Measuring and determining propane heat input (with PICS)

[DRbyrd]

The context of this is running propane with a CM/HM reflux rig.

It was a guessing game with me, knowing exactly what my heat input was. Some will say, "just watch the drip" but in an effort to save propane I like to only apply what heat is needed, have repeatable and predictable results and not waist gas by poring on the heat to just knock it down with increased water flow to the reflux coil.

I use to mark my pressure reg but as the tank pressure decreased that was not accurate.

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I had Idea or theory .... in most cases the temp of the burner is in direct proportion to the flame/BTU output of the fire? So, monitoring the the burner temp will indicate my heat input to the boiler.

The only inexpensive digital thermometer's that I have found that produce accurate, repeatable performance are the Chinese yellow two channel K-type thermometers designed primarily for HVAC servicing. You can have them at your door via Ebay or Amazon for less than $20 US. Just search "K-type digital thermometer"

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The thermometer's come with two inexpensive probes with 36" of fiberglass insulation. If you want to measure anything else, wort,mash, column air boiler temp , spend another $5-7 and get the K-type stales steel probe.

Here's the cheap one

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I put a little foil around the heat shrink tubing at the end of the probe and used JB weld to attach the probe to the base of the burner with the tip of the probe in contact with the burner. According to JB, the material does not produce toxic fumes when heated and it good to around 500 deg.

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I have found this to work great ! I now know my best heat setting for running as efficient as possible and for repeatable and predictable runs for like washes and volume. BTW is about 400deg for a 5 gal 8% ABV charged 15 gal SST keg boiler.

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I've found one exception. While in preheat mode when you have your burner in jet mode your burner will give you a false reading. With the point of the flame high several inches above the burner and the flame sucking in oxygen to feed the fire, you burners temp will actualy drop, giving you a false reading. That does not seem to be a problem since the preheat temp is not important and most don't run it that hard in fear of scorching the wash.