HEAT TRANSFER GREASE

Brad White

I have used it for years and it gets "thick" maybe but never hard, even after years at temperature. At worst, when withdrawing a thermometer it makes a "giant sucking sound" but without job loss.

Maybe I have a Laboratory Escapee jar? :)

J RACINE

HEAT TRANSFER GREASE FOR AQUASTAT WELLS. HOW IMPORTANT IS IT ? I HAVE RUN ACROSS A COUPLE OF INSTANCES WHERE THE AQUASTAT BULB WAS CEMENTED INSIDE THE WELL BECAUSE OF THE GREASE. AT 12:30AM IT MADE A 15 MINUTE JOB TURN INTO AN HOUR AND A HALF BECAUSE OF DRAINING SYSTEM(NO VALVES) AND REPLACING WELL THEN REFILLING AND PURGING. I DIDN'T KNOW IF SOMETHING WAS DONE WRONG? JUST A QUESTION. J

Brad White

Honeywell Tradeline Heat Conductive Compound

if used should never harden. It is essentially Vaseline with aluminum powder mixed in.

Are we talking the same application? The stuff is used in a thermo-well which is tapped into the piping. You should not need to drain the system unless you removing the well or using a direct-immersion instrument.

Sounds like you maybe had Expando and removed the well not the instrument. Turn the light bulb not the house

I personally insist on heat conductive paste for all well applications. Contact is key especially with 10k Ohm thermistors.

John Starcher_4

I have had....

...the same experience with "whatever was in the well" hardening, and making it a real beeyatch to remove the sensor bulb.

I don't know if it was the honeywell paste or not, but it was a real pain in the rear, and draining the system was not going to be an option. I got lucky, and the bulb finally came out, but not without causing me to have to replace the aquastat.

Darrell

I'm a serviceman...I hate it when the heat conductive compound is used...it does harden and make it darn near immpossible to get the aquastat out of the well. Besides, it gets all over everything and makes my potato chips taste funny!

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hr

I cut a tapered copper shim

out of a scrap piece of 3/8 or 1/2 copper tube. Tap it in along side the buld with a tab for easy removal. A much more "service-friendly" method for sensor installations.

There was a time you could buy those thin curved shims.

hot rod

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Unknown

After 47 years

in this industry and having worked for Honeywell for a few years the truth is it hardens most of the time.

The solution if you are going to use it is to mix it with some gas valve key grease. That will keep it soft.

Bruce Stevens

I rarely use it

however if you have to pull the well just take the pressure off the system, close any vents and pull the well and have the new one ready to install you will probably loose less than a cup of water. If you can close off upper zones as extra insurance.

Tom_80

Heat trasfer

I use never seize as a heat transfer substance and the bulb slides out nice

Bruce Stevens

Knowing you Brad

you probably pull and change grease anally oops I meant annually when changing the filters, cleaning magnets and replacing marble chips, now we get there for the first time in fifty years and guess what oops hard as Cape Cod Potato Chips.

Leo

I hate it

I have ruined a few aquastats and wells trying to remove what someone else cemented (use of heat grease) in. I once had a boss who forbid it's use.

Leo

Unknown

I`m with Bruce & Darrell,

I never use the stuff, if I wanted glue, I`d have ordered-it.

Dave

Bruce Stevens

Brad one other thought

if you are using thermometers then I could see a straight solid shank coming out, however think about a control bulb and the thin piece of tube it's attached with, add some of that grease let it get semi hard and it will take a semi trailer truck to pull it out passed the grease built up behind it, BAM next thing you know is the tube breaks off, recipe for disaster.

ScottMP

Brad

How many aquastats do you see from your desk ???



Scott

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hr

It's the Euro sized wells and bulbs

that throw a wrench in the works. Their dimensions are just enough off from the sizes we are used to. So it's hard to mix and match sensors and wells.


I installed a Viessmann boiler that had 3 probes in the same 1/2 well that we commonly put one in. Great idea really, if you have sensors that are about 3/16" in diameter

The switch to thermistors from cap tube controls further complicates the well to sensor fit.

