Mercury tilt switch

[Tricky1]

Hi I hope someone can help,I am a keen on diy but I have a real problem.

I am ok a well I have a water pump in the garage and also a new switch box.

I have a mercury tilt swich above water tank in loft housed in a green plastic box. Every time we have hot weather the switch fails and we have no water-I can use over ride in garage.

The tilt switch will not activate even if I get in loft and operate tilt manually.I have been told they cant fail but it clearly does every time it's sunny and loft gets hot. When cool weather returns it's fine again.

What's going on and what can I do about it?

I'm stumped thought about trying to insulate box from heat but not sure if that's possible.

Thanks guys,

Tricky1.

 

[The Godfather]

Are you saying you have to replace it?

Or it fails only in hot weather?

If its the latter, is it normally closed operation, if so I suspect the mercury is expanding and can never give a N/O operation.

The Godfather

 

[Evans Electric]

What is the tilt switch for ?

 

[Tricky1]

Hi I am on a well for my water the switch is triggered by a float in the tank that is part of the mercury tilt switch only happens in hot weather so we have no water how can I resolve problem?

 

[The Godfather]

The Don is not sure of a solution, other than try a alternative switch, one that is unaffected by the temperature issue.

There are alternatives to the mercury switch.

Any chance of a photograph?

regards

The Godfather

 

[Evans Electric]

I presume the switch tilts when the tank level is low and starts a pump ? Mercury has a high coefficient of linear expansion ( I have'nt used that phrase for 300 years) perhaps it just needs adjusting. The heat seems to the contrbuting factor, when it tilts does the mercury cover the two contacts in the tube ? Is it tilt to make or tilt to break ?

Deke

 

[a1]

Any chance of a photograph?

I'd second that.

 

[batty]

They say mercury drives you mad.

:^O

 

[The Godfather]

They say mercury drives you mad. :^O

The Don is amused.

The Godfather

 

[Andy™]

They say mercury drives you mad. :^O

and opium drives wallabies mad!

 

[green-hornet]

we have a problem with wallabies entering poppy fields, getting as high as a kite and going around in circles," Lara Giddings told the hearing.

"Then they crash," she added. "We see crop circles in the poppy industry from wallabies that are high."

LOL

Sounds like the people going to Glastonbury Festival.

Back to the original post, if the weather is effecting a mercury switch then I would suspect one of two things.

A. The heat is effecting the mercury directly causing problems.

B. Dry hot weather means the water table from which the well is drawn from could be lower than the float can detect.

You may need a specialist engineer to find the problem, or could be that the switch needs to be replaced, obviously the latter option would be cheaper.

 

[bryn]

sounds like mercury expanding and sending switch N/O most systems use Flyght pump float switch have found these to be very good not too expensive and used on most commercial water and sewarage systems.

 

[The Godfather]

sounds like mercury expanding and sending switch N/O most systems use Flyght pump float switch have found these to be very good not too expensive and used on most commercial water and sewarage systems.

The Don is pleased.

The Godfather

 

[bigclive]

As well as the usual float switch you can get a type that is basically a switch with a short line down to a weighted float in the tank, so when the water is low it pulls down on the cord attached to the switch and turns it on.

By the sound of things it would be worth checking to see if anything is fouling the existing switch like thermal expansion causing warping of a plastic case. Is this an actual floating switch or some other device?

The other option is to use an ordinary light switch and turn it on when the water stops coming out the taps and then turn it off again when the water starts coming through the ceiling.

(Yes that last bit was particularly unhelpful and obnoxious.)

 

[Tricky1]

Thank for the response (ESP the last bit what u say makes perfect sense this is day 6 without water but what can I do to correct problem? It only happens in hot/ humid otherwise it operates fine. It consists of a green plastic box above water tank in loft approx 6inches x 5 x 5 with a mercury switch inside on the outside is a tilt mech with a chord and float on one end and counterweight on the other I can't see any adjusment on the mercury switch and in hot weather it will not kick in even if I get in loft and operate tilt manually. Thought about trying to insulate box from heat but how & why has it gone now it has been fine before. What's the solution will a new switch do the same thing -I have read there is nothing to fail on a mercury switch but that's obv wrong. Thanks again. Tricky1

 

[bigclive]

Can you see the pump to make sure it's submerged? It may have a float switch locally too to stop it running dry if the water level is low.

 

[binky]

What else is in the box???? Mercury tilt switches are generally very reliable, so issue could be with another component in the box??? Suggest you try so basics like making sure all connections are good, solder joints are good etc etc.

 

[paulh]

I think the best advice would be to GIVE US A PHOTO.

Have you tried disconnecting the switch and testing it for continuity?

If you are really not confident I think its time for a visit from a electrician Blushing

 

[Evans Electric]

Have you sorted the tilt switch yet , Tricky, everyones dying to know the outcome.

 

[Andy™]

Have you sorted the tilt switch yet , Tricky, everyones dying to know the outcome.

i can think of better things to die about