Water level switch?

[TPES]

I have the task of installing a pump under ground at the side of a lift shaft that is surrounded by water, the builder has asked for a permanent pump installed with a float switch so that when water reaches a set level the pump kicks in automatic..

Does anyone have any experience with this type of level switch and can recommend just what I'm after?

 

[poirot]

Installed some years ago, the pumps come with the float switch connected, just needs a supply. Try screwfix or toolstation for a basic pump with floatswitch otherwise enquire with your wholesaler.

 

[accordfire]

These are available from Icenta - used a few in the past, and pretty reliable.

Buoyancy level switch package with compact relay controller, from icenta Controls UK

Will typically actuate the pump once it reaches the desired level and has a 10A relay @250VAC.

 

[johnboy6083]

float switches are the cheapest option, but they can and do go wrong. the key is reducing the number of cycles.
for example, if the pump is in a small tank/area to be emptied, then the pump will empty the tank, and then cut out. the water will then fill the tank, and pump will kick in again, so to reduce the number of times it has to do this, there are a few options.
1)increase the size of the area to be emptied
2)choose a pump that will empty the area slowly, but no too slowly, that the area will overflow.
3) govern the pump back so that it empties the area slowly (if you get the pump to pump water, anbd then close the valve slowly, eventually you will hear a change of pitch from the motor. Once past this point, you are liable to damage the pump, and it will cavitate)
4)use a liquid level relay and level probes, which can have a time delay built in.

also, ensure that your sump pump has a non return valve directly after the pump, and a normal valve (ball valve) directly after that. this ensures that when the pump stops, the water doesnt syphon back, and the ball valve is so that you can maintain the NRV without getting wet.

This is assuming you re using solid pipe, and not layflat hoses.

john

 

[Marvo]

I would also use probes and a liquid level control and run the pump via contactor. For critical areas like lift shafts and basements we usually install two level systems, two contactors and two pumps to provide redundancy should one fail. We usually fabricate a small stainless steel perforated barrel which the probe assembly screws into to stop debris like plastic bags etc interfering with the probes.

The type of equipment you're looking for is available at agricultural suppliers, irrigation suppliers and general electrical control equipment outlets.

 

[lewlec]

hi

i would also go for the liquid level control option, float switches can be unreliable. i think we use to use fantini level control relays.

regards
gary

 

[TPES]

I would also use probes and a liquid level control and run the pump via contactor.

Would you say the same as what accordfire recommend in his posted link.. ?

Appreciate all your replies

 

[Marvo]

Would you say the same as what accordfire recommend in his posted link.. ?

Appreciate all your replies

Hmmm, kinda. The float switches in the linked page have built-in electronics by the look of it. I prefer dumb s/steel probes in the shaft and all the electronics together in a remote enclosure. Old fashioned I know but it just makes life easier for testing and commissioning.

The probes are on page 166 of this catalog
The liquid level control is on page 157 same catalog.
The pump protection relays are also useful on page 163.

Please note this is a South African supplier, you would need to source a local equivalent if you're in the UK.

 

[johnboy6083]

Agree with level probes. If you find the gear, post on here and I can explain how to set them up. Also agree with 2 pumps, master and slave.

 

[johnboy6083]

Just had a look at the links above, seems like the same gear (different manufacturer) that I used to use. Didn't realize how expensive it was though! I meggared one once! Lol

 

[TPES]

Agree with level probes. If you find the gear, post on here and I can explain how to set them up. Also agree with 2 pumps, master and slave.

I will do, just hope I find the right equipment for the job.. Thanks

 

[Marvo]

Just had a look at the links above, seems like the same gear (different manufacturer) that I used to use. Didn't realize how expensive it was though! I meggared one once! Lol

If you're referring to the prices in my linked catalog, they're in South African Rands (ZAR). There's about ten ZAR to one UK Pound.

The probe head with three x 1 meter s/steel probes works out at about 12 quid. The liquid level controller is about 30 quid with the 11-pin base.

You'll probably pay less in the UK, we pay premium prices in SA.