Better control of a water pump

[RogerS]

In the manky cellar is our water treatment plant...



and a simplified diagram



Beneath the pressure vessel is a pump (you can just about see it in this photo)



So water comes in from the borehole - left of diagram - into the drop tanks and there is the pump and pressure vessel that takes water from the drop tanks and pumps it through the iron/manganese filter into the 'clean' water tanks. There is what looks to be a float switch on the 'clean' water tank that is triggered when we draw off clean water up into the house. The float switch seems to be a vertical tube going down in the water and I'm guessing (it's hard to see) that there is some sort of float with a magnet that triggers the switch...no idea what the technical term for such a switch is.

The thing is that this pump seems to keep kicking in throughout the day but doesn't run for very long then there is an audible ker-thump when it switches off. And it's annoying as you can here it in the house. The pressure vessel is supposed to damp this out and as far as I can see (there is a pressure reading on the meter attached to the pump) is pumped up.

So I was thinking about having two level sensors so that I could draw off a reasonable amount of water before the pump kicks in and does a longer refill.

Very much like the heat store control in another thread.

Can anyone see any disadvantages ? Haven't quite got my head round the type of float switch/whatever yet and so any pointers appreciated.

 

[techauthorbob]

Sounds like a good plan to me.

You could also consider flexible insulating mountings for the pump and short flexible pipes either side of the pump to isolate the noise and vibration, this sort of thing is used lots in industry.

Also, what about an insulated box over the pump to cut down external noise?

I am quite jealous of your borehole and the nicer tasting water than the stuff we get out of our taps in West Yorkshire, we have a friend with natural water and theirs is much softer than ours.

Bob

 

[RogerS]

.....
I am quite jealous of your borehole and the nicer tasting water than the stuff we get out of our taps in West Yorkshire, we have a friend with natural water and theirs is much softer than ours.

Bob

And it's (relatively) free ! And if it dries up then there is always the well which can also feed into the treatment plant.

Having posted the OP I see that there are some clever gizmo's that incorporate both in the one float.

I also believe that there is a defect in the system around this pump as I've noticed that it will kick in when we're not drawing off any water from the system. So clearly a pressure leak in the system. I have a call out to the water treatment plant maintenance guys.

 

[AndyP]

Are you obliged to test the bore hole water for contaminates? Do you use it for drinking?

 

[RogerS]

Are you obliged to test the bore hole water for contaminates? Do you use it for drinking?

No...no legal requirement and yes we do use it for drinking as it goes through quite a few filters, iron/manganese extraction and finally a UV light. I can't tell the difference between it and Evian TBH.

I did find that some of the visiting workmen were drinking out of the tap connected to the well (and so untreated and a distinct slight murkiness) but no-one succumbed to any nasties.

 

[AndyP]

Is the water naturally soft?

Our water which is harder than that in London goes through a water filter. I have done many blind tastings. Nobody has yet to tell the difference between the softened an unsoftened water.

 

[RogerS]

Is the water naturally soft?

Our water which is harder than that in London goes through a water filter. I have done many blind tastings. Nobody has yet to tell the difference between the softened an unsoftened water.

I think it must be.

I did get the treated water tested.

 

[AndyP]

Seems that there are a dozen different ways of measuring water hardness. Mine is between 45 and 48 °F (french degrees??) Converts to 180-190 mg/l Ca. Which is why we soften.

 

[TrimTheKing]

Sorry for the hijackRoger, but here's mine from the UU website...

Apparently my water supply come from a reservoir in North Wales, some 76 miles away!!!

The blue dot in the top corner is me.

 

[AndyP]

Clarke is yet another way of measuring water hardness. On the conversion site I am using that is 17.59 mg/l Ca which is very soft

 

[RogerS]

Sorry for the hijackRoger, but here's mine from the UU website...

.....

Ah....soft. Say no more

 

[TrimTheKing]

Sorry for the hijackRoger, but here's mine from the UU website...

.....

Ah....soft. Say no more

:lol: bscene-drinkingcheers:

 

[9fingers]

Back to the original question.
I presume there is yet another pump off diagram to provide water pressure to the taps. If so then I can see no point in a narrow hysteresis float switch as it will cause the rapid on off that you are seeing.

The two switch solution, widely spaced seems the way to go. Depending on your tank material, it is possible that capacitative sensors on the outside of the tank might work and allow infinite adjustment/experimentation. Float switches are cheap enough. Maybe cannibalise ebay/amazon bath level alarms ?

Bob

 

[Rod]

Is the noise water hammer, caused by the sudden stopping of the flow?

Rod

 

[RogerS]

Back to the original question.
I presume there is yet another pump off diagram to provide water pressure to the taps. If so then I can see no point in a narrow hysteresis float switch as it will cause the rapid on off that you are seeing.

Yes there is. It pumps the water via filters various and the UV filter from the clean tanks and into the house.

The two switch solution, widely spaced seems the way to go. Depending on your tank material, it is possible that capacitative sensors on the outside of the tank might work and allow infinite adjustment/experimentation. Float switches are cheap enough. Maybe cannibalise ebay/amazon bath level alarms ?

Bob

Capacitative sensors look like a great idea.

 

[RogerS]

Is the noise water hammer, caused by the sudden stopping of the flow?

