# Water line thermometer



## Bugzapper (Sep 22, 2009)

I'm looking for several thermometers to keep tabs on my water heating system at various stages. (Incoming boiler temp, post exchanger DHW temp, tempering tank, post water heater and finally post mixing valve.  I want to put these on my 3/4" lines and would prefer to just clamp them to the outside of the lines and not cut anything.  They needn't be super accutate, just to use as a reference.  dDigital or dial, not important.
I have searched the forum and can't find any reference and my net search seems to be enless without finding the specific item I am looking for.  
Any suggestions?  I don't think this is really necessary, but I am really curious about what is going on with my system.

JB


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## Nofossil (Sep 22, 2009)

This comes up a lot - perhaps our mods can find some posts and add them to the appropriate sticky.

Three choices I can think of:

1) Use a handheld IR thermometer with masking tape targets

2) Use wireless barbecue thermometers

3) Use adhesive backed liquid crystal thermometer strips


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## jebatty (Sep 22, 2009)

I use the "milk frothing" (use that search term) thermometers which I got on ebay. They are similar to a meat probe thermometer, but have a narrower temp range suited to boiler operation and a larger dial. I use cable ties to get pretty good contact with the pipe, wrap with fiberglass insulation, and secure with electrical tape. If you get several, let them all stabilize in the same location, and if any read much different you can rotate the fitting on the back so that they all read the same.


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## Bugzapper (Sep 23, 2009)

Good idea.  Thanks.

JB


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## pybyr (Sep 23, 2009)

Look at the Azel digital thermometer- has two sensors and readouts; compact, well made.


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## Gooserider (Sep 23, 2009)

Nice idea for those milk thermometers, looks like they would be an ideal range for doing analog readouts.  The only question I would have is whether or not you could bend the stems on them?  It would seem like a nice thing to me if it were possible to bend the stem at a right angle (or other angle) so that you could have the stem fastened along the pipe with the dial facing out for easy reading...

Will try to see if I can find some of the other threads which give options...  Of course there is also the obvious "high end" approach - get a NoFo controller w/ lots of extra analog inputs (or maybe the One Wire option he's working on) and use it to do a centralized data collection - even if you don't use it to control the system...

Gooserider


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## jebatty (Sep 23, 2009)

In my experience a very gentle, minimal bend is OK, like that required on copper pipe with the probe on the straight length of pipe, then extending over a 90* fitting, with the dial in open air. I also have laid the probe along the length of a copper pipe at a slight angle so that the dial clears the pipe. This one has worked too, but have to be careful. I think there might be a wire that twists inside the probe to turn the dial, and if it gets too much friction from rubbing inside the probe, it won't turn the dial or it will stick before making a sudden jump in reading.


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## Bricks (Sep 23, 2009)

To accuratley adjust these type of thermometers. Take ice cubes in a bowl add water, let sit for a few minutes. Put thermometer in water, should read 32 degrees adjust as needed.


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## flyingcow (Sep 23, 2009)

Bricks said:
			
		

> To accuratley adjust these type of thermometers. Take ice cubes in a bowl add water, let sit for a few minutes. Put thermometer in water, should read 32 degrees adjust as needed.



You beat me to it. I use these in measuring temps of milk in the tanks. Anytime I've dropped and bent them I could not get them to recalibrate, but I have to have mine sent to the lab to get a "official" recalibration. If bent they recommend discarding. But that's regs dept for you. At the lab, they do the same thing, put it in ice water. But they're the pro's.


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## DaveBP (Sep 23, 2009)

Be interesting to check your thermometer at the other end of the scale after calibrating it to freezing. Use boiling water and the correction table on this page to allow for altitude:

http://en.wikipedia.org/wiki/High_altitude_cooking

If there is a substantial misreading at high temps I would opt to calibrate it to the temperature closer to what you will be using it for.


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## in hot water (Sep 23, 2009)

these snap on thermometers were built for balancing radiant loops.  They fit 1/2" pex but they do "stretch" enough to fit 3/4' copper tube.  Smear a bit of heat transfer paste and snap them on.  This one happens to read in C.  I have some that read in F also if you want to try some let me know.

 hr


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## Bugzapper (Sep 23, 2009)

HR:
Those look like they should work.  Not exactly what I was looking for, but workable.  How much are they?  I would want a half dozen or so.  PM me with your contact info.

JB


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## willworkforwood (Nov 10, 2009)

I picked up 5 of the "frothing" thermometers mentioned earlier in this thread on ebay last week; gently bent the stems as Jim described, synched them up in some ice water, and attached them with asj tape covered with pipe insulation.  I've been wanting a way to monitor my system better, and along with a probe flue therm, these go a long way toward providing helpful info.   Right off the bat I found a problem with a zone valve to the Superstor - still not fully resolved but, at least I'm aware now and can get it figured out.  I would recommend adding them in if you don't have any - the more info you have about your system, the better off you will be.  I can send the ebay item that I used if anyone wants it, but there are others that look ok also.   I'm going to pick up another bunch, and then send my wife down to the basement to enter the numbers into a spreadsheet.  If she can get the data in fast enough, I'll have a real-time system that even nofossil will be envious of  :lol:


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## maplewood (Nov 10, 2009)

I was thinking of monitoring temps at various places on my new boiler, too, and was planning on a few mounted thermometers.
But I found a laser thermometer at the local Canadian Tire (auto and home supply store) for 75% off, and now have a neat toy.
I'll put a mark on the pipes, tank, chimney, etc. where I want to monitor temps, and aim the laser there.
And I've got my dog running circles around the wreck room! (I've got 5 kids - it became a "wreck" room years ago....)
Happy burning.


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## sdrobertson (Nov 10, 2009)

I have purchased 6 of these over the last year and a half as I keep finding other places to check temps.  They work really well but the leads are only about 2 ft long.  Work well for the price.  http://cgi.ebay.com/Digital-Thermal..._trkparmsZalgo=NGRI&its=I&itu=UA&otn=10&ps=63


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## heaterman (Nov 10, 2009)

Viega makes a 2-1/2" diameter gauge that reads from 32-250*F. It comes with a surface mounted "well" that can be soldered directly to copper tube of about any size or secured via a spring the wraps around the back of the tubing. It also includes a small tube of heat transfer paste if you don't choose to solder it on and they cost about $15 IIRC.
I've found them to be decent accuracy wise. Not as good as direct immersion but very close.


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## flyingcow (Nov 10, 2009)

When my installer said "you can't have enough thermometers in a system" when he was installing mine, i told him to do it like it was his own. I've got a lot of well type thermometers, love 'm. Not a one wasted! Every junction, etc, is set up right. Just now I've got to hook up a system to look at it from my kitchen. Not a problem since I'm gleaning info from this thread/forum.


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## WES999 (Nov 11, 2009)

Here is a thermometer setup I am working on, it is a food thermometer that is mounted in a compression fitting in a piece of copper pipe.  I will probably mount it in a sharkbite tee when it is all finished. The food thermometers are relatively inexpensive and fairly accurate.


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