Guys, experts, experienced veterans, engineers, helpful people,

I need your help once again. I've dug around for days trying to find an answer, but am really struggling to find action steps I can take. I've already read everything here http://www.home-barista.com/search-results.html?q=%22not+heating%22+boiler&ie=ISO-8859-1&cof=FORID%3A9&cx=partner-pub-1874394195286019%3Aih80ev-qwtj&sa=Search&siteurl=www.home-barista.com%2Fforums%2Fsearch.php#1114. Literally everything. Just kidding. The first two pages (20 topics).

I have a BUNN ES1A http://www.bunn.com/pdfs/commercial/manuals/10712.0000.pdf. It is an older HX machine made by Quality Espresso, which from my understanding is the current producer of Futurmat, Gaggia, and maybe a few other brands. I run my water from a 5 gallon bucket hooked to a Flojet, which I fill with Culligan water at Whole Foods. I bought it rebuilt and have used it happily for 8 months. No leaks. Hooked to a surge protector and PIDed (so no pressure gauge). All was well. Until recent days.

Recently the machine began to have difficulties with heating up too much, to the point where my PID would read about 267 and I am guessing it would trip a safety mechanism, because after that the machine would completely cool off. (In normal circumstances the machine is turned on, it overheats a bit past the set PID point, comes back down, and stabilizes...)

Now, the machine will turn on, pump water, refill boiler if I tip the machine, but it will not heat up at all. The unit remains on (hence still being able to pump...), but no heat. A week ago, sometimes I would turn it on and it would not heat, but other times it would heat. Now, it does not heat at all.


I'm assuming that because the machine is older, it does not have a red reset button for a safety switch (I can't find it, but admittedly am not 100% sure where to look...a picture is worth a thousand...).

I'm also concerned about false pressure, a concept I've just now read about after the countless hours I've spent reading about these machines. But since I have a PID, another_jim pointed out that "A temperature PID would not be fooled and would not need a vacuum breaker." Either way, I've never cracked the steam wand before proceeding with making coffee.


How do I find the fuse that protects the boiler to see if that died?

I know that I may eventually have to check the element, but don't (yet) have a multimeter and don't know what a lead at the element looks like, so if anyone has a picture of that it would prove helpful if it comes to that. Explicit detailed instructions on how to do that would also be helpful.


To conclude, I think what I'm really looking for is a checklist of things to work through, with from easiest and simplest to most complex. I don't want to undertake replacing the element until I've verified that it's not a simpler fix, etc....
I'll then ask further questions about specific tasks on which I am not sure how to proceed.

Honestly, I am a rookie with electronics and plumbing. But I am eager to sit at the feet of the many on this site with great wisdom. Feel free to post many a clarifying question, and I will do my best to furnish further details.

Thank you for all your help,
Kevin

Kevin: I'd start with this: unplug, open the case and do a solid visual inspection. Look at all the wiring, connections (discolored, brittle insulation, loose). Look over all the "black boxes" for similar visual signs. Pay special attention to the heater connections as they are subject to the most wear and tear. If you find anything mentioned herein and are comfortable with a repair of bad connection for example go ahead and read, here and elsewhere advice on proper repair techniques and/or post your findings for more help.
Good luck
Duke Masters

PID'd HX has a lot of electrical and plumbing inside. BEST ADVICE: (based on your comment that "I am a rookie with electronics and plumbing") would be to find someone who knows what they are doing to assist you.

Not knowing the mineral content of that water, nor your maintenance schedule (in regards to descaling), the problem could be a number of things, but since it is refilling the boiler, that is a good sign in regards to the black box and the autofill circuit which includes the water level sensor (which apparently is not scaled).

Now, your problem, based on the over-heat occurrence, and now no heat, could be caused by:
- bad SSR (Solid State Relay) or whatever is used to switch the heating element
- bad PID that never told the SSR to stop sending current
Some or all the following negative effects could have been caused by the above:
- blown or burned out thermal safety fuse
- damaged wires at the heating element from overheating
- bad heating element

Testing most of that is an easy matter for someone familiar with the use of a volt meter capable of measuring voltage and resistance. But those tests can get a fellow all deaded up if they don't know what they are doing, so I hesitate giving specific instructions on the how to.

Here is a pic of your safety thermostats (items 13):



I don't know why they speced out two safeties (redundancy?) but there they are. And, of course, +1 to what KDM and Randy have said.

Do you have a volt-ohmmeter? Do you feel comfortable in using same? Send me an email at the address shown below and I will forward the Bunn manuals to you - perhaps a few pounds of Memphis ribs in return?

Phew been busy lately with the start of the new school year. Alright, back to what really matters...

Thanks so much for all the great advice! I've got all the panels off, the PDF manual open, and have been getting more acquainted with the insides of this machine. Feeling good about all of that.

https://picasaweb.google.com/104807278790460051561/BunnGuts#

I've taken pictures of lots of things, found the safety thermostats, the SSR, and now I think I'm ready to start testing these things.

Will a volt-ohmmeter suffice for testing all of my electrical connections? Just want to know before I drop some cash on one. Also, any links to recommended iterations of said device?

