# Ranco electronic temperature control.



## RandyS (Feb 6, 2015)

I wired up a Ranco ETC-111000 about six months ago to control my heaters. Lately the controller hasn't been able to hold the temperature steady. When I tested the sensor I found it's no longer reading the correct temperature. I've done some research on this unit and now it's looking like the thermistor may not be waterproof although my findings are fairly vague.
Has anyone had this issue? Does anyone know where I can buy a water proof sensor for this unit or a way to make the replacement waterproof?
Thanks.


----------



## sparky4056 (Sep 1, 2014)

There are a couple of options for water proofing it. You can use some pvc heat shrink on it or put silicone where the probe meets the cord (I've read this is the spot where water causes the problem). I don't know what kind of filter you have, but I plumbed a stainless steel thermowell into the intake of my canister and just placed the probe in that, so not only is it water proof, but in is also not seen.


----------



## RandyS (Feb 6, 2015)

Thanks Sparky.
I'm using the sensor at the opposite end of my sump from the heaters. It drops in vertically from the top.
The thermowell looks like a clean way to go but the heat shrink may be easier. How do you seal the end of the tubing?


----------



## sparky4056 (Sep 1, 2014)

Leave a little extra of the heat shrink hanging off the end of the probe, heat it, and then pinch it with a pair of pliers. This should create a water tight seal. Let me know how it works out for you, I'm thinking of going this route on my next setup because it does sound easier.


----------



## RandyS (Feb 6, 2015)

sparky4056 said:


> Leave a little extra of the heat shrink hanging off the end of the probe, heat it, and then pinch it with a pair of pliers. This should create a water tight seal. Let me know how it works out for you, I'm thinking of going this route on my next setup because it does sound easier.


Will do. I ordered the tubing this morning.


----------



## RandyS (Feb 6, 2015)

Hey Sparky
My tubing came yesterday and I installed it over my new sensor last night. It was a fairly easy job and works pretty good. I DID need to do a little experimenting to determine how hot the tubing needed to be to get a water tight seal. It needs to be just shy of burning. I then used a long pair of needle nose to compress it. The pliers had a long section in the jaws that were void of teeth. I've got pictures if anyone's interested.


----------



## sparky4056 (Sep 1, 2014)

It's weird how some people don't have any issues just submerging these sensors and some need to waterproof theirs. I'm glad this method worked out for you.


----------



## RandyS (Feb 6, 2015)

Well, I'm again having trouble with my controller.
I always check the water temperature daily. The other day the temperature display on the Ranco was showing 90° but it wasn't energized and the water temp had dropped down to the low 70's. I pulled everything out figuring I must have had another sensor failure even though I was confident I had a water tight seal on the shrink tubing when I installed it. Now that I have everything on the bench it's working perfectly. Upon inspecting the tubing around the sensor even that looks good. Go figure.
I kinda figured all along these Ranco units were bullet proof but now I'm not sure what to think.
Has anyone had any issue like this before?


----------

