What kind of thermometer to plumb in for mixing hot/cold water

[barleyfreak]

I mix cold water with hot from two on-demand heaters for my strike water while doughing in. Have been using one of these but it is pretty slow and I'm trying to find a larger, faster dial to have our plumber install. What are others using? What are the best thermometers for reading water temp in copper? Fastest, best range for brewing needs, etc.?

[TGTimm]

Skip the thermowell. There is really no purpose for it pre-boil. This will greatly reduce the response time of your thermometer. I just put an FPT fitting after the mixer to use for the thermometer. Also, remember that you'll need to be calibrating the thermo regularly, so make it easy to get to.

[barleyfreak]

So you have an FPT coming out of the copper and have the thermometer screwing straight into the water flow? Our water is mixing via the copper plumbing. What kind of thermometer do you use?

[barleyfreak]

So something like this in the mixed water line with this screwed in?

[TGTimm]

Yep, that's basically it. We use all soldered copper, but the end result is the same. To facilitate calibration, it would make very good sense to use a 1/2" MPT-1 1/2" TC fitting to that T, then mount the thermo in a 1/2" FPT-1 1/2" TC flange. You'll need a longer stem on the thermo, but it's much quicker to change out.

Now get a good NIST certified glass (MIG) thermometer to use when calibrating your dial thermometers. We calibrate the mash tun, sparge and castback (cold-side wort) thermos every day we brew. They need it.

[barleyfreak]

OK. Making sense. But what is the flange? If I connect this (1/2" MPT-1 1/2" TC fitting) to the T, then wouldn't I just connect a TC sanitary Thermo to it, like this (I'd probably get one from Reotemp rather than this brewmagic one though)?

[TGTimm]

Sure. But this is all hot-side, so a sanitary thermo is somewhat overkill ($65 vs $35 (and expect to have some breakage of thermos)). That thermo would be ideal for cool wort side of the HX, 'though. The only purpose of the TC fittings on the mash-in water is to make it easy to remove and calibrate the thermo.

[barleyfreak]

Got it. On the right track now. Thanks for the advice.

[barleyfreak]

Thanks for the advice Timm. Installed a 4" dial Reotemp thermo directly in the water stream via a TC fitting. Easy to remove/calibrate. Easy to read (my eyes! my eyes!). Very fast response. As a temperature obsessed brewer (aren't we all?), I'm very much liking my easy to see, accurate water temps.

cheers,

[TGTimm]

As a temperature- (and labor-)obsessed brewerywright, I've been trying to source a reliable, accurate, and precise electronic thermometer that would not need to be calibrated (well, only once), for our mash-in water and our knockout wort (post HX). Amazingly, such a thing does not seem to exist! The best solution I've come up with is a Fuji PZ thermocontroller with a PRT based RTD probe. Unforutnately, the cost for one of these runs about $600+ each. However, since these controllers have an analog output, it should be fairly east to use the knock-out thermo to control the speed of our knock-out pump via the VFD that drives it, thus controlling the knock-out temp without the need to have a brewer constantly monitoring it. With a little electronics and a stepper-motor driven proportioning valve (another $1,000+), it should be possible to control the mash-in water temp, too.

Maybe I'll get around to it this Summer....

[scotts]

TGTimm - I was looking for something else when I stumbled across this item and remembered this thread. I don't know if this could be hooked up to your pump's VFD but another solution would be a temperature controller with linear output to a proportional valve that controls the flow of the cold side of the HX. Take a look at this selection. I have no idea on pricing, but Burkert equipment is usually pretty reasonable.

http://www.burkert.com/en/products/control-valves-and-controllers/control-electronics-for-solenoid-control-valves

The product description for the first one reads:

The digital control electronics, Type 8605, serves to operate proportional solenoid control valves in the power range from 40 - 2000 mA. The electronics converts an external standard signal into a pulse-width modulated (PWM) signal with which the opening of the proportional valve and hence a fluidic output parameter (e.g. flow rate) can be infinitely varied. An internal current control with the duty factor of the PWM signal as manipulated variable ensures that every value of the input signal, irrespective of the thermal condition of the coil, is unambiguously assigned a given value of the effective coil current. A display and operating keys allow the electronics to be easily adapted to a particular proportional valve and to the concrete conditions of an application.

http://www.burkert.com/en/products/control-valves-and-controllers/control-electronics-for-solenoid-control-valves/178354

[TGTimm]

scotts--thanks for the heads-up to Burkert Valves. I'll be looking into these when we get our recent new equipment purchases paid off!