Rod

Yes, I think that it is. The pressurised expansion vessel is supposed to dampen it, or so I was told. I must check the pressure on the air side of the diaphragm.

 

[9fingers]

Is the noise water hammer, caused by the sudden stopping of the flow?

Rod

Yes, I think that it is. The pressurised expansion vessel is supposed to dampen it, or so I was told. I must check the pressure on the air side of the diaphragm.

Surprising that the pumps stops so abruptly as to cause water hammer. I'd expect the rotor just to coast to a halt in a second or so? Strange.

Bob

 

[Duncan A]

I would imagine that your pressure vessel should have a water level around 1/2 way up. If the gas (air?, nitrogen?) on top of the water has leaked out, the water level will be too high causing the short cycling that you refer to. Check the water level and top up the gas side if necessary. If you don't have a level indicator, try by feeling the side of the vessel after a decent run or look for condensation to indicate approx level of the cold water.
Duncan

 

[Phil]

What a waste of a very nice wine cellar and tasting room.

Dark wood table, chairs, shelves, small fire place ....................



Sorry Roger, not what you want to hear.

 

[RogerS]

What a waste of a very nice wine cellar and tasting room.

Dark wood table, chairs, shelves, small fire place ....................



Sorry Roger, not what you want to hear.

Ah, that would be the second cellar then

 

[Rod]

Is that a coal Shute and what’s the floor made from?

Rod

 

[RogerS]

No, I don't think it was a coal shute..at least not originally as there is a mullion in the middle.

The floor is concrete (I think) ...I've not looked too closely. The original Georgian drain is there just below the 'window' and still functioning which is just as well as there s a lot of water comes in. One of the previous owners laid a 2" drainage pipe down inside a channel along one side from the water treatment cellar through to this one and then the drain. But over the years, it had got silted up and I've taken it out to at east get some of the water to go away. But when I went down recently even parts of that channel have got silted up....really must go and clean it out.

Long term plan is to tank it.

 

[RogerS]

I need to rename this thread "Why complicate things or as is better known...'How not to be a Numpty'"

I went down to check the pressure in the pressure vessel as prompted by Duncan. Pressure good at 3.5 Bar. So I went back to basics and .... :eusa-doh: that pump is not controlled by any float switch in the clean tanks. Nothing other than it's own differential pressure switch.

The pump is connected to the clean tanks by a long pipe that terminates in a ....

Common-or-garden ballcock

which is leaking

 

[9fingers]

It is that pressure switch that needs a decent hysteresis to stop it going on and off too quickly and yes that pump will stop with a bang as it is working at max pressure just as it switches off.
Although you don't have a huge choice. The lower limit needs to be your minimum desired water pressure and the maximum needs to be a reasonable margin below the maximum rating on the pump. The other parameter you can play with is the volume of the EV(s). Maybe scavenge abandoned calor gas cylinders could be pressed into service but depends if the downstream filtering can cope with the corrosion products. Needs thinking about.

Posh solution could be to run the pump from a 3 phase motor and inverter programmed to slow the pump acceleration and deceleration down to gentle levels. There is always a way of skinning every cat!

Bob

 

[RogerS]

Appreciate the input, Bob.

That pump does not supply the house...merely refills the clean water tanks and so I can do whatever I like pressure-wise.

 

[9fingers]

Appreciate the input, Bob.

That pump does not supply the house...merely refills the clean water tanks and so I can do whatever I like pressure-wise.

So this is a suction pump to lift from bore hole into the tanks then? Not sure why it should be controlled on the basis of pressure now if it all it has to do keep the tanks topped up?

Mystified of Romsey :lol:

 

[RogerS]

Sorry Bob...my bad explanation.

The incoming water comes (pumped) from the borehole by the farm that feeds the four properties. Actually I have no idea where it is...must find out.

It the goes via a filter to remove vegetation etc into the drop tanks. They are in that row on the left. Out of the bottom of those tanks is a pipe that goes to the pump in question. This pump serves two purposes..

1) pumps the water from the drop tank into the iron/manganese filter (the large blue vertical cylinder in the photos) and from there via another filter and then onto the 'bad' ballcock and into the clean tanks.

2) during the night, a few valves open up in that blue iron/manganese filter and the backwash cycle happens which basically takes water from the drop tank and reverse flows it through the iron/manganese filter and churns up all the filtering stuff and flushes out the crud and down the drain. This is powered by that pump.

From the clean tanks, a second pump (which needs replacing - I have a new one plus differential switch on my TUIT list) then pumps water on-demand from the house through more filters, a water softener and UV filter and up into the house.

The pressure on this second pump actually needs increasing by tweaking the differential switch because some of the taps in the house seem a little unhappy (or should I say the overall system seems a little unhappy as there is an imbalance in pressure between cold and hot). This hasn't been an issue with the taps and showers installed to date but the ones I just put into the bathroom seem to 'unsettle' the system and not too happy with the imbalance in pressure. Another TUIT.

I'll replace that ballcock and see how the first pump behaves.

 

[Phil]

Ah, that would be the second cellar then

View attachment 1

{edit- the images got totally pi$$ed}



NOT AS GOOD AS THE OTHER ONE!!!!!


Those steps/stairs - from a safety point of view block them off. Some pi$$ed ass..hole will try them out. :lol: :lol: