Asking For Advice- Lubricate Under Hot Water

Joined
Apr 4, 2020
Messages
6
Location
Detroit, Michigan USA
Hello All!
We have a steam humidifier on our home. (Basically is is a tank with water that boils. The air handler picks up the steam and sends it into the mini duct system we have for air conditioning. White Rodgers HSP model) It has two safety floats whose job is to stop the heater if the water is too low or too high. They are float balls on stainless steel arms. (Photo attached)

Our problem is that, despite the lime filter on the water inlet line, the float arms get lime coated in short order. When the are coated, the balls stick.
I've tried coating the arms & inside the float sleeves to try to keep the lime from sticking. Anything I've tried washed off due to the hot water in which they live.

Here's What I've Tried:
Automotive mineral oil
Automotive synthetic oil
Differential grease
Hydraulic oil
HyPer Lube paste
Car Wax
Bees Wax
Moly Bearing Grease
Synco Super Lube
Petroleum Jelly
Teflon Sleeve over the arms

Hoping to use something I have in the shop, I thought about Never-Seez type anti seize paste. I have copper & silver available. My other thought was white lithium grease.

Do you all think one of those would work? If not, do you have any ideas of what to use?

Thank You for helping our and for educating! I appreciate your knowledge sharing.
Enjoy This Day,
Paul

Floats.JPG
 
Problem is everything like you are using melts off. You need to think of something that can survive boiling water for a LONG period of time and not hold the calcium. OR you could just use soft water. That way, you only have water soluble sodium salts present. That may be the best way to go.
 
I wouldn't expect anything you tried to work. One candidate is an NLGI 2, preferrably NLGI 3, silicone gel. You might want to consider food grade. You might find this as silicone grease, silicone petcock grease or silicone valve seal lubricant.
 
Dow Molykote 111 grease (Home Depot or Amazon) would get my vote for this application. It is made specifically to not wash out in water and 212 degrees is well within its temperature range. We use 111 grease at work for seals and o rings in water filtration equipment and it is always still there when we disassemble for maintenance, sometimes as long as 5 years later. It is a silicone grease and does not actually contain Moly. That is just the brand name for marketing.

As others have commented, though I don't think the grease will solve your problem. Any time you are continuously boiling water out of a pot the minerals are going to precipitate out when they get too concentrated. Softened water will change the precipitation point and produce softer scale, but unless you use totally demineralized water or purge the sump before the minerals get too concentrated, scale happens.
 
Hello All!
Thank You for taikng time to reply with many very helpful comments & product suggestions. I sure appreciate your advice.

On your humidifier do you have a flushing timer that empties the humidifier to flush the minerals down the drain to limit build-up.

You've got me thinking about a One-Two Punch attack...
Concentrating on adjusting the factory purge timer may be my first task. I'd also try some of the lubricant suggestions you all provided.

The timer gets limed up and stops draining- even when set for daily, complete drains. Perhaps simply changing to twice a day is the solution.
Or, perhaps I could retrofit it with a solenoid that has a larger bore. There must be a lot of lime in Detroit water. (You should see the tea kettle!)


~ you could just use soft water.
Great idea, but SWMBO, the Budget Boss, would shoot me if I bought a water softener, so that's out.If we needed one for the other household water, it would be an easy sell.
I have a de-ionizing filter and a lime filter, but enough still escapes to cause grief. Oh Boy! Maybe a second de-lime filter in series is a good plan.

Softened water will change the precipitation point and produce softer scale, but unless you use totally demineralized water or purge the sump before the minerals get too concentrated, scale happens.

From what I learned working on cooling tower pumps, this makes perfect sense. Scale would coat everything if the heating guys didn't keep up with treatment chemicals.

Thanks for the suggestion of CRC Sl35610, Sangglefoot. I forgot to put it in my list of fails. I suppose the steam melted it off, but I use it on many other items with great success. I also forgot Taylor Lube on the list of no-go products.

Next, I will try the N-1000 or a high temp silicone grease, as suggested. Can't hurt.

But, from what you all suggested, it seems my best bet is to keep up with timed sump draining, add the shaft lube and manually de-lime it monthly during humidifying season.