Stem lube would probably work as a first coat, then the transfer grease. Stem lube is in most plumbers tool kits already. It stays soft and pliable for years.

hot rod

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Unknown

Do you really need the

stuff is the question? I was told that the reason you do not see it when the equipment is new is that it is not allowed as part of the testing process on new equipment by the testing labs. It is recommended to be added when a part change is required to insure good heat conduction to the sensing bulb. This as related to the wells getting some corrosion on the water side and not being able to give good heat transfer.

When I was with the gas company we ran a series of tests on actual water temperatures versus temperatures detected by controls. We tested strap-ons, direct immersion and wells. The most accurate as I am sure you guessed was direct immersion, next was wells and last strap-ons. We tested both new wells and old wells, wells without compound and with it. The results with the compound on old wells versus old wells without we found a temperature difference of an average of 7 to 10 degrees. Example no compound, well temp 180, actual water temp 185 same well with compound actual water temp 180 well temp 180. So it is more accurate but not to any degree that I would get worried. I dug those figures out of my old papers in my archive. When this discussion started I could not find the papers with those test results but I kept digging around and finally found them. My conclusion is maybe the compund is not necessary, however what is the liability if you do not use it and some temperature overide problem occurs???

I was also told that old compounds versus the new stuff that it was a different make up and should not solidify. I believe someone from Honeywell told me that back in 1994.

radioconnection_2

liability?

What does the manufacturer say to do?

Pete

hr

depends on how well the sensor fits

into the well or socket. Seems whenever I come across a wild control or aquastat it's because the sensor is in an air pocket and not touching the well at all.

I'd rather a strap on sensor personally. Hard to beat the control accuracy provided by controls tekmar builds. Their sensors are predominatly strap on style.

Electric water heaters use strap on stats and the sensor element doesn't even touch the tank wall! They have been around for years and years.

Insulation around the sensor is important with strap on stats, of course.

hot rod

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J.C.A._3

The \"new\" stuff.....

Immersion sensors/bulbs with fluid, and the like are finally going to be toast soon!

The invention and implementation of the thermister is the best thing that could have ever happened to our fine industry.

Something so simple...yet so accurate has made the possibilities endless...and the control manufacturers are finally starting to see the benefits, and using it to their advantage.(Re: Honeywell has gone to them....and they were about the last holdout with the bulb and tube).

That paste is a waste! They call it "heat transferring compound"...I call it a definite sale(AKA Honeywell welding paste)...as when it's used, you're guaranteed to have to replace the whole control....It worked for them...not so much for us....at 2 in the blessed a.m. .

Brad, feel free to keep specifying it...it works for us installers quite well.( no pun intended:P ) Chris

TMiller

Conductive Paste

What about using synthetic wheel bearing grease? It is supposed to transfer heat from races to bearings (and vice versa). It won't harden and wont thin with heat.

Mike D_7

Heat transfer compounds

I'm a retired racer/fleet mechanic. MotorCraft makes silicone grease in a tube. It's called Dialectric grease. it's used as a heat transfer compound when replacing electronic components, for coating electrical connectoins to keep out moisture and prevent corrosion. And last but not least, as a high temperature lube for disc brake sliding parts.
Unlike Never-Seize (The mechanic's best friend) it is non conductive and as a bonus it doesn't seem to ever harden. It won't flow like Vasaline would at high temperatures either.
I've used it for many years when replacing 10K resistors and capillary bulbs, and it's properties were the same many years later.
Hope this is useful to you.
Mike D

Kevin_in_Denver_2

Thermally conductive adhesive

Can anyone recommend an adhesive that might help heat conduction between a pipe, say, and an aluminum plate?

Chas_2

Thermal Glue

Check out Arctic Silver. They make heat transfer combounds and glues. The glue is strong and takes heat. They make two kinds. I bought this stuff and it seems strong.

http://www.arcticsilver.com/arctic_silver_thermal_adhesive.htm

Roland_4

Heat Transfer

Hi Kevin,
I have used this with great results in electronic work:PERMATEX High Temp RTV Silicone Gasket Maker. I think you could experiment with any type of silicone adhesive just be aware that once it cures, thats it!

Mike T., Swampeast MO

Here's a silicon-based Heat Transfer Compound typically used in electronics between a power transistor (or similar) and a heat sink. Does not harden.