why is my water pump drawing power even when not running?

budgetbuilder

I've asked this question to a few plumbers, the store that sold me the pump, an electrician and none of them at first even understand the probelem which is that the water pump at my well is drawing copious amounts of power even when NOT running. It is not short cycling, which is what they all seem to think I mean when I say that it's running up huge bills. it's working perfectly apart from running up hundreds of euros in electricity bills each month while not even running!!! After my meter was checked by the ESB yet again, the electrician they sent said that there were fluctuations on the circut to the socket that the pump is plugged into. So, I put the pump on a remote control so that there is only power going to it when I want to refil tanks or run a tap. The electricity bill has now shot down to €99, a big drop from the €700 of the previous bill so I'm certain that it's that circut that the problem is on. Now I'm trying to troubleshoot what the problem is before the winter comes because if we get hard frosts and the pump is switched off it will probably freeze solid and burst, just like the previous one did in 2010. I've checked the neutral in the plug for a short and it's all clear. It had a new cut out switch fitted last year but the hefty bills go back at least two years, if not more but have been getting worse and worse. I'm hoping someone on here can point me in the right direction as we had a death in the family a few months ago and have some heafty bills from that to pay for so I can't afford to fork out for a whole new pump which may not even fix the problem. If I'm sure it will, I'll have to find the money somewhere but I don't want to just chuck it away on a hunch that may not fix it. Has anyone heard of this happening before? The pump is a Grundfos, if that's any help.

Zen65

A bit more information might help.

Do you have a schematic for the arrangement, both hydraulic and electrical?
How is the pump called upon to start up?
Is it pressure-switch operated?
Is there a solenoid in the water circuit?
Does the pump have a built-in heater to protect against frost?
Do you have a model number for the pump?

Thanks

Sir Arthur Daley

Is it a dry run or sub pump?

budgetbuilder

Sir Arthur Daley wrote: »

Is it a dry run or sub pump?

It's a surface pump, not one submerged in the well so when it is running it can be heard quite distinctly. The motor does not run when it's not pumping water. Basically, if there is power going to it, it will turn on within a few seconds when I run a cold tap and turn off within a few seconds of turning off the tap once the correct pressure in the pipe and the pressure vessel is reached. As far as I can tell, the only thing that can be adjusted is the cut out pressure by adjusting the screws on the pressure switch and the bladder pressure by way of an air valve in one end of the tank. It's quite a basic system. It seems to run and work exactly as it should apart from constantly drawing massive amounts of power at all times.

Sir Arthur Daley

I would check the air pressure in the vessel itself, it may be low in pressure or the balloon inside of it may be burst.

2011

How many kW is the motor rated at?
This will be written on the name plate on the motor itself.

Bruthal

Is there a properly working RCD on this pump socket circuit?

For a €600 electrical bill increase, it would take a 2kw load for the entire billing period, on 24 hours a day. Or a fairly decent live to earth fault on the circuit.

Bruthal

Sir Arthur Daley wrote: »

I would check the air pressure in the vessel itself, it may be low in pressure or the balloon inside of it may be burst.

Would that cause it? Id be curious about that. With no bladder, pump will come on the instant the taps are turned on with no bladder keeping pressure on the water, and stop almost the instant they are turned off. No buffer with bladder gone.

Wouldnt work great, but probably no major increase in pump run time unless there was/also a leak.

Maybe Im looking wrong.

2011

Bruthal wrote: »

Would that cause it? Id be curious about that. With no bladder, pump will come on the instant the taps are turned on with no bladder keeping pressure on the water, and stop almost the instant they are turned off. No buffer with bladder gone.

Yes, the pump would just have shorter and more frequent duty cycles.
However the running time would be practically identical as would the power consumption.

budgetbuilder

Bruthal wrote: »

Is there a properly working RCD on this pump socket circuit?

For a €600 electrical bill increase, it would take a 2kw load for the entire billing period, on 24 hours a day. Or a fairly decent live to earth fault on the circuit.

