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Ebay Urns, quality issues, how well they work and mods

Post #1 made 13 years ago
by Skinah
I just purchased a 30L brand new chinese made URN from ebay for $125 delivered to my door as I am looking to hear if anyone else has modified their urns with the ideas that I am considering.

First of all I have disabled the boil dry thermostat and left the temperature dial control working, and done 1 brew and found the urn to work great with 1 draw back. The boil is very vigourous with wort jumping up 7-8cm high so I have to keep manually turning the urn down and back up again as the urn has a temperature dial which if I set this to 100 then it boils too much till the control kicks in and turns it fully off until the wort cools back down a few degrees and the wort is no longer at a rolling boil. I can set the control to 110 and it never hits the cut off temperature and keeps boiling with the wort jumping up and almost out of the urn with 23L of water.

Now to the mod...
The urn has two elements wired in parallel, one marked 1000watt and the other 1800watt. I am thinking of wiring it so that 1 of the elements is always on (controlled by temp termostat dial) and the second one is connected to a switch or possibly to the boil dry thermostat to make it automatic.

I am hoping this will allow both elements to be in use to quickly boil the water and then once boiling I can disable one of the two so the boil is not so extreme. I am hoping to lose less water from evaperation and be able to fit more wort into this smaller 30L urn by doing this.

Anyone done this to save me the time trying it out myself? The Urn works great as I can dial in 72 degrees walk away and come back and be sure the water is at the right temp, it is just the boiling part that needs some fixing.
Last edited by Skinah on 04 Sep 2010, 10:58, edited 1 time in total.

Post #2 made 13 years ago
by widdley
Hey Skinah good to here from you!,
You'll find going AG (BIAB style) is the best decision you've ever made :D

Those cheap ebay urns appear do have a mixed history... some people have been really lucky with them while others have blown them up after a few brews :( . Hopefully yours will go forever, if not you can buy better immersion elements quite cheaply and just retrofit the unit...

A word of warning though, be careful doing the sort of electrical modification you are proposing unless you absolutely know what you are doing :!:. Sorry for the lecture especially if you happen to be an electrical engineer or something :roll:, but too many of these stories end badly so I figured its better to warn you now so you have a chance to become a great brewer and then an opportunity to send me some beers to try :D

Firstly, boil dry protection is a safety feature so if you remove it, make sure you add an alternative way to avoid a potential boil dry event - which will totally stuff the urn and potentially cause a fire!.

Secondly a lot of cheap urn elements can't handle running flat out for extended periods. The boil dry protection is actually an over-heat protection and is especially important if the elements are the conceiled type. If the element overheats it will burn out and potentially start a fire.

Thirdly the total power of the 2 elements is 2800 watts meaning that if they are both running flat out you will be drawing about 12 amps of current. You need to make sure that you plug it into a 15 amp rated power point as most standard house circuits are only 10 amp (event though the fuse will say 15). 15 amp powerpoints have a hole for a bigger earth pin. Unfortunately cheap Chinese plugs probably dont have the larger pin that prevents people from sticking them into standard powerpoints. If you draw too much power from the circuit for too long then the wires in you walls will heat up and once again may potentially start a fire.

I am interested to know how sluggish your boil was prior to modifying the urn? I brew outside and still get a pretty good boil on a 7 degree day with only a 2400 watt conceiled element. The trick is to insulate the urn with anything that won't melt - I use old wool carpet. You can also buy cheap hand held, or over the side imersion elements if you need to boost the boil - just plug them into a different power circuit.

Hope this is useful too you :D When it comes to brewing I'm pretty new and still making lots of mistakes, but I do some stuff about electrickery...

Dave

Post #3 made 13 years ago
by Skinah
Thanks Widdley,

I'm looking forward to doing my first AG soon as my first brew was using extract with crystal grain to test the new gear out.

I do know a bit about 'electrickery', spent many years repairing electronics...

I have only used the Urn once and that was after disabling the boil dry, so I will try it with it re-enabled to see how it goes.

Your right this Urn is a bit of a worry as the elements are rated at 220V (probably the reason they have a short life for some people) so they will be even higher than 2800 watts on our 230V power here. I am tempted to completely disable the 1000 watt element and just let the 1800 watt element (probably closer to 1950 watts with the voltage above the rating) to do all the work. Since I will only brew inside and it is a 30L (24L of water) urn hopefully that is enough to keep a rolling boil, if not I can mod it back or install a better element as you suggested although it may be better to just buy a better Urn.

I have old wiring and old ceramic + wire fuses in my house, so your right it is not the best thing to be sticking into a 10amp rated power point. Another reason to perform a mod on this unit. Surprised someone has put a C-tick sticker on this with no fuse, a 10amp rated cable, a lightly spot welded earth tab that could fall off and spade terminals on all wires which can fall off and touch the metal sides since the heat shrink job is not the best.

