I'm no electrical wiz, but I have some basic diagnostic skills and am plenty comfortable opening the machine up (have replaced a pump & thermostat previously). Looking for a little advice on what might be wrong and/or what else to test. Machine is ~7 years old, used for a couple pulls per day, nearly every day. Powers up OK, pump runs, no heat no how.

Also interested in knowing what maintenance/tweaks might be worthwhile to do while I have it open. The new pump (Ulka, replacing C.E.M.E.) is just a year or so old, or I'd be doing that. I've heard there are replacement thermostats to help with the deadband? Not really interested in undertaking a PID, though I might be convinced otherwise. Descale (it is solution descaled once in a while...anything easier with it apart?). Gasket replacement (no leaks currently)? Anything?

Any assistance appreciated!

Here's what I know:

Both thermic fuses (that I am aware of) still have continuity. One is just a length of low-temp solder, the other is a real thermostat (no reset button). I don't know if these are brew/steam, or if the wire one is a safety and there is a third elsewhere. They are both located atop the boiler. The plastic connector covers on the non-wire one were black and melted looking.

Heater coil shows ~8 ohms resistance across the terminals.

No heat in either brew or steam mode, and I'm pretty sure that the 'heater on' indicator light is not lit when in brew mode but does come on when steam is engaged.

Here's a pic of the top of the boiler, fuses dead center. Red cloth looking insulation covers the 'solder' fuse, brown dealie right next to it is the one with the cooked terminal covers (which cracked away when I removed the connectors):

I think your machine has 3 thermostats:

• capillary-type brew temp thermostat (probably has an adjustable dial along with a bulb sensor dropped into a thermowell on top of the boiler)
• steam thermostat (probably the one on top with the burned connector)
• safety thermostat (fusible link)

The crimp connector on the wire at the steam thermostat needs to be replaced. Overheating was probably caused by high connection resistance associated with loosening of the connector's grip on the thermostat tab. It is possible that this is the only problem. The brew and steam tstats are in series, so the circuit through the steam tstat must be conducting for the heater to run.

Jim

yes, a bit more reading would seem to indicate that the zaffiro has a habit of popping brew thermostats. i do see that as a 3rd device, as you describe. it would appear that there is continuity through that one as well...

what is a better replacement? i see the chris' version, but i hear that it does not improve the deadband. what about the minco, here?
http://coffeegeek.com/forums/espresso/machines/196054

alright, so no further advice?

i have continuity through all three thermostat/thermofuses, 8ohms resistance across the heater terminals, but no heat.

what's my problem?

Likely a bad connector that is not making contact.

!!! WARNING !!! Lethal Voltages

Measure the voltage drop between the power inlet and each point in the circuit.
The voltage should be near line voltage until the neutral end of the heater.

If you don't understand the above, DO NOT ATTEMPT !!!

dookie wrote:alright, so no further advice?

Unless you have already replaced it, as I wrote previously, I would consider that blackened connector to be the prime suspect.

Jim

so i replaced many connectors...anything that looked the least bit toasty. that got me heat at least, but not proper heat. in brew mode, the element cycled on only briefly and the water barely warmed. steam seemed fine.

thermostat, right? so i bought the minco non-pid controller system mentioned in another thread. it is in (and rather cleanly, if i do say so), but something still ain't right. the controller and relay are working fine...120v across the AC side of the relay when under temperature, as expected...but no 'heat on' panel light and no voltage at the boiler terminals. steam works fine, heat light and all.

ideas?