Steam boiler keeps heating up, even on standby

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thebearmaster
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Steam boiler keeps heating up, even on standby

Post by thebearmaster »

Hi,

On the latest turn in my attempt to fix my steam boiler (first documented here: viewtopic.php?f=57&t=2261) I have managed to replace the heating element with a trickily obtained replacement part (110v), put the lid back on, put all the wires back in place and... now the steam boiler's heating up. In fact, I now have the opposite of the problem I had before -- the steam boiler won't stop heating up.

Observations so far:
- The steam boiler heats up even when the machine is on standby.
- The steam boiler pressure gauge goes up well into the red, and eventually sets off the relief valve. This repeats until I let out water or steam to drop the pressure, or unplug the machine.
- Neither the 15A / 20A setting, nor the econ mode, makes any difference.
- All the while, group functionality works fine.
- I don't hear the fan that I thought would spin without exception when the steam boiler used to heat up.
- There is no alarm, blocking or otherwise. In particular the one called 'damaged boiler heating element triac / SSR', mentioned in section 5.6 in the manual https://www.chriscoffee.com/v/vspfiles/ ... Manual.pdf is not triggered. This is even when I work around overpressure and consequent relief valve operation, by 'bleeding out' some steam through the steam wand, which together with the malfunction would mean that the heating element would be constantly on.

From previous posts on this invaluable forum, I think my problem is down to either a faulty controller board, or a faulty triac.
- Since I don't hear the fan which I read is controlled by the controller board, it makes me suspect the controller board.
- On the other hand it seems odd that group functionality is working fine. Is the controller board designed such that steam boiler-related functionality is entirely isolated?

My questions to the experts:
- Is it possible that the cause is due to something other than the controller board or the triac?
- Specifically, could I have caused this malfunction by making a mistake putting the wires back on? Is there any polarity with the heating element that I could have gotten wrong? Something I could have done that made the temperature probe malfunction?
- If not, how can I narrow down the faulty part between the controller board and the triac? This is important to me because sourcing parts for the 110v machine here in Europe is by no means trivial.

Again I await your pearls of wisdom.
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chas
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Re: Steam boiler keeps heating up, even on standby

Post by chas »

It sounds like the triac board to me. Since both triac boards are identical, you can swap them or just swap the wires if they are long enough. If the triac is shorted on, you will now have the problem with the coffee boiler rather than with the steam boiler. Then you will know to order a new triac board. They're about $40US before shipping.
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chas
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Re: Steam boiler keeps heating up, even on standby

Post by chas »

BTW: In order to minimize the current draw in 20A mode, the group boiler heats up before the steam boiler even turns on. That way you don't have a 10-15 minute period where both boilers are drawing current constantly. Therefore, the unit is normally on for 10-15 minutes before the controller board turns on the steam boiler and the fan. This is why you never hear the fan coming on. If the steam boiler comes on even in standby it almost has to be the triac board.

Even though the triac failure alarm should come on if the steam boiler temp exceeds 140C, I think the pressure relief valve often pops off before that temperature is reached.
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thebearmaster
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Re: Steam boiler keeps heating up, even on standby

Post by thebearmaster »

chas wrote:BTW: In order to minimize the current draw in 20A mode, the group boiler heats up before the steam boiler even turns on. That way you don't have a 10-15 minute period where both boilers are drawing current constantly. Therefore, the unit is normally on for 10-15 minutes before the controller board turns on the steam boiler and the fan. This is why you never hear the fan coming on. If the steam boiler comes on even in standby it almost has to be the triac board.
How about after the group has reached the set temperature? I'm not hearing the fan even after the group temperature is reached -- I was expecting to hear the fan come on but there's no sound.

I will try to switch the wiring for the triacs since this sounds like a definitive means to diagnose the faulty part. Looking kind of hard to get into that part though...
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chas
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Re: Steam boiler keeps heating up, even on standby

Post by chas »

The fan plugs into the Triac board. Usually when the board fails it's due to the triac itself. However, I suppose other parts could also fail on the Triac board which might affect the fan operation as well.

If you haven't already swapped the triac boards you can always start by unplugged the cable from the controller board at the triac board and see what happens. If the problem continues then it is not a controller board issue. If the problem goes away then it definitely is a controller board issue. BTW: historically this issue is the triac board 99.9% of the time
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Re: Steam boiler keeps heating up, even on standby

Post by thebearmaster »

chas, thanks for that tip. I've disconnected the cable just above the cable that goes to the fan (marked 'P1' in the triac connection diagram in the manual s1v2/V2%20Manuals/V2Owner'sManualRevH.pdf) and confirmed the steam boiler heats up.

So I guess that settles it... it seems to be a bad triac board. Now just need to figure out how to get the 110v part in Europe, and how to do the replacement.
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Re: Steam boiler keeps heating up, even on standby

Post by thebearmaster »

I'm getting a quote of ~$80 shipping for the part from Chris Coffee. Aside from the monetary expense, this will get me past the customs allowance and trigger quite a bit of hassle and additional expenses to bring it over here. And the irony is that next week I'll be in Italy for vacation, not too far from the La Spaziale factory...

Would it be a bad idea to try to locate the faulty electronic part on the triac board and attempt a repair? Would be most grateful for any info on repairing (cf. replacing) the triac board.
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chas
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Re: Steam boiler keeps heating up, even on standby

Post by chas »

Most of the electrical components such as the motor, heater elements, controller board, and solenoids show separate part numbers for 110v and 220V versions. However, the parts list only shows one part for the triac board so I am guessing that if you can find a local source for one in Europe it will work in your machine.
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Re: Steam boiler keeps heating up, even on standby

Post by MGearig »

If your fan fails and the steam boiler is on long enough, that triac will overheat and produce the symptoms the OP describes. In my case, once it all cooled down, it continued to work normally. I suspect the integrity of the triac has been compromised, though.
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Re: Steam boiler keeps heating up, even on standby

Post by thebearmaster »

Reporting back: there was no sign of damage on the triac for the steam boiler when I took it out. Since it proved to be difficult to obtain a replacement triac here in Switzerland, I took a gamble and asked a friend who has an electronics hobby if he could try to find and replace the faulty part.

My friend's electronics foo was not sufficient to confidently narrow down the faulty part on the triac, so we decided to test the assumption that the transistor had blown, since it looked like the thing most vulnerable to heat damage.

I couldn't get an exact replacement for the transistor, so went for the closest available one -- the rating after the '-' in the part number was a little different (600 vs the original 700). We then had a lot of difficulty melting the solder holding the old transistor to the board. My friend's fairly fancy soldering iron was not really melting it well even when set to the hottest temperature. In the end we decided to snip the legs off, and solder the replacement transistor onto the legs.

And to our relief, we guessed correctly. The home-remedied triac is doing its job for over a month now. So this repair saga has come to an end.

Thanks everyone for your kind suggestions while I was fumbling my way out of the mess. It feels great to return to my usual alertness levels in the mornings.
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