There is an rcd on the main fuseboard that seems to be working. Although, the mcb's usually cut out first if there's a fault. The pump is a 3/4 kw. It's plugged into a double socket via an extension cable and there is a fridge freezer plugged into the other socket. The plug going to the pump has been fitted with a remote control and while that is switched off the bill has gone down even though the f/f has been running constantly from that socket. I tested the plug with the back off to see if there was a leak from the live to the earth or neutral and while the live was "live" the others were fine. I have an electrician coming around this afternoon to have a look and hopefully he'll be able to figure out what the problem is. If not I'll have to bite the bullet and move forward my plans for a new well and pump. Something I was hoping to be able to put off for another couple of years...

frankmul

Get a energy monitor, plug in or clip on. Some of the clip unit now record historical data so you could see when it is using the power

2011

budgetbuilder wrote: »

There is an rcd on the main fuseboard that seems to be working. Although, the mcb's usually cut out first if there's a fault. The pump is a 3/4 kw.

I doubt that the motor that large.

A 4kW load will draw at least 17.39 amps.
A 4kW load with a power factor of 0.9 (typical motor power factor) will draw 19.3 amps.

Remember a normal BS 1363 plug top is fused at a maximum of 13A.

Have a look at the name plate on the motor. This will provide you with the full load current and kW rating.

It's plugged into a double socket via an extension cable and there is a fridge freezer plugged into the other socket.

Not an ideal arrangement.

The plug going to the pump has been fitted with a remote control and while that is switched off the bill has gone down even though the f/f has been running constantly from that socket.

I would find it hard to believe that the pump alone is responsible for any more than a small percentage of your bill.

I tested the plug with the back off to see if there was a leak from the live to the earth or neutral and while the live was "live" the others were fine.

What test method did you use & what test equipment?

I have an electrician coming around this afternoon to have a look and hopefully he'll be able to figure out what the problem is.

Good idea.

If not I'll have to bite the bullet and move forward my plans for a new well and pump. Something I was hoping to be able to put off for another couple of years...

I doubt this will be necessary.

2011

For small money you could install a power meter on the pump itself. This would allow you to see exactly what the pump is costing you to run.

I bought reconditioned ESB meters in the past for €35 (about 8 years ago).

Zen65

2011 wrote: »

I doubt that the motor that large.

A 4kW load will draw at least 17.39 amps.
A 4kW load with a power factor of 0.9 (typical motor power factor) will draw 19.3 amps.

Remember a normal BS 1363 plug top is fused at a maximum of 13A.

I thought he meant 3/4Kw = 0.75Kw? (hard to find ¾ on your keyboard)

2011

Zen65 wrote: »

I thought he meant 3/4Kw = 0.75Kw? (hard to find ¾ on your keyboard)

Apologies, I read that as 3 to 4 kW.
Yes 750 watts is correct.

This bring up another interesting point. The pump will use 0.75 units of electricity per hour of use which costs approximately €0.15 per hour (inc. VAT).

So even if the pump somehow ran non stop for the entire 2 month billing period the cost would be little over €200.

BarryD

2011 wrote: »

So even if the pump somehow ran non stop for the entire 2 month billing period the cost would be little over €200.

I was kinda thinking when I read this that maybe he was pumping water unknowingly for several neighbours as well! Given Irish Water etc. But this couldn't be the case if it's a 0.75Kw power consumption.

I'd be guessing that there was some other change in household habits at same time? Maybe the immersion heater was switched on more often than he thinks or something like that? Electric room heaters?

Bruthal

budgetbuilder wrote: »

I tested the plug with the back off to see if there was a leak from the live to the earth or neutral and while the live was "live" the others were fine.

It would be interesting to know what you expected to see in those tests, and indeed how you did them. Phase tester?

The earth will stay more or less at 0v even if there is a live to earth leak, assuming a proper earth.

And a properly working RCD on the circuit would trip at a leakage of 0.03 amps or above. Where as your €600 bill increase would require around 9 amps leakage to earth for the entire bill, that`s 300 times the level that the RCD would trip at.

So slightly possibly either an earth fault on the pump/pump circuit with the RCD not tripping, or something else powered from that circuit that you are forgetting about.

