Level control switch

[Esso49]

Has anybody fitted a level control switch to their water storage tank so that if the water level drops it automatically cuts the circuit to the water pump hence protecting the pump ?   I have looked around for a long time  but never come across a satisfactory item in the main stores such as Global etc so would be interested if anybody has fitted this, what make and where purchased ? I know I can import one but rather buy locally if possible.

[kamalabob2]

If the OP shopped at a water pump focused store in Isaan this would be explained that ALL household Mitsubishi water pumps and ALL Hitachi residential water pumps have a built in sensor.  Example: Your PWA or village water supply was out for a few days or your submersible well pump stopped pumping into your storage tank, and your 1000 liter water storage tank was drained. The modern household Mitsubishi or Hitachi water pump will cut off and not be damaged. You will figure it out that you need water in your water storage tank.   

 

Now liquid level controllers are readily available for your water tank to determine when they are filled. Global might have a Mitsubishi pump PC on duty to explain the pumps on offer at Global House made my Mitsubishi have a built in sensor. 

[eyecatcher]

This is the electronic one we just had fitted.

A far cry from the ballcock days!

[Crossy]

All the big-box stores (HomePro, MegaHome, Global etc etc) have them, but if you don't know what the box looks like you could be in trouble, they're not always where you expect them to be.

 

Two main types, single float like @eyecatcher shows above and a more "adjustable" two-float unit. Both can be wired to stop the pump if the level is too low.

 

As noted in an earlier post many pumps do have run-dry protection (none of ours do of course).

[Esso49]

5 hours ago, kamalabob2 said:

If the OP shopped at a water pump focused store in Isaan this would be explained that ALL household Mitsubishi water pumps and ALL Hitachi residential water pumps have a built in sensor.  Example: Your PWA or village water supply was out for a few days or your submersible well pump stopped pumping into your storage tank, and your 1000 liter water storage tank was drained. The modern household Mitsubishi or Hitachi water pump will cut off and not be damaged. You will figure it out that you need water in your water storage tank.   

 

Now liquid level controllers are readily available for your water tank to determine when they are filled. Global might have a Mitsubishi pump PC on duty to explain the pumps on offer at Global House made my Mitsubishi have a built in sensor. 

Basically that is crap.  That is what they say but unfortunately by the time they shut down the damage is done.  So would appreciate an answer to my original post.  If you can not directly answer the question then fine.

[eyecatcher]

5 minutes ago, Esso49 said:

Basically that is crap.  That is what they say but unfortunately by the time they shut down the damage is done.  So would appreciate an answer to my original post.  If you can not directly answer the question then fine.

You dont deserve any advice after a comment like that.

[Daffy D]

https://www.lazada.co.th/catalog/?q=water+level+switch&_keyori=ss&from=input&spm=a2o4m.home.search.go.4ccd719cxi4Qp0

 

[Esso49]

2 hours ago, Crossy said:

All the big-box stores (HomePro, MegaHome, Global etc etc) have them, but if you don't know what the box looks like you could be in trouble, they're not always where you expect them to be.

 

Two main types, single float like @eyecatcher shows above and a more "adjustable" two-float unit. Both can be wired to stop the pump if the level is too low.

 

As noted in an earlier post many pumps do have run-dry protection (none of ours do of course).

Hi Crossy.

Seen those but dubious if they really work. To be effective they need a low level switch cut off and a low low low circuit breaker cut.   These ones and others I have looked at do not seem to provide that level of protection so hence the confidence level is low.   After going through 3 pumps and 48000 baht due to the Thai in-laws  lack of commonsense in the last 14 months I shall not be installing another pump for them until I have a reliable low level cut-out.  As I said I could import one, around 21000 baht + import duties for a technically adequate one but was hoping that a reliable one could be available in Thailand.

 

The other posters comments regarding auto cut-out protection is straight from the pumps or salesman's mouth but do not hold water,  pardon the pun, as by then the pump has already undergone mechanical  internal bearing damage.

[Esso49]

6 minutes ago, eyecatcher said:

You dont deserve any advice after a comment like that.

That's ok I was only asking from people with technical competence, but have a nice day anyway thank you

Edited September 4, 2018 by Esso49

[Crossy]

8 minutes ago, Esso49 said:

Seen those but dubious if they really work.

Both types work just fine, don't overload them with too big a pump (use a contactor) and they last well.

