Urn Overheating Problem

[pbrosnan]

Hi Urn users and others,

I have started doing 90 minute boils for a while just to see what difference if any it makes to the finished product. Yesterday I had a problem with the 30L urn I use as a kettle shutting down after about 75 mins. I had this before and it's due to a build up of residue on the element. Previously it only happened when I didn't clean the element after a number of brews. I suspect it's caused by the length of the boil. Anyone else seen this or have any suggestions regarding prevention?

 

[lou]

I had a similar problem with my boiler which had a kettle element bolted in the side. Kept shutting down - unfortunately wasn't anywhere near the end of the boil -

Basically the element has it's own thermostat - of course there's the controlable thermostat but there is another one in the back of the element itself which stops the element over heating - the main purpose of these is too stop the element burning out if you turn it on without any water in the urn. I basically ripped the internal thermostat out - no problems after that !! The slightly higher operating temp doesn't seem to affect the element or i haven't found it a problem so far after about 10 goes

Of course you have to make sure you don't turn it on dry - but not likely if you are paying any attn to what you are doing while you brew.

I did the same thing with the kettle elements in the my new bigger boiler.

You would have to take out the element and look where the wires connect to the element - it's usually not that hard to work out hoow to disable it/ rip it out or just bypass the circuit if you are at all familiar with wiring electricity.

there are 2 or threee diff types of internal element thermostat - each one requires a different solution and of course you need to be able to access the back of the element.

lou

 

[pb unleaded]

My 40lt urn was switching on and off during boil even though it was set to max (110deg). I have since installed a switch to overide the thermostat. Did your urn shut down completly? If so then the problem is elswhere.
arthur

 

[pbrosnan]

Hi Fellows,

Thanks for the responses. I've had the bottom of the urn before so I'll have a look at bypassing the element thermo. The urn didn't completely shutdown and I'd say the the diagnosis you've given will be the cause of the problem.

 

[pbrosnan]

My 40lt urn was switching on and off during boil even though it was set to max (110deg). I have since installed a switch to overide the thermostat. Did your urn shut down completly? If so then the problem is elswhere.
arthur

Hi there,

I had a look at the bottom of the urn and it's not obvious where the boil dry thermo is. I've got a Zip, anyone else got one of these. And could someone post a pic shwing their mods, may not be the same as mine but it might help.

 

[chimera]

Currently in the process of rebuilding my urn so i have it handy..

If its anything like my Jomack (and they are all probably much the same) the element itself has an inbuilt thermal cutout as part of the boil dry protection.

Check the pic below (pardon the mobile phone camera), the top tab is ground, large two horizontal are the heating element, the bottom two vertical are a thermal cutout which is wired in series with the element.



The thermal cutout will be a small two pin plug that may look similar to this:

T'STAT,N/C,OPEN @110+/-3C

My suggestion is that if you install a bypass switch, you will likely want to bypass both the thermostat/simmerstat and the thermal cutout.

Hope that helps.

 

[pbrosnan]

Currently in the process of rebuilding my urn so i have it handy..

If its anything like my Jomack (and they are all probably much the same) the element itself has an inbuilt thermal cutout as part of the boil dry protection.

Check the pic below (pardon the mobile phone camera), the top tab is ground, large two horizontal are the heating element, the bottom two vertical are a thermal cutout which is wired in series with the element.

View attachment 8875

The thermal cutout will be a small two pin plug that may look similar to this:

T'STAT,N/C,OPEN @110+/-3C

My suggestion is that if you install a bypass switch, you will likely want to bypass both the thermostat/simmerstat and the thermal cutout.

Hope that helps.

Hi there,

That's a great help, thanks. On mine there are two wires that fit onto the back of this thermo. I'm assuming that these need to be wired together, either directly or over a switch?

 

[ausdb]

Hi there,

That's a great help, thanks. On mine there are two wires that fit onto the back of this thermo. I'm assuming that these need to be wired together, either directly or over a switch?

Patrick, post a pic of your urn and I will try and help

 

[pbrosnan]

Hi there,

That's a great help, thanks. On mine there are two wires that fit onto the back of this thermo. I'm assuming that these need to be wired together, either directly or over a switch?

Patrick, post a pic of your urn and I will try and help

Hi Darren,

Thanks, here's a couple o' pics including one showing the wiring diagram, let me know if you'd like more details and I'll see if I can get in closer. Got anything on the go brewise at the moment?

 

[ausdb]

Thanks, here's a couple o' pics including one showing the wiring diagram, let me know if you'd like more details and I'll see if I can get in closer. Got anything on the go brewise at the moment?

Aah much better, The overload as stated is the thing with the flat disc held down by the tab with the white and red wires connected to it. To bypass you just need to join the white and red wires together, or attach a switch rated for at least 10A in parallel across it (provided the element is only 2400W). If the urn has a 15A plug then it probably has a 3000W element which will draw about 13A (@230v) so would need a higher rated switch. Switch choice is up to you but keep in mind that its likely to get wet as well when choosing, if adding any wires make sure it is temp rated the same as the wires in the urn as well.

The thermostat on your urn is a simmerstat type and I guess it doesnt actually have temperatures on the dial, more than likely just numbers 1-10 or something? If it does then it probably has a full on position, does it feel like it clicks again when you turn it all the way around to full as well? That being the case you dont need to bypass the thermostat.

Brew wise has been very slow

 

[chimera]

Hey neat, they even gave you an urn wiring diagram.