Attaching temp sensor in PVC pipe.

[Dirk]

just Hey, if it works that's good enough for me!

Hard to argue that. I saw that some of those are pressure rated. Would any generic one be? Or does the OP need to find one for a pressure application?

Would it just clamp to his sensor's housing? Such that he wouldn't need the washer and nut that came with it to hold it in place?

What about the threads? Would half of the sensor (the threaded part) be outside of the gland (and the water)? What would that do to the temp sensing (especially if those threads are gunna get hit by the sun)?

Or are you suggesting he not use the sensor he found and go with a different one?

I'd still trust my threaded PVC cap idea better. The cap is threaded, the sensor would be held in place with threads and nut. If I'm understanding a cable gland correctly, it'd just be the friction of an o-ring holding the sensor in place against the water pressure. An o-ring that is outside, subjected to the elements. Hmmm...

With the threaded PVC cap, all of his sensor would be in the water (except the part of it that doesn't need to be).

 

[setsailsoon]

What @Darin says... "Cable Gland"
Working great for me. +6 years. No issues.
Amazon.com
View attachment 586727

Looks like it seals right around the probe itself with compression-type fitting. is that correct? I couldn't tell 'till you posted that it would snug up enough... this looks great and 6 years with no leak is plenty for me.

 

[MyAZPool]

Looks like it seals right around the probe itself with compression-type fitting. is that correct? I couldn't tell 'till you posted that it would snug up enough... this looks great and 6 years with no leak is plenty for me.

Correct. It is a compression type fitting. Thermistor goes inside and then just tighten up the nut. All there is to it.

In addition in my case, I used a 2" slip x 1/2" fem threaded sch40 reducer bushing installed at the tee fitting..
If I recall, I picked it up at Home Depot.

 

[Newdude]

Thanks, I didn't have time to review the total thread

Exactly why folks should start their own discussion and not resurrect a years old thread thats pages deep and the original participants are probably long gone.

 

[Darin]

Or does the OP need to find one for a pressure application?

No any of them will work. there is only a couple of PSI on the back side.

 

[MyAZPool]

Hey, if it works that's good enough for me!

***EDIT*** especially for @MyAZPool he's got the neatest install I've ever seen!

Thanks C.
Just goes to show ya that even a blind squirrel finds an acorn every now and then.
r.

 

[strategy400]

Well, it does exist, if you can get it shipped to you and have it show up matching the picture.

1-1/2 in. Schedule 40 PVC Cap/Socket End Plug Pipe Fitting NSF SCH40 ASTM D2466 1.5"

247Garden SCH40 PVC 1-1/2" End Cap/End Plug NSF Schedule-40 Pipe Fitting

www.247garden.com

View attachment 586501

Alternative: there are threaded end caps that might also work. This would be useful to later get at the sensor without having to cut out a glued-on cap.
View attachment 586502
If their on-line spec's are to be trusted, both of these are rated for 150 PSI.

The nice thing about the threads is you could later replace a faulty sensor, or change it altogether to some other brand/model that wouldn't have to be of the same diameter. You'd just replace the threaded cap and drill whatever hole you needed. You really should have a way to get at the sensor's nut, which is going to be on the inside of your plumbing.

I like the flat cap. In my experience threads end up leaking, but it might be worth a try.

 

[strategy400]

Why not just use a thermowell with a 10K thermister with a 1/2" tee you install anywhere convenient? No complicated leak source to deal with. Even SS thermowells are cheap. @Katodude showed me this at his pool... temp diff across the well wall is insignificant and you can trim that out with calibration.

Chris

I'm using a ds18b20 in my application. 10k won't work. If I could use 10k I'd just drill a hole with an oring and hose clamp.

 

[strategy400]

Thanks, I didn't have time to review the total thread. I wouldn't worry about a high quality SS thermowell. I've seen them used for industrial boiler feed water making very high temp super-heated 1500 psi steam. Contaminants are controlled to virtually zero with anionic and cationic beds that are regenerated with strong acid and caustic. If you get any contamination it can easily cause an emergency shutdown that almost always costs $1MM to fix. But everybody has to make their own choices and I get that. Plastic is not very conductive so "calibrating out" the temp difference could be an issue.

Chris

The problem isn't corrosion, it's being electrocuted.

 

[strategy400]

The flat cap is $13 to ship. Guess I'll try to make my rounded one work. I'll add extra pipe on the tee in case I have to lop it off and start over

 

[setsailsoon]

The problem isn't corrosion, it's being electrocuted.

"Not for use in salt water or other corrosive environments. These are not IP rated," from their data sheet. Even a non-salt pool can have up to 1000 ppm from a year's worth of chlorinating. Maybe will work and for $10 worth trying but if it's an electrical hazard... maybe not.

 

[strategy400]

"Not for use in salt water or other corrosive environments. These are not IP rated," from their data sheet. Even a non-salt pool can have up to 1000 ppm from a year's worth of chlorinating. Maybe will work and for $10 worth trying but if it's an electrical hazard... maybe not.

Even more reason to use a pvc thermowell.

 

[strategy400]

I have an old iPad shoved in a drawer around here somewhere. I could repurpose it in a picture frame by the doorway leading to the pool and display the water temp.

 

[setsailsoon]

I have an old iPad shoved in a drawer around here somewhere. I could repurpose it in a picture frame by the doorway leading to the pool and display the water temp.

Very cool!

 

[strategy400]

Progress update. I used one of those step drill bits to make the hole, which didn't do the cleanest job so I finished it off with a round file and some sandpaper. I suspect it will seal up OK. There is a rubber gasket on the inside.

 

[strategy400]

If necessary I can cut out some pipe and insert a threaded connection later

 

[strategy400]

So I plumbed this loop to send water to my solar panels, but I screwed up by putting the check valve directly over the solar valve, not realizing the actuator would get so close I can't put the valve handle back on. I also think any water dripping from the check valve drops directly into the actuator shaft. Oops. So I will try to move the check valve over where the green arrow is and insert the thermowell tee where the red arrow is.