 

We currently have a 2-float one directly controlling a 2 HP pump, big plus is the electrical bit sits on top of the tank so nowhere near the water and the switch is accessible to replace if it fails. I certainly wouldn't be paying 21k Baht.

 

Ours is almost exactly like this one, note this one is only 5A ours is 15A.

https://www.aliexpress.com/item/Hot-Sale-1-2M-Controller-Float-Switch-Liquid-Switches-Liquid-Fluid-Water-Level-Float-Switch-Controller/32820556032.html

 

[Esso49]

24 minutes ago, Crossy said:

Both types work just fine, don't overload them with too big a pump (use a contactor) and they last well.

 

We currently have a 2-float one directly controlling a 2 HP pump, big plus is the electrical bit sits on top of the tank so nowhere near the water and the switch is accessible to replace if it fails. I certainly wouldn't be paying 21k Baht.

 

Ours is almost exactly like this one, note this one is only 5A ours is 15A.

https://www.aliexpress.com/item/Hot-Sale-1-2M-Controller-Float-Switch-Liquid-Switches-Liquid-Fluid-Water-Level-Float-Switch-Controller/32820556032.html

 

Thanks Crossy and will look into this.  See it is only IP65 rated so would need to have some protection as our tanks are exposed to the elements.

[Crossy]

1 minute ago, Esso49 said:

Thanks Crossy and will look into this.  See it is only IP65 rated so would need to have some protection as our tanks are exposed to the elements.

Ours is also out in the elements, no issues with the damp getting in, IP 65 is just fine.

 

We have IP 54 kit (non essential) up on the Purple Line platforms, no noticeable water ingress even after the (rain related) failure of the main power yesterday. 

[sometimewoodworker]

18 minutes ago, Esso49 said:

Hi Crossy.

 Seen those but dubious if they really work. To be effective they need a low level switch cut off and a low low low circuit breaker cut.   These ones and others I have looked at do not seem to provide that level of protection so hence the confidence level is low.   After going through 3 pumps and 48000 baht due to the Thai in-laws  lack of commonsense in the last 14 months I shall not be installing another pump for them until I have a reliable low level cut-out.  As I said I could import one, around 21000 baht + import duties for a technically adequate one but was hoping that a reliable one could be available in Thailand.

 Agree that the pump run dry protection is not good enough to function as a regular off switch. Also 

 

5 hours ago, eyecatcher said:

This is the electronic one we just had fitted.

A far cry from the ballcock days!

This version is not designed to do the job the OP wants, all though it may be adapted for the job it would not be ideal as it is much less adaptable than the less expensive version 

this version is widely available for under 400 Baht 

 

howeve as supplied it does the opposite job to the one the OP wants. The answer would be to add enough string so the bottom switch on point is near the bottom of the water tank, then wire the water pump through a normally on contactor so that when the float switch is on it energies the contactor which then cuts power to the pump.

This would provide an automatic way to do what the OP wants. If you want to require a manual switch on then a little creative wiring of a dedicated RCBO that is tripped by the float switch would work, though I don't know if regular trips of an RCBO will require replacement 

[NanLaew]

2 hours ago, Esso49 said:

Basically that is crap.  That is what they say but unfortunately by the time they shut down the damage is done.  So would appreciate an answer to my original post.  If you can not directly answer the question then fine.

I have lived in 6 homes over a cumulative ~18 years in LOS. All but two of those had a Mitsubishi water pump installed and all homes were blighted by random low pressure or no water mains supply. I never had a pump burn out and the current one is coming up to 11 years of varying abuse which includes about 6 years of being exclusively buggered about by the in-laws. The built-in thermistor happily cuts pump power a few minutes after it runs dry and the same thermistor keeps the power off until it has cooled down. The only pump that needed replacing was a cheap Chinese clone in our last rental stay that the landlord was happy to replace... with another cheap Chinese clone. The other pump was a Davey that I brought back from work in Australia way back when I built my first home and local choice was very limited. According to the wife of the guy that bought that home, it's still working as well.

 

 

Edited September 4, 2018 by NanLaew

[sometimewoodworker]

1 hour ago, sometimewoodworker said:

This version is not designed to do the job the OP wants, all though it may be adapted for the job it would not be ideal as it is much less adaptable than the less expensive version 

this version is widely available for under 400 Baht 

 

howeve as supplied it does the opposite job to the one the OP wants. The answer would be to add enough string so the bottom switch on point is near the bottom of the water tank, then wire the water pump through a normally on contactor so that when the float switch is on it energies the contactor which then cuts power to the pump.