If all else fails, perhaps I could make a probe type water sensor for a secondary low water safety. I'd make one that can have the probes very far apart so they don't get "jumped out" by the lime.
It should be an interesting experiment, if nothing else.

My timing for this post is poor, so next heating season, I'll be sure to post what worked for us.

Thanks Again To All!
Paul

PS: I tried & failed to figure out how to be notified by e-mail when there is a reply to a thread I'm watching, like this one. Is it possible on this user group?
 
how about RO water? could also use it for fridge ice and drinking water.

usually reduces minerals by at least 10x.
 
Your idea is worth good consideration Rand.Thanks!
I suppose it would benefit our health as well should we send it to the kitchen too.

For the humidifier, I'm not sure, but I think the RO's polishing filter adds stuff back to the water. Maybe the humidifier feed line can tap off before that filter (More study planned)
 
Torture Test Update-
In case anyone stumbles on this thread in the future, I did some short term torture testing. The tests were for wash-off and for how well they let the floats slide. I couldn't test long-term lime prevention. Next fall, when the machine is in use, I can to weekly checks to find out which one worked best for preventing build up.

To Test Wash Off of Various Lubricants:
Some stainless steel parts were suspended in boiling water. The parts were coated with various items from all of your suggestions. The parts were allowed to boil for an hour.
Most of the products washed off.

The copper anti seize did not wash off. It was the most tenacious of all tested items.
NLGI 3 silicone left a coating. Fiebing's liquid 100% silicone also left a coating. (It's a shoe waterproofer.) Camp Dry, also a shoe product, left some coating.

To Test Float Sliding:
Each float shaft was coated with one of the products that didn't wash off in the boiling test, then washed off manually before the next test.

Anti-Seize paste, which was the one I thought would work best- didn't allow the floats to slide when the water was cold. Then the proverbial light bulb in my head went on. The tackiness of the paste was beneficial when I used to have to hold large, rather heavy, vertical pump gaskets in place while aligning the pump shell halves.
NLGI 3 silicone, Camp Dry and Fiebings also didn't assist with sliding. I think that's because the coating is very thin.

A Surprise:
I have an automotive engine product called Hy-Per Lube that I use on open gears on one of my machine lathes. It is ultra tacky, so I ignored it for this application. Until now...
For some reason, this let the floats slide very easily when the water was hot or cold. It also did not wash off. I sure was surprised.
On dry parts, it's super sticky, so I was very surprised.

Airborne Odors:
A last minute thought was to have a product that would not, when wash-off floated on the hot water, send odors into the airstream.

Hy-Per Lube didn't leave any oil slick floating on the water, so it may be good for the float shafts in thin application.
Some silicone did float, but there was no detectable odor.


In the fall, I think I'll give this the one-two-three-four punch:
1) Thin coating of Hy-Per Lube on the shafts upon which the floats slide.
2) Liquid silicone on the float bodies & tank walls to prevent lime build up. It had no odor, so some wash off should not be noticeable.
3) I'll set the flushing timer for longer draining of the tank.
4) Weekly inspections for lime scale build up.

Time Will Tell! I'll be sure to update this when the machine is in use.

Thanks Again Everyone for helping with this decision. It has been a learning experience and I now have some new lubricants in my arsenal, all of which will prove helpful in various work and home projects.

Please have a safe & peaceful Easter, Passover & Ramadan during these unusual & challenging times!
Paul
 
Here's some friendly advice if you really like this thing and want to use it trouble free pretty much for life

If you don't have the skills, I'm sure you probably know ( or know someone who knows) an electrician- even if you have to pay- it wont be much.

Go to Grainger/McMaster of any number of suppliers and get a N/C valve for the water and magnetic float switch (with the contacts above the float) and set your levels and wire it in.

That works with all kinds of crud filled systems like barometric legs on vacuum pump systems to cooling tower sumps fed by pond water.

All your problems and concerns will go away.
 
Thank You ABN_CBT_ENGR for your brilliant & simple-to-implement idea!

Being a master electrician (with well over 40 years' experience designing and building control systems), I really should have thought of this one myself years ago.
With me, sometimes the simplest solutions get shoved aside for doing things the hard way!

Thanks Again & Enjoy This Day!
Paul
 
Back
Top