Isomac not heating up after initial warm up.

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
boublanc

#1: Post by boublanc »

Hello My Isomac Tea will work for 1/2 hour then the power no longer reaches the boiler's element. The power on light work, both boiler on/off (red/green) light are not coming on... PSTAT is working, the green light on the the power relay does come on but I get only 19V at terminal A1(+) 0V at terminal L1. If I disconnect terminal 5 from the Giemme controller it does show 120V but plugged in the the relay I read 19V at the relay??? After the machine cools off for 15min the auto fill kick in and the boiler's element does get power and heats up. Terminal A1(+) gets 120V. What should I check next or do you have enough info to say if the controller is failing?

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erics
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#2: Post by erics »

You have read this? - Isomac Millenium... Pressure Gauge Problem

Michael Teahan gives some good advice in that particular thread. The key question would be whether or not the autofill still works when the machine powers down after ~ 1/2 hour.
Skål,

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

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boublanc (original poster)

#3: Post by boublanc (original poster) »

Thank you Eric for the link as it does describe my situation. and hard wiring the relay came up in there.
Hard wiring the relay A1(+) is something I did while i was troubleshooting the problem, and the element did get power. I was hoping this would pin point the fault to either the relay or the controller. But unfortunately the fact that pin 5 on the controller is reading 120V when the machine goes down but if it is (pin 5) plugged in to A1(+) it only read 19V I got confused, I thought that the relay was doing something weird...
So I will go back to diagnosing and will see if I hard wire the relay something else is not working or if it does fix the fault....

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erics
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#4: Post by erics »

I'm going to have some disjointed thoughts below but unfortunately, it sure seems as though the Giemme controller is at fault. The question would be what part of the controller - likely the transformer - but that can be proved with a very high degree of confidence.

Sure, you can hard wire the SSR (terminal A1) and the machine should heat up just fine and everything will APPEAR OK BUT . . . when all is nice and toasty, the autofill may not function because the transformer which powers the DPST relay has failed. The way to test that is to have the machine die on you and then disconnect the lead from the water level probe. Autofill should start and will run as long as you leave the probe disconnected. If it does not, the transformer is in a failed state.

The SPST controller relay that powers the SSR via pin 5 is energized via the transformer anytime the machine is on. IN OTHER MACHINES, the energizing of this relay may be defeated by a low water reservoir level or some other fault - BUT NOT YOURS.

Yes, the 19V would confuse me also.
Skål,

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

coffee_monkey

#5: Post by coffee_monkey »

You might have a transformer on the Giemme board dying. My Rituale had this problem a couple years back - it will heat up and work for about 30 min until the machine (and the controller) warms up, at which point the transformer will stop working and stop outputting the proper voltage to the element. I could not find the exact surface mount transformer from the original board, so I wire a external one instead. Fortunately I had plenty of room to do it as I plumbed in my machine at that point....

See more about this problem here:

Trouble with an Isomac Rituale
My Giemme control box fix
Ben Chen

boublanc (original poster)

#6: Post by boublanc (original poster) »

Well I was able to pull shots all morning! :D
The machine was on for 3 hours, everything is working as usual, auto fill and all. I will now order a new control board and in the mean time, I can still enjoy my morning coffee!
I do treat the "hard wire" solution as a temporary fix. As far as replacing the transformer, I would not know where to start to source such a part, I live in a small town (5000 peoples) that sit 3 hours drive from big center with electronic shop where I could find help/parts. Not to mentioned That I am not sure the problem is with the transformer or with one of the relay in the control box...
If anyone has any suggestion on where to find replacement transformer or relay, I would be interested in attempting to fix the old control box once I get the new one. It would be great to be able to fix the unit as their failure appear to be quite common, and expensive to replace...
Thank you guys for your help
Marcelin

boublanc (original poster)

#7: Post by boublanc (original poster) »

Correct me if I am wrong, the transformer provide 18V to power the relays who will open or close the electrical circuit and allow 120V to flow through. As there is 2 relays and only one function is failing, one of the relay would be the culprit, not the transformer?...
I understand that this type of common sense is not always right with electronic circuits. So let me know if I am out to lunch on this. :?:
Thank you

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erics
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#8: Post by erics »

You are NOT out to lunch.

One relay is a single pole, single throw (SPST) which sends 120vac to pin 5 and thus the appropriate terminal on the SSR. The other relay is a double pole, single throw (DPST) which sends 120 vac to the pump and the boiler fill solenoid (simultaneously) when the boiler level probe "says so".

If the ONLY component that is failing is the relay for pin 5, then I see no problem in disconnecting pin 5 and providing 120 vac to the SSR as you have done. Naturally, it would be nice to get that power from the main power switch.

At this point, I would not replace the controller unless I came across one at a machine junkyard or equivalent.
Skål,

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

boublanc (original poster)

#9: Post by boublanc (original poster) »

Thank you Eric, priceless to have people like you in here.
Marcelin

danaleighton

#10: Post by danaleighton »

I sourced that transformer part when my control box went out. It turned out not to be the transformer that was bad -- one of the relays inside the Giemme box was sticking (open or closed I can't remember). Those were just too hard to get out and so I replaced the box instead.

The transformer is made by Zettler Magnetics in Aliso Viejo, CA. Their part number is BV301S18015 which matches the markings on the original part in the Giemme box. A photo of the new part (red on the left) and original (green on the right) is below:

I verified with a rep at Zettler that their part was the correct replacement part. It can be ordered from a couple vendors for about $3 plus shipping. Here's a link to their PDF spec sheet: [url=http://www.zettlermagnetics.com%2Fpdfs%2FBVseries.pdf&ei=AhBOTP76HMOcnAe1trjYCw&usg=AFQjCNH2ayavhcjW6VxAix2vI1MUes3bSA&sig2=Q4Xg5zs6ymoRnmBVljtrlA]click here[/url] and the Octopart page for it: click here

So now I have 2 - the old one and the new one, and am saving them in case it goes bad on the new control box. :)
Dana Leighton
LMWDP #269