This would provide an automatic way to do what the OP wants. If you want to require a manual switch on then a little creative wiring of a dedicated RCBO that is tripped by the float switch would work, though I don't know if regular trips of an RCBO will require replacement 

 A correction to the last post. It in fact has 2 ways of connection the A connections are usually off the B are usually on, both are switched by the water level 

 

So so this is exactly what is needed. You can still set up an RCBO to trip.

43 minutes ago, NanLaew said:

The built-in thermistor happily cuts pump power a few minutes after it runs dry and the same thermistor keeps the power off until it has cooled down. 

While that will certainly work for an occasional run dry situation (my pump has the same function) it will automatically start with no water in the system and keep on doing that and for sure continually running a dry pump till it overheats then cutting out is going to trash the pump quickly.  

[maxpower]

Switching off a pump before supply tank runs dry is by far the best method of protecting pump seals. Timed low flow or  pressure is the next best.

As I remember, most of the common float switches found in Thailand have >10A capacity with changeover contacts. If the pumps power requirement is within the float switch capacity then it can be wired directly as normally closed. There is no worry about contact wear because the switch will only operate as low level cut out.

 

At our 20K litre potable water tank we use a regular float switch to trigger a low level alarm. The switch sits about 1M from the bottom tethered to a pole and weight. Cable passes through seal gland to external junction box.

 

For smaller tanks with less high low differential, a switch with sink weight will assist in adjusting to operate as low level detection.

 

 

Float switch with sink weight.

 

 

String and double float switches require a hole between outside and inside of tank for float string to pass. The lever switch is mounted externally in a simple capped off enclosure with crude cable entry.

 

String and float switch

 

 

 

 

[Esso49]

1 minute ago, maxpower said:

Switching off a pump before supply tank runs dry is by far the best method of protecting pump seals. Timed low flow or  pressure is the next best.

As I remember, most of the common float switches found in Thailand have >10A capacity with changeover contacts. If the pumps power requirement is within the float switch capacity then it can be wired directly as normally closed. There is no worry about contact wear because the switch will only operate as low level cut out.

 

At our 20K litre potable water tank we use a regular float switch to trigger a low level alarm. The switch sits about 1M from the bottom tethered to a pole and weight. Cable passes through seal gland to external junction box.

 

For smaller tanks with less high low differential, a switch with sink weight will assist in adjusting to operate as low level detection.

 

 

Float switch with sink weight.

 

 

String and double float switches require a hole between outside and inside of tank for float string to pass. The lever switch is mounted externally in a simple capped off enclosure with crude cable entry.

 

String and float switch

 

 

 

 

Much appreciate your input thankyou

 

[NanLaew]

13 hours ago, sometimewoodworker said:

 ...

While that will certainly work for an occasional run dry situation (my pump has the same function) it will automatically start with no water in the system and keep on doing that and for sure continually running a dry pump till it overheats then cutting out is going to trash the pump quickly.  

Yes, it appears that the OP's issue is an 'unattended' installation and the in-laws can't be arsed to turn the pump off when they know there's no water. lazy buggers but par for the course.

 

If they were my lot, I wouldn't invest in any more hi-tech solutions as absolutely nothing is Isaan-proof. Let them bugger about with water tankers and wells and going dirty instead. They won't mind too much.

[kamalabob2]

The Op has not posted what brand and model water pump he has experienced issues. I have owned a few water pumps in the past 13 years in Thailand. NanLaew has posted a very valid comment regarding Mitsubishi water pumps. I have spoken face to face last week with Senior management of Mitsubishi Electric Automation including Mr. Somchin Leelaket the Vice President.   I have his card, email address and phone number. If the OP has an issue with a Mitsubishi water pump made in Thailand or Japan by Mitsubishi Electric Kang Yong Watana Co or Mitsubishi Electric Automation Co Ltd I am in a fair position to get a technical answer. Perhaps the OP could post a photo of the pump he owns that has experienced trouble. I also own liquid level controllers but not for the use the Op has an issue. My experiences with water pump installation and repair services in Buriram have been excellent perhaps due to buying name brand pumps and paying a competent team to install the pumps and water tanks at my homes. The Mitsubishi INVERTER model Super Pump is what I have selected for my village home.