I am also interested to know if the teflon tape material on the tap thread and also the gasket that seals the element is food grade. Guessing not. Using the Urn to boil water for the first time brought a very strong sulfuric acid smell which is probably used as flux in soldering (hopefully lead free) up an area where they burnt through the thin metal sides.

It is a very cheaply made Urn and hopefully it lasts long enough to get a large number of brews done.

Post #4 made 13 years ago
by Skinah
I re-enabled the boil dry and disabled the 1000 watt element so only a single 1800 watt element is now opperating as standard. I did a test run today with 24L of 10 degree C water in a room around 17 degrees.

Took 60 minutes to reach 70 degrees C with the lid on. I watched and it was around 1 degree per minute and this was a bare URN with no insulation.

After 90 minutes the water was at a rolling boil with the lid on. After another minute the boil was touching the lid, jumping up 4cm so I removed the lid to stop it going everywhere, this reduced it back to only just boiling with only the surface area directly above the element rolling. By placing the lid back on and giving a small gap to let out some steam I can easily keep this much water at a good boil.

Result is the URN is now safe/r to use on a 10amp circuit and can still produce just enough heat with the control turned up to 110 and the lid off. With the URN as standard the boil with the lid off was way too much and would have resulted in wort being thrown up and out of the URN. So this has improved it to what I was trying to achieve and it has boil dry protection.

I also measured the heat control thermostat and it waits for the water to drop 5 degrees below the set point before it turns the element back on. So the control must be set to 105 or more for it to stay boiling non stop.

I would not recommend these URN's for the reasons in my last post, nor would I recommend anyone to do what I have done unless it is performed by someone who can do it safely.

This should do the job for a while as I try out BIAB and AG brewing.

Post #5 made 13 years ago
by Skinah
To identify if an URN you have purchased or about to purchase is the same as this chinese one I have, there is a white paper sticker on the side with the power requirements. It specifies that it is 220V and needs 13.6 A (amps) on this sticker and "type WS38" which must be the model.

Post #6 made 13 years ago
by dick
G'day Skinah

I have exactly the same 30L urn with WS38 written on the white sticker. I got this urn as a cheap way to get into all grain brewing. I gotta say that BIAB using an electric urn and no-chill in a cube has to be the easiest way of making beer with grain and I'm loving it. I have done 15 batches with this now.

I know what you mean about the boil, it's like it's about to erupt. The boil is far too vigorous. You can set the temperature but can't regulate the amount of power going to the urn and 2800W is too much power for a rolling boil.

I asked the sparkies at work about it and they gave me a device that allows me to control the power going to the urn. I plug the urn into this device and this device plugs into the powerpoint. This device is a phase-fired controller and I guess you already understand how these things work. Anyway, now I just turn the dial to maintain the boil just right. Too easy.

Cheers
Dick

Post #7 made 13 years ago
by Skinah
Using a device like that is a good idea as you would lower the current draw and also the voltage going to the element. Good idea and thanks for the suggestion which this is a much better way than modifying the URN as you would get excellent control over the heat.

Your device could be...

rheostat = wastes the extra power as heat and would not lower the current draw from the power point.

Variac = A good way to do it but they are heavier and larger than Triacs as they are variable transformers. These will not create hums, buzzes or electrical interferrence. Easy to find these ready made.

PWM Triac/s.c.r controller = Would be small, light weight and a good way to go. You may hear a 50hz hum/buzz/interf. with these.

Kits can be purchased from Altronics and Jaycar to DIY a triac controller which should work with a heating element.
http://www.altronics.com.au/index.asp?a ... m&id=K6035

I can not find any premade ones for sale anywhere on the internet with Australian plugs. If anyone knows where to buy one then please post a link.
Last edited by Skinah on 05 Sep 2010, 22:44, edited 1 time in total.

Post #8 made 13 years ago
by dick
Hey Skinah,

Yes this is a PWM type device but there is some subtle difference that is lost on my understanding of such things. I have no idea where you could buy one. I was lucky enough to come across something that my workplace had no use for anymore. It's great and makes the boil so easy. Sorry I can't be more helpful but if you were able to work out how to make one of these or where to get one, I think there would be plenty of people who would be interested.

Cheers
Dick

Post #9 made 13 years ago
by widdley
Skinah wrote:Result is the URN is now safe to use on a 10amp circuit and can still produce just enough heat with the control turned up to 110 and the lid off.
Right then... No more excuses, go and make beer :D
Last edited by widdley on 05 Sep 2010, 18:52, edited 10 times in total.
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