Thermocouple lube

[tinnerjohn]

While doing the preseason PM on a unit heater in a water plant today, I had some difficulty removing the thermocouple and pilot line nuts. It appeared to be a dissimiliar metal/high humidity caused problem. I've had the same problem in damp basements. While cleaning the burner tubes, I had time to think (Bad thing to do). What, if anything could/should be used to lube threads? Just thought I'd toss this out and see if anyone has any suggestions, other than remove the moisture source, which in most cases is beyond our control. John

[chillerout1]

dielectric grease or be very careful with anti-seize

[fxb80]

Anti-seize is best, but I'm in the habit of putting a single drop of Zoom Spout oil on pilot line fittings and that seems to help a lot.

[btuhack]

Baso sells a high temp graphite grease for valves and pilot break nuts. It makes the pilot tube connections SO much more easy to deal with.

[tinnerjohn]

Thanks for the input. My first thought was dielectric grease on the thermocouple. I used the zoom-spout on the pilot line, but wasn't sure if oil would mess with the conductivity of the TC. John

[fxb80]

Oil or anything else on the pilot line will have no effect whatsoever on the thermocouple, all of the thermocouple voltage is in the thermocouple copper. A tiny amount of oil or anything else on the thermocouple nut threads will have no effect on the thermocouple either.

[jeremyhall.tech.sc]

While doing the preseason PM on a unit heater in a water plant today, I had some difficulty removing the thermocouple and pilot line nuts. It appeared to be a dissimiliar metal/high humidity caused problem. I've had the same problem in damp basements. While cleaning the burner tubes, I had time to think (Bad thing to do). What, if anything could/should be used to lube threads? Just thought I'd toss this out and see if anyone has any suggestions, other than remove the moisture source, which in most cases is beyond our control. John

graphite powder. you can put it in a pen, similar to a oiling pen. graphite between metals never goes away or wears-out.

[billygoat22]

I would have said petroleum jelly or plumbers grease.

I use antiseize on lots of stuff- condensor and blower motor shafts, bolts on oil burners and furnaces, tried some on the cleanout caps on a furnace yesterday (we'll see next yr or too if they come off cleanly).

Have used no-ox on wire nuts for low voltage on outdoor units. I notice some of the manufacturers now supply grey wirenuts with gell inside them.

[Cooked]

Have used no-ox on wire nuts for low voltage on outdoor units. I notice some of the manufacturers now supply grey wirenuts with gell inside them.

Those wirenuts are readily available at Home Depot or Lowes. I have never used the powdered graphite on a thermocouple but it sounds like a good idea. Just be careful, it's messy as all get out. It turns anything you get it on black including hands, clothes, carpet etc...