechecked the element itself -- it is showing a stable reading of 15.5-ish. Now, I know that this is higher than the 12-ish that is mentioned, but, I'm using a pretty cheap multimeter (hope to double check everything tonight with a better one), so, I can see the calibrations a bit off. The key is that the reading is stable (no fluctuations).

3) The Cremina does NOT need scaling. All was torn down (the boiler was opened), descaled, and rebuilt over the last 2 weeks. This included descaling -- very carefully, using a syringe to administer drops of a 50/50 vinegar/water solution into the opening -- the Pstat.

4) The microswitch is definitely making the click. The whole machine is exposed at this point. I have gone through this process about 15 times, tweaking things each time, and it is definitely clicking. It is also evident (beyond the boiler heating indicator light, which I wouldn't trust alone) because the STRONG boiling stops at that point, and the machine shifts to the "soft boil" sound at that point.

Now, I have no idea if it is possible for the microswitch to "click" and still be faulty in some way beyond that. I was wondering if there is any way that there could be a "short" or something within the microswitch that is allowing a small amount of power to continue to pass through to the boiler. I keep thinking that the microswitch is an obvious suspect, here, but, it seems to be passing all of the tests, so ...

FYI, I wasn't sure how a microswitch worked, so, I watched this video, which was REALLY helpful and I strongly recommend it to anyone who is learning/teaching about this.

http://www.youtube.com/watch?v=q6nP1FjxAMU

As I've said, I'm getting "normal" readings when I put my multimeter on it.

But ... and this could be critical ... I'm wondering about one thing. Using the the multimeter, I'm following the OE instructions here http://www.orphanespresso.com/Olympia-C ... 565-1.html to test across the two OUTSIDE bars of the microswitch (leaving the middle one alone) and all works correctly. However, just for laughs, I hooked up the multimeter to the two bottom bars coming off of the microswitch. When I do that WITHOUT depressing the Pstat bar, I get a NC. When I manually DEPRESS the Pstat bar, while testing those two "bottom" microswitch bars, I get an ON (C) reading. I feel like that shouldn't be the case, so, I'm wondering if that might be the cause of the problem, but, I haven't been able to find anyone talking about that on the HB forums (I've probably missed it, though).

5) The question about the Pstat being set too high was one of the first things I tried to work with. As I said in the original post, I don't know the history of this machine, so, I'm not trusting any of the original settings (or wiring, a point I will get to below) on it. When this problem first started happening, I started to reduce the setting, assuming that I could get it to the point where the pressure would be so low that I could use that as a "zero point" from which to diagnose everything else. Turns out that, no matter how low I set the pressure, the problem persists.

6) I went through all of the contacts and wires last night -- AGAIN! -- and everything is solid.

All of this leads to the issue of wiring. When I took the machine apart, I went through the overkill documentation process to assure that all of the wires went back in the right places: a hand drawn diagram and MANY digital photos to have a second diagram in order to confirm everything. All of the wires are back in the same place I found them. HOWEVER, because (as I noted in the original post) this problem MIGHT have been a problem in the original condition that the machine came to me, I'm wondering if any of this might be explained by the original owner having switched around or messed with the wiring. So, in the interest of full disclosure, here are pics/drawings of the wiring set up ...









Sooooo ... thoughts?

Without going into great detail, do you have another pressure switch to swap in? If not, is the microswitch defective? They can be replaced.

I do not have a Pstat to switch out/swap in.

I guess, I'm trying to figure out if the multimeter readings I received might indicate the microswitch is defective (see #4 from my last post in this thread). I'm just not sure if the multimeter readings do or do not indicate it is defective. I definitely need some input on that one since that is the most obvious unexpected/strange finding out of everything I've observed.

soonerspresso wrote:However, just for laughs, I hooked up the multimeter to the two bottom bars coming off of the microswitch. When I do that WITHOUT depressing the Pstat bar, I get a NC. When I manually DEPRESS the Pstat bar, while testing those two "bottom" microswitch bars, I get an ON (C) reading.

Not sure I understand -- are you getting continuity between the two terminals at the right side of this picture?


If so, something is amiss. That top pin (called the Common pin) should have continuity with the Normally Closed pin (yellow in the picture) when the pstat is not under pressure, and continuity with the Normally Open pin (lower one in the pic) when the pStat opens. There should never be continuity between the NO and NC pins, so I'm thinking your pStat switch may have a problem. If it truly is allowing a small amount of current to flow into the element when the pStat is off, I would expect it to heat up and melt soon. Probably time to buy a new pStat, or perhaps just the microswitch if you can find one.

P.S.
I hope you are running this on a good GFCI - always a good idea on these machines and especially if they are misbehaving. If you are running it with the case open do be very very cautious - household voltage is more dangerous than many people think - it can and does kill people.

If you have a Kill-a-Watt meter, that might be one way of testing this machine. It would tell you how many watts it is pulling as the pStat is switching off and you are getting that 'soft boil.' In my town you can check a Kill-a-Watt out from the local library.

It is hard to diagnose electrical issues remote from the machine but....

