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In this Discussion
After the old forum software breaking in a way that we were unable to fix, we've migrated the site to a new platform.
Some elements aren't working as we'd hoped - some avatars didn't survive the transition, and we're still having issues with attachments that weren't added as inline images, but we're hoping to have that all sorted out soon.
Some elements aren't working as we'd hoped - some avatars didn't survive the transition, and we're still having issues with attachments that weren't added as inline images, but we're hoping to have that all sorted out soon.
Expobar Office Control Element Repair
NOTE: THE FOLLOWING IS A DESCRIPTION OF HOW I FIXED MY BOILER ELEMENT. IF YOU DIE TRYING TO FIX YOURS, IT IS NOT MY FAULT. PLAYING WITH 240V IS DANGEROUS AND CAN KILL YOU.
So the other day, I decided to descale my Expobar Office Control. I'd gotten it second hand and it was "5-6 years old" and "descaled regularly". The first time I turned it on, out went the power. The OPV was so shot that it needed replacing. I got a new OPV, new drip tray (old one was cracked and I was on my way).
Once I pulled it apart, and found the datestamp on the pump being from last century, I decided to not trust anything, and after a month or two, to descale properly (probably should have decided that when I saw chunks coming out the steam wand, but I digress).
I decided to descale manually, and just unscrewed the water probe, filled with descaling solution, drained, flushed, and put back together.
Once I plugged it in, all was well for a few seconds, then *bzzzzzzzzt* no more power. The safety switch had tripped.
What had gone wrong??? - I started troubleshooting, and quickly found that the element terminals to ground were reading anywhere between 100k Ohm and 8M Ohm (which, at 240V would mean as much as 2.4mA leaking to earth if the multimeter was accurate. At higher AC voltages, things can be a bit different though, hence AM's suggestion in other threads of not always trusting them. For reference, most RCD's won't trip until about 5mA, so it's entirely possible that even with this fault, it would still work, but wouldn't necessarily be safe.
A lot of people think that an RCD will save them in all cases. I like to think of them as an "Electron counter". It counts the electrons going in active, and back out neutral. If it doesn't make it back (ie it flowed to earth) it trips. This means if you grab an active and neutral wire, and are not connected to ground, you die. That simple. Never rely on an RCD to save your life. Assume it isn't there, but be thankful when it is!
In short, just by tipping it on the side and up side down, I believe the water had moved around in the contacts that had built up from a previous OPV failure that had caused water to spray all inside the machine.
Once I got the boiler out (It was a lot harder to find a 1 1/2" Socket than I thought it would be), further testing indicated that there must be moisture in the contact points. I pulled the ceramic terminal blocks off, and cleaned out the messy gunk that was in there, then baked in a hot (215 degrees C) oven for about 4 hours. I then cleaned it again, baked another hour, and left to cool. Note: AM has suggested baking at a low (sub 100 degree) temperature for a few hours before cranking the heat, because things can explode.
After this, the element was reading 46 Ohms across the terminals (which is what it should read) and open circuit from the element terminals to the base of the element screw.
I now had an issue of terminal blocks that weren't safe, or waterproof.
I went hunting for a ceramic sealant, and was recommended this one: http://www.sauereisen.com/pdf/HIGHTEMP.pdf combined with Glyptal 1201 Red Enamel for sealing. I couldn't find either despite trying many places and phoning around.
I ended up going to a generic hardware store, getting some PC Fahrenheit Epoxy (Rated to 260 degrees C), using that to fill the terminal blocks, then coating in Selleys Appliance Enamel (Rated to 200 degrees C). I'm hoping these will handle the heat, but will keep an eye on if they are going brittle over time.
Once the machine was back together, filled the boiler manually, turned on, and presto, no more short.
Total cost: $42 for tools + $32 for epoxy and enamel = $74.
I didn't really save much money, because a new element is only just under $100, but I had fun, and learned a lot in the process. If one already had the tools and epoxy (which is possible) it would be a cheap repair.
So the other day, I decided to descale my Expobar Office Control. I'd gotten it second hand and it was "5-6 years old" and "descaled regularly". The first time I turned it on, out went the power. The OPV was so shot that it needed replacing. I got a new OPV, new drip tray (old one was cracked and I was on my way).
Once I pulled it apart, and found the datestamp on the pump being from last century, I decided to not trust anything, and after a month or two, to descale properly (probably should have decided that when I saw chunks coming out the steam wand, but I digress).
I decided to descale manually, and just unscrewed the water probe, filled with descaling solution, drained, flushed, and put back together.
Once I plugged it in, all was well for a few seconds, then *bzzzzzzzzt* no more power. The safety switch had tripped.
What had gone wrong??? - I started troubleshooting, and quickly found that the element terminals to ground were reading anywhere between 100k Ohm and 8M Ohm (which, at 240V would mean as much as 2.4mA leaking to earth if the multimeter was accurate. At higher AC voltages, things can be a bit different though, hence AM's suggestion in other threads of not always trusting them. For reference, most RCD's won't trip until about 5mA, so it's entirely possible that even with this fault, it would still work, but wouldn't necessarily be safe.
A lot of people think that an RCD will save them in all cases. I like to think of them as an "Electron counter". It counts the electrons going in active, and back out neutral. If it doesn't make it back (ie it flowed to earth) it trips. This means if you grab an active and neutral wire, and are not connected to ground, you die. That simple. Never rely on an RCD to save your life. Assume it isn't there, but be thankful when it is!
In short, just by tipping it on the side and up side down, I believe the water had moved around in the contacts that had built up from a previous OPV failure that had caused water to spray all inside the machine.
Once I got the boiler out (It was a lot harder to find a 1 1/2" Socket than I thought it would be), further testing indicated that there must be moisture in the contact points. I pulled the ceramic terminal blocks off, and cleaned out the messy gunk that was in there, then baked in a hot (215 degrees C) oven for about 4 hours. I then cleaned it again, baked another hour, and left to cool. Note: AM has suggested baking at a low (sub 100 degree) temperature for a few hours before cranking the heat, because things can explode.
After this, the element was reading 46 Ohms across the terminals (which is what it should read) and open circuit from the element terminals to the base of the element screw.
I now had an issue of terminal blocks that weren't safe, or waterproof.
I went hunting for a ceramic sealant, and was recommended this one: http://www.sauereisen.com/pdf/HIGHTEMP.pdf combined with Glyptal 1201 Red Enamel for sealing. I couldn't find either despite trying many places and phoning around.
I ended up going to a generic hardware store, getting some PC Fahrenheit Epoxy (Rated to 260 degrees C), using that to fill the terminal blocks, then coating in Selleys Appliance Enamel (Rated to 200 degrees C). I'm hoping these will handle the heat, but will keep an eye on if they are going brittle over time.
Once the machine was back together, filled the boiler manually, turned on, and presto, no more short.
Total cost: $42 for tools + $32 for epoxy and enamel = $74.
I didn't really save much money, because a new element is only just under $100, but I had fun, and learned a lot in the process. If one already had the tools and epoxy (which is possible) it would be a cheap repair.
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