water pump: next to house OR tank?

[Rookiescot]

Oh and a word of caution. 

I replaced the pump at my house and failed to gag back the manual valve on the bum gun in the toilet.

I swear you could have cut steel with that jet flow.

[Rookiescot]

4 minutes ago, sandyf said:

If the supply is restricted then that has been the problem all along and would need addressing wherever the pump.

if the pump is near the house he would soon be aware if there was cavitation.

 

Placing the pump as close to the supply as possible minimises the potential for restrictions.

As I said earlier a pump can overcome partial restrictions on its outlet but not its inlet. 

[sandyf]

5 minutes ago, STD Warehouse said:

seems like theres no common consensus here. some say by the tank, some say by the house.

 

I guess if next to the house,  the pump is being forced to "suck" water from a source 120m away, which seems wrong and they are called pumps not sucks., my 2 cents

The pump is not being forced to suck anything, With the pump at ground level the water pressure at the inlet will be a lot higher than you see at the outlets. You have a gravity feed and your water pressure gets reduced by the reducing size of pipe to the outlets and then again by the height your taps and shower heads are above ground level.

[sandyf]

2 minutes ago, Rookiescot said:

 

Placing the pump as close to the supply as possible minimises the potential for restrictions.

As I said earlier a pump can overcome partial restrictions on its outlet but not its inlet. 

You seem to think there is no existing water pressure at the house.

[WhiteBuffaloATM]

many expert but necessarily incomplete technical solutions here , without site survey......

no mention of filters, control panel......

surely his entire (poorly designed) system needs to be reviewed / respecified / replaced,

following site survey by expert pump engineer or,if budget problems, then altered /improved  ?

[Rookiescot]

9 minutes ago, sandyf said:

You seem to think there is no existing water pressure at the house.

 

Where did I suggest that?

By placing the pump as close to the supply tank as he can he will maximise the benefit from the head pressure (the tank is 4 meters above the ground?) to supply the pump.

[Artisi]

8 minutes ago, STD Warehouse said:

seems like theres no common consensus here. some say by the tank, some say by the house.

 

I guess if next to the house,  the pump is being forced to "suck" water from a source 120m away, which seems wrong and they are called pumps not sucks., my 2 cents

The only time a pump "sucks" is then it's not working as it should - - - as in this bloody pump "sucks" it's useless ????

 

Flow to a pump is the result of atmospheric pressure + static height of the supply source above the pump inlet minus the friction and enter losses in the pipe work. 

 

In theory a pump can be positioned miles from the source provided the losses to the pump are within the pump inlet parameters.

 

Guess you are now completely confused by some of the conflicting and contradictory info. 

 

What you have is a very simple hydraulic exercise  to undertake. 

 

Here's my suggestion, buy a 1000 or  2000 litre tank, install it at the house, connect the tank at the well to it -that will keep it filled, the float control valve in the house tank will stop it overflowing - install a pump on the house tank to supply all your needs. 

Job done, a simple exercise to solve your needs. 

[Rookiescot]

7 minutes ago, Artisi said:

The only time a pump "sucks" is then it's not working as it should - - - as in this bloody pump "sucks" it's useless ????

 

Flow to a pump is the result of atmospheric pressure + static height of the supply source above the pump inlet minus the friction and enter losses in the pipe work. 

 

In theory a pump can be positioned miles from the source provided the losses to the pump are within the pump inlet parameters.

 

Guess you are now completely confused by some of the conflicting and contradictory info. 

 

What you have is a very simple hydraulic exercise  to undertake. 

 

Here's my suggestion, buy a 1000 or  2000 litre tank, install it at the house, connect the tank at the well to it -that will keep it filled, the float control valve in the house tank will stop it overflowing - install a pump on the house tank to supply all your needs. 

Job done, a simple exercise to solve your needs. 

 

He already has a head tank.

His question was where to fit the supply pump.

[tifino]

one assumes OP is wanting an Auto pressure type pump? - for the pump to auto detect whenever a Demand is triggered by a Tap being Opened at the House...

 

  If the Pump is placed at the house; wouldn't there be problems with the auto detection system being affected? (as in over active) - in that the possible random cavitation effect would make the 'auto' assume the tank was getting too low to allow the pump to continue... 

 - hence the possibility of a very annoying stop start stop start stop...  much the same as like  how an aircon compressor overcycles when the conditions are not right...

