Borehole pump serving 2 properties

[Andrew Mackay]

Hi
I have a question relating to a Borehole water pump.

A client has shared access to a borehole. They bought the property 7 years ago and agreed with the sellers that the water supply would be split and be independent of each other (the seller retained a holiday cottage on the site which had a branch pipe from my clients pressure vessel.

Post the sale the seller fitted a pressure vessel and associated pipe work at the well head and it seems to water systems had been established as the original agreement.

Fast forward to last week and my client calls me to say that while the pipe has been separated the borehole pump is powered from the holiday cottage supply. He has asked me if the electrical supply coulsalso be separated so that each pressure vessels pressure switch activates the borehole pump from there own power supply.

The water supply has been powered off twice recently by the seller/holidaycttage owner without warning and understandible my client is not too happy with the present arrangement.

I‘m aware that this might be outside my skills sets but advice would be appreciated even if it is to reassure my client thar
this is possible.

Regards

 

[David Prosser]

Anything can be done question is would you want to put your name to it, you don't even know tht the two properties are on the same supply phase.

Seems an odd idea having one pump for two seperate pressure vessles, what stops it over pressuring one side or does it just rely on PRVs protection each side.

Personally I would try to convice your customer just to move the supply so the pump is fed their house, dependent on how much the holiday home is occupied of course or look at getting twocompletly diffrent systems installed.

 

[Weir Engineer]

Anything can be done question is would you want to put your name to it, you don't even know tht the two properties are on the same supply phase.

Seems an odd idea having one pump for two seperate pressure vessles, what stops it over pressuring one side or does it just rely on PRVs protection each side.

Personally I would try to convice your customer just to move the supply so the pump is fed their house, dependent on how much the holiday home is occupied of course or look at getting twocompletly diffrent systems installed.

My thoughts exactly... swap the pump power supply to the 'permenantly' occupied house as they will use the vast majority of the water. Holiday let will use very little by comparison. Also it'll define ownership of the borehole and subsequent compliance to the Private Water Regulations.

 

[James]

You could use 2 contactors with electrical and mechanical interlocks on them so they cant both be engaged at the same time.
this would prevent the possibility of either back feeding 1 house from the other in the event of them both calling for water at the same time (or indeed a phase to phase short if they are on different phases)

however, the pump in question will be costing around 5 pence per hour in electricity for the time it is running. therefore it is unlikely that either property will get any sort of payback after investment in the equipment and installation.

best guess by the time you have built it, fitted it and run the extra cables from the 2nd property you will be looking at £300 to £500 including parts and labour.
or about 1 year of running 24/7 operation in electrical costs
if it only runs for a couple of hours a day, it will take 12 years to cost £400 in electricity.

 

[Andrew Mackay]

You could use 2 contactors with electrical and mechanical interlocks on them so they cant both be engaged at the same time.
this would prevent the possibility of either back feeding 1 house from the other in the event of them both calling for water at the same time (or indeed a phase to phase short if they are on different phases)

however, the pump in question will be costing around 5 pence per hour in electricity for the time it is running. therefore it is unlikely that either property will get any sort of payback after investment in the equipment and installation.

best guess by the time you have built it, fitted it and run the extra cables from the 2nd property you will be looking at £300 to £500 including parts and labour.
or about 1 year of running 24/7 operation in electrical costs
if it only runs for a couple of hours a day, it will take 12 years to cost £400 in electricity.

The key point is that the client wants an independent system. Is there a manufacturer or control that allows this?

 

[Andrew Mackay]

You could use 2 contactors with electrical and mechanical interlocks on them so they cant both be engaged at the same time.
this would prevent the possibility of either back feeding 1 house from the other in the event of them both calling for water at the same time (or indeed a phase to phase short if they are on different phases)

however, the pump in question will be costing around 5 pence per hour in electricity for the time it is running. therefore it is unlikely that either property will get any sort of payback after investment in the equipment and installation.

best guess by the time you have built it, fitted it and run the extra cables from the 2nd property you will be looking at £300 to £500 including parts and labour.
or about 1 year of running 24/7 operation in electrical costs
if it only runs for a couple of hours a day, it will take 12 years to cost £400 in electricity.

Two cables run from each system into the control box with one output from the control box to the pump. Is the control box the key?

 

[James]

realistically if you want 2 separate systems, don't try to use the same pump for both of them.

it is possible to engineer a bespoke control system that will use power from the house that calls for water first, however by the time you have had someone design and build it, it may turn out to be far more than anyone is willing to pay.

 

[Lucien Nunes]

Yes, the key point here is that there are two electrically independent sources that must be kept strictly separate for safety reasons, which involves a rather more complex engineering task than just making a box that selects one of two sources for functionality. For example, if the supply from one house unexpectedly backfed the other, it could shock and injure an electrician working on a circuit that had been correctly isolated and locked off at its normal supply, which would lead to a minefield of liability concerns.

One simple solution that might get around that would be to run a supply from each house to side-by-side exterior grade sockets at the pumphead. The pump could remain plugged into whichever supply is preferred, but in the event of that supply being turned off, the other is available with five minutes effort to swap the plug over.

I can't see any problem with one pressure switch and two accumulator vessels fed by non-return valves etc. When the pressure in either vessel drops below switch cut-in pressure the pump will start and raise both to normal cut-out pressure.

 

[Zerax]

Thinking holistically about this... I would have thought that a far more sensible solution... is that one party owns and pays for the borehole pump supply and maintenance, with a legal agreement to supply the other party. If the 'owner' is concerned about high usage, then a simple water meter in the supply would allow for monitoring or even charging.

Ideally, this should have been done at the conveyance stage.

 

[DefyG]

Had a somewhat similar situation a few years back where several properties shared 2 Klargester sewage treatment plants from 1 single phase supply. I was asked to carry out an EICR on the landlords installation. It never got started as could not get agreement on price!
There have been arguments since over sharing the bill and ongoing maintenance (mainly as one resident was a single occupant and others were 3/4/5 families, who used the used the facility more than the single!)
It is still ongoing I believe.
Always seems to lead to arguments where facilities are shared!

 

[Lucien Nunes]

Post #10 bot alert, reviving 2 year old thread