Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Float switch with 'push to test'

Float switch with 'push to test'

Float switch with 'push to test'


I have a requirement for a hydraulic tank level (float) switch that can be tested daily for operation.

Customer wants to be able to ‘push to test’ the level switch circuit at the tank, to mechanically check the operation daily.  

We mainly use small optical level sensors, which have proven more reliable than the float switches used in past. Using two or three, optical sensors in a ‘voting’ type circuit is not acceptable to customer. Fluid may be petroleum oil or water glycol.

Proposals have included:
1. mechanical system that pushes down on the submerged float    
2. mounting method to rotate the switch 180 degrees in the tank sidewall so float goes upward and trips the circuit   

Anyone know of a float switch with built in rod or shaft that could mechanically move the float?


RE: Float switch with 'push to test'


Could you mount the switch on an adjustable base that was shifted manually or with an Air or Hydraulic Cylinder. The switch base connection would only have to move enough to make sure the switch was still able to make or break contacts.

Bud Trinkel CFPE

RE: Float switch with 'push to test'

I have not seen such a switch. The closest I have seen is the float type with externally adjustable contacts sold by Murphy. I liked these because I could fine tune the trip point so that a failure would only result in a little bit of oil loss.

To further elaborate on Bud's idea, I would make it as fail safe as possible.
-make sure it can't be held in the up position
-if something breaks in the mechanism, the switch is at the correct height but not too low.
-If the switch moves, I would be worried about the wiring flexing over time. Obviously you want an open to trip the shutdown, but maybe also consider low voltage in case of a short?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper – Data Security and Know-How Protection
Our data is constantly exposed to the danger of being intercepted or stolen as it wends its way over global data networks. Data security measures and measures for protecting intellectual property should not, however, first be implemented when data is exchanged – companies must lay the foundation for these measures within their own organization. Download Now
White Paper – Collaboration in the PLM Context
The influence exerted by the Internet of Things (IoT) means that there is a steadily growing need for collaboration in industry. Partners from new industries and areas of application need to be integrated in cross-company business processes to ensure that the lifecycle of smart, connected products can be managed from end to end. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close