[bankruatsteve]

Lot's of opinions to consider - doubt if there is only 1 answer though.  Before you decide, I suggest you check out the tank for debris at the bottom.  Get a union and cut the PVC at the tank (if you don't already have a flush valve).  Check the output.  Give a flush to the 120 meter of pipe to make sure no built up residue inside that.

I doubt it really matters whether the pump is at the tank or the house.  Personally, I don't really like having equipment so far away.

[Cake Monster]

1 hour ago, STD Warehouse said:

seems like theres no common consensus here. some say by the tank, some say by the house.

 

I guess if next to the house,  the pump is being forced to "suck" water from a source 120m away, which seems wrong and they are called pumps not sucks., my 2 cents

Most of the pumps on sale will " push " the Water and will not " suck ' the water.

They act more as an accelerator than an actual proper pump that draws water and pushes it.

Put the pump close to your Tank, and install an inline filter of some kind to prevent any crud being sent down the pipe into the House,

[Rookiescot]

9 minutes ago, tifino said:

one assumes OP is wanting an Auto pressure type pump? - for the pump to auto detect whenever a Demand is triggered by a Tap being Opened at the House...

 

  If the Pump is placed at the house; wouldn't there be problems with the auto detection system being affected? (as in over active) - in that the possible random cavitation effect would make the 'auto' assume the tank was getting too low to allow the pump to continue... 

 - hence the possibility of a very annoying stop start stop start stop...  much the same as like  how an aircon compressor overcycles when the conditions are not right...

 

Some industrial pumps do have dry running protection (used depending on the process and chemicals involved) but domestic "auto" pumps have the pressure switch on the discharge side of the pump so it can see demand.

 

[bankruatsteve]

4 minutes ago, Cake Monster said:

Most of the pumps on sale will " push " the Water and will not " suck ' the water.

I'm pretty sure most pumps will suck although the head spec is mostly for the push.

[Artisi]

24 minutes ago, Rookiescot said:

 

He already has a head tank.

His question was where to fit the supply pump.

Fully aware of that fact.

It was offered as a workable system without all the - this is better, that is better

A house tank overcomes the pump losses either pumping from the o/ head tank  or losses on the inlet side if installed at the house, a pump at the house ensure full flow and pressure - at the house. 

[Rookiescot]

5 minutes ago, Artisi said:

Fully aware of that fact.

It was offered as a workable system without all the - this is better, that is better

A house tank overcomes the pump losses either pumping from the o/ head tank  or losses on the inlet side if installed at the house, a pump at the house ensure full flow and pressure - at the house. 

Sorry mate if I came across as arrogant or something then I apologise. It was not intentional.

If he fits a new head tank at the house will he not be faced then with an issue of how to get the water from source to head tank?

[Artisi]

4 minutes ago, Rookiescot said:

Sorry mate if I came across as arrogant or something then I apologise. It was not intentional.

If he fits a new head tank at the house will he not be faced then with an issue of how to get the water from source to head tank?

????????

Not a head tank at the house, a ground mounted tank fed by gravity flow from the original supply tank, a 2000 litre house tank would give heaps of storage and it wouldn't matter how slow it is  to fill as it is being constantly being supplied by other tank even when no house demand

[Rookiescot]

7 minutes ago, Artisi said:

????????

Not a head tank at the house, a ground mounted tank fed by gravity flow from the original supply tank, a 2000 litre house tank would give heaps of storage and it wouldn't matter how slow it is  to fill as it is being constantly being supplied by other tank even when no house demand

Ah with you now.

Yes that would resolve the issue but would include extra costs. It might well be worth doing dependent on the OP's circumstances.

[VocalNeal]

1 hour ago, STD Warehouse said:

I guess if next to the house,  the pump is being forced to "suck" water from a source 120m away, which seems wrong and they are called pumps not sucks., my 2 cents

 

In the case of Mitsubishi they are designed to pull up from a well. Hence the 9m suction.

You say 4m but is that to the top of bottom of the tank. Doesn't matter as the pump will pull from either. We also have to figure in the atmospheric pressure on top of the liquid in the tank. Any pump with a 300W rating will do for you. (7 taps) All open at the same time?

Yes Mitsubishi pump's tanks do seem to pinhole corrode after many years but they are only about 1800 Baht to replace. Or you can get a stainless tank from the outset. About 3000 baht.

