I am building my control panel following Kals excellent instructions, but I did not notice that he recommended using a 16/14mm RTD on the BK and not the 1/4" ones. Is this a reason other then being a bigger thread/body and the 14mm comes with the waster and nut. I already ordered 3 1/4" and I could return one and get the 14mm. I was also thinking about welding the nut on to the outside of the BK(keggle for me), should I get the 4" so it runs deeper in the keg. My keggle has a spare 1/2 full coupler welder on already, I could get a 1/2 to 1/4 thing and put the 1/4" rtd in there, 2" will not stick very far into the keg though, does it have to?
Joined: 12 Dec 2010 Posts: 10341 Location: Ottawa, Canada
Drinking: German Lager, Electric Hop Candy Jr, London Pride, Weizen, Citra DIPA, Dubbel, Russian Imperial Stout, Black Butte Porter
Working on: Kolsch
Link Posted: Mon Dec 27, 2010 2:41 pm Post subject:
The size of the temp probe in the BK doesn't matter but it needs to be straight (METRIC) thread, not NPT tapered pipe thread.
NPT (tapered) probe:
METRIC (straight) probe:
The temp probes in the the MLT and HLT are NPT threaded which is tapered (gets wider the farther you go in). It's meant to screw into a pipe of some sort. The part you screw into is also tapered (gets smaller the farther you go in).
Because of NPT tapering you can't use a nut. Since you don't know where it'll stop turning. The BK probe is metric straight thread. Just like a 'regular' bolt. You can put a nut on it and fasten it at any point.
You can most certainly weld on a fitting if you want but you have to be careful doing it. There's no benefit to welded on a setup like mine so I didn't bother as the chance of punching a hole accidentically through the pot when welding is high if you're not good at it. I wanted to weld on fittings for the heating elements before I designed my way of doing it. All of the welders I talked to looked really uneasy when I showed them the pots. Most said that they "would try" but couldn't guarantee that they wouldn't punch holes in the pot given the narrow wall (relatively speaking to what most people weld with).
There's no need or benefit (or harm for that matter) with using a 4" probe in the BK. The 2" sits enough in the liquid. I use 2" as it's out of the way more during cleaning. It's also $1-2 cheaper.
Joined: 23 Dec 2010 Posts: 570 Location: Pottstown, PA
Link Posted: Mon Dec 27, 2010 3:46 pm Post subject:
Ahh, did not think about the taper of the threads. Thanks, it does make sense. I am using keggles, they are at the welders now. I had them add a half coupler for a thermo/site glass, I could just swap the thermo with the RTD (1/2" to 1/4" thingy) and probably be ok, I just do not think much of the probe will be in keggle, need to measure the T and the coupler once I get them back. I sortof wanted to keep a thermo, I paid for it, might as well use it, also I think it looks cool. I wonder if I could remove the site glass and just put the RTD in there, it would be in the T, not in the keggle though.
I also had them weld on two extra full couplers so if I ever wanted to install a built in IC(the welder was doing this all for free, so I took advantage of it), one around half way up and one at the bottom. I could just install it there, but there goes my built in IC. The plan was to use the built in IC and whirl pool the wort through the herms coil and get a double cooling action. Maybe I will return the RTD and just get the metric and install it like you suggested. So many options.
BTW, I cant thank you enough for your detailed instructions. I wanted to go electric, but it look way to complicated until I found your site through HBT.
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