Generally, trust the C /NC ohm readings on whatever meter. You are basically checking on/off behavior of the switch and in the Cremina each component is a switch. How is the indicator light behaving? Does it turn off w pstat? You can do a lot of tests with a short pigtail wire...with a male spade to n each end to bypass switches and observe the circuit behavior. With this bridge wire you can remove elements from the system and it observe result. When you bridge a switch it removes that possible defect from the circuit so by elimination you can tick off the good/bad question of each switch as it relates to the circuit.

Follow the circuit and pose if/then scenarios to logic it out. The problem here is fundamental. You can do all tests with the machine unplugged so if the is some phantom circuit it will not shock you.

Your wiring diagram looks correct. The brown wire as HOT and blue is NEUTRAL, Is your wall box wired correctly so that brown is indeed hot?

15.5 ohms seems high. What is resistance of the entire circuit measured at the plug? In other words, is the a second resistor apart from the element somewhere in the circuit?

Remain calm and do the checks but don't rule out things like the power cord or the box or the wires themselves....a lot to f things can get changed over the history of a machine so, assume nothing and avoid diagnosing with parts. But do check/bridge/test one switch at a time and trust your results until you narrow down the problem to whichever component is at fault.

homeburrero wrote:Not sure I understand -- are you getting continuity between the two terminals at the right side of this picture?
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If so, something is amiss. That top pin (called the Common pin) should have continuity with the Normally Closed pin (yellow in the picture) when the pstat is not under pressure, and continuity with the Normally Open pin (lower one in the pic) when the pStat opens. There should never be continuity between the NO and NC pins, so I'm thinking your pStat switch may have a problem. If it truly is allowing a small amount of current to flow into the element when the pStat is off, I would expect it to heat up and melt soon. Probably time to buy a new pStat, or perhaps just the microswitch if you can find one.

P.S.
I hope you are running this on a good GFCI - always a good idea on these machines and especially if they are misbehaving. If you are running it with the case open do be very very cautious - household voltage is more dangerous than many people think - it can and does kill people.

If you have a Kill-a-Watt meter, that might be one way of testing this machine. It would tell you how many watts it is pulling as the pStat is switching off and you are getting that 'soft boil.' In my town you can check a Kill-a-Watt out from the local library.

Okay, I believe that this (hopefully) is solved, then. As I wrote before, I AM seeing continuity between the Normally Closed and the Normally Open pins WHEN I manually depress the Pstat (pstat? pStat?) to simulate it under pressure. 1st Line has the microswitch available for around $50, so, I will purchase a new one assuming all of this is correct ...

I appreciate all of the warnings about electricity. I didn't realize that this was an electric problem until I put the new pressure valve in and saw the same problem emerge -- I knew something electrical must be happening, so, I've taken extra precautions moving forward.

Finally, before I drop the money on a new microswitch, it occurred to me (I hope you can hear my hand slapping my head ... and the Homer Simpson "D'Oh!") that I DO own an older (and fully functioning) Pasquini Livietta with this kind of a Pstat, so, I'm going to try to switch them out (hopefully, everything is compatible ...?) and see if that fixes the problem. (Sorry about that, Dr. Gary ... it just slipped my mind ...).

I'll report back once/if this solves it.

Cheers!

orphanespresso wrote:
Your wiring diagram looks correct. The brown wire as HOT and blue is NEUTRAL, Is your wall box wired correctly so that brown is indeed hot?

15.5 ohms seems high. What is resistance of the entire circuit measured at the plug? In other words, is the a second resistor apart from the element somewhere in the circuit?

1) Whoa ... It looks like, as I checked the wiring on the plug, the blue is going to the HOT prong and the brown is going to the NEUTRAL prong. Before I do anything, does this mean that the POSITION of the two wires -- the blue and the brown coming from the power cord -- as they go into the block matters? Does this mean that the NEUTRAL (regardless of the colors ...) should actually be on the LEFT and the HOT (regardless of the colors) should be on the RIGHT? If so, then, the wiring is INCORRECT.

Please advise on this!

2) I'm going to double check the 15.5 ohms reading with a better (non-Harbor Freight, if you know what I mean ... ) multimeter tonight when my wife brings home a better one from her lab. I'll get back on that one ...

Thanks, Doug. As everyone says, we would be lost working on this machine without all you and Barb have done!

My simplest approach is to follow the circuit along the hot wire beginning at the wall box. If a polarized socket the small flag of the plug is hot and should be on the right in the box with corresponding hot wire of your house circuit. The path then is hot to the power switch, through a he switch, to the pstat, through the thermal safety, On to the element. After the element (load)' I (likely incorrectly) think of as the neutral side of the circuit which returns to the neutral side of the switch and pilot light. So it is one big loop with a bunch of switches and one load. The lights count as a wire not a switch and are always closed. So if all the switches open and close properly your problem can only be some sort of mis wiring, which could include a bad light.

Verify proper function of all the components and keep tracking nag the circuit along the hot route and I am sure something will pop up to clarify your issue.

Hope this helps.