BarryD

Well, what's the story? I'm mildly interested as we have a well & pump here..

budgetbuilder

BarryD wrote: »

Well, what's the story? I'm mildly interested as we have a well & pump here..

Well, I had an electrician come out and test everything. he found that there was a slight fluctuation in the voltage but nothing to raise suspicion and certainly nothing to account for the horrendous bills. His best guess is that there was something wrong with the meter (a black plastic thing out of the ark) and when the esb guy came to "test" it he really fixed the problem, (most likely that something, perhaps the fuse, was arcing) laid the blame a the feet of the pump to divert suspicion away from the meter so that they wouldn't have to pay back the several thousand euro in overcharging that had happened. having kept track of meter readings every 24 hours for the last few days with the pump plugged in all the time, I have to say, the house isn't using much more power, about 15 units per day,than it was with it on the remote control which was averaging in at about 11 -13 units per day.

2011

budgetbuilder wrote: »

His best guess is that there was something wrong with the meter (a black plastic thing out of the ark)

Very unlikely. These meters are very robust. The newer meters are more troublesome.

when the esb guy came to "test" it he really fixed the problem, (most likely that something, perhaps the fuse, was arcing)

There is no fault that can occur with a fuse that could cause this.
I can't see how voltage fluctuations could cause the meter to over estimate.

laid the blame a the feet of the pump to divert suspicion away from the meter so that they wouldn't have to pay back the several thousand euro in overcharging that had happened.

I would be surprised. Any money due back would not be his problem.

Bruthal

2011 wrote: »

There is no fault that can occur with a fuse that could cause this.

No. Sounds like wild guessing from a layman there.

I can't see how voltage fluctuations could cause the meter to over estimate.

Me either.

Higher voltage gives higher meter readings alright. But fluctuations will mean nothing to overall readings.

2011

Bruthal wrote: »

Higher voltage gives higher meter readings alright. But fluctuations will mean nothing to overall readings.

If the voltage ever went to levels high enough cause a €700 bill (that is €600 more than normal according to the OP) there would be nothing left of the pump

Bruthal

2011 wrote: »

If the voltage ever went to levels high enough cause a €700 bill (that is €600 more than normal according to the OP) there would be nothing left of the pump

It would only take around 600 volts for the bill duration. That's not too bad a fluctuation

2011

Bruthal wrote: »

It would only take around 600 volts for the bill duration. That's not too bad a fluctuation

I tell ye I have seen a few fluctuations in my day, but that would have to be the mother of all fluctuations

Zen65

Bruthal wrote: »

It would only take around 600 volts for the bill duration. That's not too bad a fluctuation

That's just about the most absurd suggestion I've heard. You think the house was receiving more than double the voltage and it wasn't noticed? What about all the bulbs blowing, and the fridge being on fire?

2011

Zen65 wrote: »

That's just about the most absurd suggestion I've heard. You think the house was receiving more than double the voltage and it wasn't noticed? What about all the bulbs blowing, and the fridge being on fire?

I am very confident that he was being sarcastic.
Bruthal worked for the ESB.

Bruthal

Zen65 wrote: »

That's just about the most absurd suggestion I've heard.

Someone taking it serious seems somewhat surprising.

Bruthal

2011 wrote: »

I am very confident that he was being sarcastic.

BarryD

Hmm.. I'd still be guessing that there was some other change in household habits at same time? Heard of a local around here who had a huge bill and nobody could 'explain' it until it transpired that the hot water immersion was used a lot more than normal and some people in the house had fan heaters going for hours etc. Oh dear, says the person - we didn't think of that!! Off to the community welfare officer then to get help with the bill..

2011

BarryD wrote: »

Hmm.. I'd still be guessing that there was some other change in household habits at same time? Heard of a local around here who had a huge bill and nobody could 'explain' it until it transpired that the hot water immersion was used a lot more than normal and some people in the house had fan heaters going for hours etc. Oh dear, says the person - we didn't think of that!! Off to the community welfare officer then to get help with the bill..

Agreed, hence my suggestion in post #13

A friendly neighbor my have tapped into the supply, it would not be the first time this has happened.