Based on the posts above, I'm seeing that I need to test the SSR and something about the PID (not sure what) to see how they are doing, figure out which one of those guys is the culprit, and then check the safety fuse, heating element wires, and the element itself to make sure they haven't been blown as a result of PID and/or SSR issues.

Let me know if my thinking seems sound, there, if you will.

Thanks!
Kevin

Update:

Multimeter arrived, switched to continuity check, unplugged the machine, disconnected the wires from the thermal fuse and then measured. No beep, which means no continuity. Meter read about 23. Hopefully I did all that right.

Based on that info, do I know the fuse is bad, or could it be the the fuse or the heating element? Is there another test I should do to be sure it is the fuse?

Perhaps most importantly though: I have not had any luck trying to figure out where in the world to buy a new fuse. None of the fuses I've found look like my pictures. So if anyone has a lead on where to find those, I'd greatly appreciate it.

As always, thanks for the ceaseless help. The sense of progress is exciting.

What you are showing pics of are the heating element terminals. I suggest you go here and explore around:

http://dir.groups.yahoo.com/group/BUG-is-Bunn/?v=1&t=directory&ch=web&pub=groups&sec=dir&slk=6

The safety thermostats are (should be) as I pictured previously. Most definitely they should show continuity, i.e. 0 ohms.

Thanks Eric that was helpful.


I realized the problem. Here is my machine. Compare it with the pic you posted above. A few key differences, including the absence of those limit thermostats.



So, is that something that just must be hiding. I'm scouring the boiler and don't see anything that looks like the thermostats I've found using google image and at espressoparts. Unless...

I found this quote at the Bunn User Group.

I don't use hi-limit tstats any more. When I PID a machine I use the Alarm function to control runaway boiler temps. If that fails, the popoff valve is there as a backup.

- Robert Harmon

My machine was PIDed when I bought it, so I'm not certain that this is the case with mine. But I am suspicious. I think if this is the case, then my next step is to check the SSR connections. Yes, the small LED on my SSR is on. It starts off blinking, then just stays on. My PID reads out 78, a believable interior temp. Apart from those little observations, not sure the best way to analyze the SSR.




From what I understand, this picture shows anti-siphon valve (what he referred to as the pop-off valve above?), the expansion (compensation as my manual calls it) valve, and the water level probe, working from top right clockwise around.




Hows my thinking? Learning tons here. Ideas for next step? Maybe the tstats are hiding somewhere, and maybe since it's an older machine they look quite different?

Firstly, during all of this testing, keep the heating element disconnected and the wires which connected to same lightly taped over with electrical tape.

It starts off blinking, then just stays on.

When the machine is powered on, the SSR light should simply come on and stay on when the element is disconnected. Take a pic of the wiring as it connects to the PID unit - the temperature sensor (probably thermocouple) wiring is polarity sensitive as is the ouutput wiring from the PID to the SSR.

As regards your pic, you have (top right & clockwise) the boiler safety valve, anti-syphon valve, & water level probe.

Take a pic of the wiring as it connects to the PID unit - the temperature sensor (probably thermocouple) wiring is polarity sensitive as is the ouutput wiring from the PID to the SSR.

Are you asking to open up the PID case and take a picture of the wiring for future re-wiring's sake? Or is there something we need to see inside there? A third option is that we need to see the wires and how they run from the back of the PID to the SSR? Here's one I took that shows the back of the PID, the power cord running out and down, the SSR connections up to the relay, and the brown thermocouple wire going around back.




But, I did disconnect the element again, turn on the PID and the machine, and the red SSR light just came on and stayed on.



Also, I did find these posts on the Bunn user Group. I just can't make sense of how he says to check the SSR for continuity. What I did was leave the bottom two connected (these are the two that run into the PID) and disconnected the top two (which run power). When I put my multimeter probes in those cavities, nothing happened. Reading on multimeter didn't change in any way. So, I think I'm doing something wrong there. He says to connect power to the input terminals...does that mean check for continuity with the PID and SSR on? Didn't make much sense to me. Perhaps, however, the test you recommended shows continuity.

--- In BUG-is-Bunn@yahoogroups.com, "Tex" <Texas_Coffee@...> wrote:

Mrs T woke me this morning, saying the ES-1A was popping and hissing. I removed the top and the pop-off valve was spewing - the machine was getting too hot. A quick look at the PID showed a 266F reading; the pop-off releases pressure at 14F past the setpoint.

FYI: I eschew the use of hi-limit tstats, relying instead on the PID setpoint, Alarm function, and the pop-off valve to control temps. I just don't trust bi-metallic tstats for this function - I'd opt for a thermal fuse before I'd use one.

Two things:
1) This was a SSR problem - continuity across the output terminals; why do they always seem to fail in the closed state?
2) The PID Alarm was set too high. At 280F it was past the point where the pop-off releases pressure.

I replaced the brew SSR and reset the Alarm to 260F, and everything is back to normal.

Tex


Re: When PID installs go bad.

I should've mentioned, to test most SSR's, connect power to the input terminals: DC models are polarity sensitive, AC models aren't. I do have some SSR's that must have current running through the output before they'll work - most SSR's don't have this.

Test results: No power & continuity = FAIL, Power and no continuity = FAIL.