Author Topic: Ground faults  (Read 2946 times)

Offline steveowc

  • GUG Regular
  • ****
  • Posts: 68
    • Old White Coffee with Steam Knob on Front
    • Hario Skerton with Stepperless Mod
Ground faults
« on: November 25, 2017, 06:01:52 AM »
I’m getting a repeatable ground fault — GFCI trips — a few minutes after turning the OWC on or refilling the boiler after a shot/americano.  Based on a little googling, I dried out the boiler/heating element for a few days.  No luck.  Any thoughts?  Could I be overlooking an external leak?   Losing hope here, started checking CL for used Classics.   :'(

Offline SusanJoM

  • Administrator
  • Grizzled GUG Veteran
  • *****
  • Posts: 2410
    • Classic
    • Compak K-10
Re: Ground faults
« Reply #1 on: November 25, 2017, 10:26:14 AM »
I have the utmost respect for the Classic (as long as it's one with the aluminum/brass boiler and not the stainless steel wannabee Gaggia), so I encourage you to look for one of those.  However, you are so close and you have done so much good work on this elder statesman of the Gaggias that I hope you keep it up and at least keep it.

That said, I think the next step would be to grab a multimeter and check the continuity through the entire machine.  Start where the electricity enters the machine and check all the way through until the end.  Unless I'm totally off base (and it has happened many times, I assure you), somewhere in there you will find a fault which you can attend to.

Still....find a reliable machine for your daily fix or you won't have the attention span needed to fix the OWC   8)
“Not everything that can be counted counts, and not everything that counts can be counted.”
Attribution in Dispute

Offline steveowc

  • GUG Regular
  • ****
  • Posts: 68
    • Old White Coffee with Steam Knob on Front
    • Hario Skerton with Stepperless Mod
Re: Ground faults
« Reply #2 on: November 25, 2017, 10:45:09 AM »
Ha ha I hear you about the daily fix!  I should have added that I disconnected one of the leads to the heating element and there was no ground fault, so I suspect it's the culprit.  After the machine warmed up this morning, there weren't any further faults, so I have a new theory -- the boiler gasket is the original and it's leaking steam under the initial pressure.  New o-rings on the way (found a good thread here about that) as is a multimeter (I need the multimeter for other projects anyway).  Thanks for the encouragement! 

Offline steveowc

  • GUG Regular
  • ****
  • Posts: 68
    • Old White Coffee with Steam Knob on Front
    • Hario Skerton with Stepperless Mod
Re: Ground faults
« Reply #3 on: November 27, 2017, 06:28:54 PM »
Multimeter arrived. Quick check of heating element terminals against boiler showed infinite resistance, which is a good start. From what I read, there can be pinhole leaks inside the boiler.  Another clue — I think the ground faults may correlate to the boiler thermostat turning off after the initial warm up, although it’s not easy to be sure because the power cuts out.  More systematic tests will have to wait a couple days.

Offline steveowc

  • GUG Regular
  • ****
  • Posts: 68
    • Old White Coffee with Steam Knob on Front
    • Hario Skerton with Stepperless Mod
Re: Ground faults
« Reply #4 on: November 30, 2017, 07:27:42 AM »
I’m not finding any connections to ground when the machine is cold. I tried eliminating the brew tstat from the equation by turning the machine on with the steam switch on.  This still resulted in a ground fault, so the brew tstat is not to blame.  I did hear a hissing just before the fault, so I think water/steam is escaping the boiler and causing a short or connection to ground.  From what I (dimly) understand, both of these can cause the GFCI to trip.  So I’m optimistic that a new gasket along with making sure the boiler mating surfaces are smooth will fix the problem. 

Offline steveowc

  • GUG Regular
  • ****
  • Posts: 68
    • Old White Coffee with Steam Knob on Front
    • Hario Skerton with Stepperless Mod
Re: Ground faults
« Reply #5 on: December 10, 2017, 10:08:28 AM »
I've replaced the boiler gasket -- the one from the "O-Ring Store" mentioned here:

http://www.gaggiausersgroup.com/index.php/topic,1223.msg13219.html#msg13219

seems to work well.  However, the GFCI still trips when the OWC warms up initially, and just about at the point when the brew tstat would go off -- in other words, when the water has at least reached boiling (95 degrees C at my elevation).  I think what may be happening is that differential thermal expansion is allowing a leak.  For example, the boiler body could warm up before the OPV, potentially creating a gap where the OPV attaches.  I replaced the OPV gaskets, as well as adding small gaskets to the copper tube that connects the boiler with the steam valve, with no luck.  But I tested my theory this morning by turning the OWC on for 30 seconds, then turning it off for a couple minutes to let the heat distribute.  Then turned it back on -- no GFCI trip!  Similarly, if I turn the OWC off and turn it on again within an hour or so, while the metal is still warm, no GFCI trip.

The only other points at which I think steam/water could be escaping are the two brass right angles into the boiler body, and the steam valve.  Am I missing any?  I think it's likely the steam valve because I can also get a GFCI trip after steaming milk and closing the valve.


Offline steveowc

  • GUG Regular
  • ****
  • Posts: 68
    • Old White Coffee with Steam Knob on Front
    • Hario Skerton with Stepperless Mod
Re: Ground faults
« Reply #6 on: December 10, 2017, 10:13:25 AM »
Oh yeah, maybe the place where the solenoid/three way valve mates to the boiler body could leak, but that seems unlikely.

 

LIBRARIES

Reference Library

Owners Manuals, Parts Diagrams, Wiring Diagrams, and How-To-Do-Stuff Articles.

 

+-Recent Topics

The Forum is Shutting Down, closing as of Jan 1, 2018 by SusanJoM
December 31, 2017, 08:39:24 PM

Coffee Deluxe by SusanJoM
December 31, 2017, 11:47:12 AM

(Questions) - Homemade pressure gauge for adjusting pressure by SusanJoM
December 29, 2017, 03:19:19 PM

Nice OWC restoration at HB by D4F
December 27, 2017, 04:27:49 PM

Pump leaking from plastic by wjm
December 24, 2017, 05:37:39 PM

Using Thermoblock as preheater by jerryseabridge
December 24, 2017, 11:00:25 AM

Use OWC OEM portafilter for DIY pressure and/or temp gauge? by rcfitz86
December 22, 2017, 03:02:00 PM

Classic, solenoid or pump issue - help needed! by DG Classic
December 15, 2017, 11:32:58 AM

Gaggia Classic Solenoid Spring Question by SusanJoM
December 15, 2017, 10:59:51 AM

Dosing on Gaggia Classic Stainless Steel boiler by benm
December 13, 2017, 06:15:59 AM

Powered by EzPortal