Orphan Espresso

Home > TECH TIPS > Olympia and La Pavoni Shorted Heating Element Repair
 

Olympia and La Pavoni Shorted Heating Element Repair

Both Olympia and La Pavoni home espresso machines have the type of heating element which has the Cal Rod coil affixed to a solid bottom plate which forms the base of the boiler.   This conformation of the element terminals can suffer from a short circuit at the end of the element at the interface with the brass plate ( heating elements installed with threaded nuts are not as prone to this short).   The original installation of the element in the plate is finished with the use of glyptal (an electrical sealant and insulating paint) and ceramic beads.   It is not uncommon for the insulating paint to wear over time allowing moisture to enter the rod ends causing a short at the plate....this is particularly an issue if the machine has a leak or leaks which directly flood the bottom plate, or the element was submerged in water while cleaning or rebuilding the machine.   The operational indicators of this short is generally the "popping" of a circuit breaker or GFI plug, the non function of the heat cycle, or even an electric shock felt by the operator.   The first response to a non heating element is to assume that the element is "burned out".    Yes, an element CAN be "burned out" with a discontinuous resistor inside the sheathed heating rod or dead short somewher in the coil itself, but 9 times out of 10 the problem is a surface short at the ends of the rod caused by water entry and degradation of the insulating material at the ens of the rod at the junction with the brass boiler bottom plate.      The following is a guide for diagnosis and repair of this very common problem.

DIAGNOSIS OF A REPAIRABLE HEATING ELEMENT SHORT

Diagnosing this electrical problem can be done with the element on the boiler by simply removing the wires to the two heating element terminals and proceeding with some simple test readings using a multimeter.   The following procedure was carried out with the heating element removed from the machine and thoroughly cleaned before testing and repairing.  
The machine in this example is an Olympia Cremina but the same process holds for all Olympia machines as well as La Pavoni Europiccola and Pro models.

1.  Check the resistance of the element by setting your meter on OHMS and placing the probes on the element terminals.




This test should give a stable reading (for a Cremina 12.5-12.8 ohms) but most important is that the reading is STABLE......if this reading wanders and fails to stabilize this may mean that the element is actually burned and cannot be repaired.

2. Place one test lead on  a terminal and the other on the base plate making sure you have a good contact.


ANY resistance reading from the terminal to ANY other part of the element base or coil indicates a short.   Generally the ohm reading wanders and fails to stabilize.




These two reading taken together indicate a repairable electrical short caused by water at the terminal ends.    You may have perfect looking ceramic bead insulators  but trust me, under those beads is a bit of water, some degraded sealant,  and the source of your machine failure.      To repair this short we first remove the offending degraded material, then dry out the water, and reseal.   Simple!    Here's how you do it.

Break off the ceramic beads with a pliers or similar tool.



Remove any crumbling or obviously degraded material from the inside ends of the heating rod.  This material is usually reddish brown and if it is crumbling remove all of it until you get down to solid material inside the rod.



When the ends of the rods are cleaned out bake the element in a hot oven for a few hours to drive out any and all moisture.



After "kilning" the element test both the terminals and the terminal to base resistances to see if you have cured the short.



SHORT CURED!!!!!!!!





NO SHORT HERE EITHER!!!!!!

You can test the element while it is hot (with care) as you proceed.   You may need to pick out more crud from the rod ends and kiln some more but eventually you should be able to drive out all the moisture and have a stable element ready to rebuild.

We use a kit composed of high temperature epoxy, glyptal, and teflon collars to rebuild the terminals.



Cut off a piece of the epoxy putty and work it into a ball and then a worm shape.    This epoxy acts to stabilize the terminals  and insure that there is no touching of the inner element wire to the rod casing.   Using a probe, work it into the rod all the way down and then dress it off on top even with the heating rod ends.













Test with your meter as you go along just to make sure all is well with the process.



After the high temp epoxy has cured (30 minutes or so) the glyptal can be applied to seal the ends of each of the terminals of the element.    Shake or stir the glyptal and apply with a toothpick making sure the entire rod end is covered and sealed.    Going over the edge is fine (you can see the shadow of the original glyptal so there is no reason to be ultra conservative with it but to me neatness counts so we just seal the ends and don't slop it around too much).







The glyptal completely cures in 24 hours  and then we dress the terminals with their teflon collars, installing them with a snap ring plier and gentle persuasion.





One last check.






HOW SWEET IT IS!!!!!!!

















Copyright 2014 Orphan Espresso.