2 hours ago, Rookiescot said:

OK I had a think about this and after over 20 years of working in chemical factories with storages and delivery pumps I cannot recall a single one which had the pump at the end of the line.

Every one had the pump located as close as possible to the supply tank bottom outlet.

Has to be a reason for that.

 

In those cases the process engineer did all the calculations needed to ensure the pump fitted the application. I'm sure that plant probably had pumps that lifted from below ground and the like.

I have too many years of sizing and selecting control valves for the paper industry. So was very interested in the pressure available at the inlet of said valves. 

Edited May 22, 2021 by VocalNeal

[Rookiescot]

13 minutes ago, VocalNeal said:

 

In the case of Mitsubishi they are designed to pull up from a well. Hence the 9m suction.

You say 4m but is that to the top of bottom of the tank. Doesn't matter as the pump will pull from either. We also have to figure in the atmospheric pressure on top of the liquid in the tank. Any pump with a 300W rating will do for you. (7 taps)

Yes Mitsubishi pump's tanks do seem to pinhole corrode after many years but they are only about 1800 Baht to replace. Or you can get a stainless tank from the outset. About 3000 baht.

 

In those cases the process engineer did all the calculations needed to ensure the pump fitted the application. I'm sure that plant probably had pumps that lifted from below ground and the like.

I have too many years of sizing and selecting control valves for the paper industry. So was very interested in the pressure available at the inlet of said valves. 

 

My experience is that centrifugal pumps are never good at "lifting" and usually need primed first.

Positive displacement pumps on the other hand cause a vacuum and will lift no problem.

 

Process engineers engage in black arts. Thing is though. Every time I raised a temporary Mod to drain a line or pump when I asked what size of restrictor plate do I need to put in the line to drain it the answer was always the same.

7 mm ???? .

Edited May 22, 2021 by Rookiescot
typo

[VocalNeal]

3 hours ago, Rookiescot said:

My experience is that centrifugal pumps are never good at "lifting" and usually need primed first.

 

Correct. One of the reasons the local pumps have an integral check valve. In the OP's cars we have positive pressure when stopped. So the system will be full.  

 

 

[soi3eddie]

Put the pump by the tank as there is already power there. It will avoid noise bothering you too. A decent pump will give good pressure and advise going for a good contant pressure square pump (as they don't pulse). Here's what I did abour 18 months ago in Buriram. Sited about 20 metres from the house and slightly below the house level. Very good pressure and flow. The black pump is from the borehole. The yellow pump supplies the house. The concrete cylinders simply used to rais them off the ground in case of rain.

 

Edited May 22, 2021 by soi3eddie

[KeeTua]

5 hours ago, Artisi said:

Here's my suggestion, buy a 1000 or  2000 litre tank, install it at the house, connect the tank at the well to it -that will keep it filled, the float control valve in the house tank will stop it overflowing - install a pump on the house tank to supply all your needs. 

Job done, a simple exercise to solve your needs. 

That's a good solution if there is a good spot for the extra tank at the house. And add a check valve or two and/or gate valves so there will still be gravity flow from the original tank when the power goes out.

[sandyf]

17 hours ago, Cake Monster said:

Most of the pumps on sale will " push " the Water and will not " suck ' the water.

That is completely wrong. The most common form of on demand water pump used here is designed to "suck" water. They are often referred to as shallow well pumps for use up to 5 metres down.

I have 2 of those , one used for sucking and one used for pushing. I also have a deep well pump of similar construction but some of the output is pushed own the well to help bring water up, that can suck from about 30 metres down.

[Ralf001]

19 hours ago, STD Warehouse said:

Tank been there for 30 years, back when there was not really electricity in this area, so they raised it to get a semi decent flow to the old bungalows that were previously here

 

Is the house plumbing 30years old as well ?

 

Its never fun to dig up the loungeroom floor chasing water leaks from old busted plumbing !!

 

[BritManToo]

16 minutes ago, Ralf001 said:

Is the house plumbing 30years old as well ?

Its never fun to dig up the loungeroom floor chasing water leaks from old busted plumbing !!

Why would you dig up the lounge floor?

Normally anything with running water is on an outside wall.

[sandyf]

18 hours ago, Rookiescot said:

 

Where did I suggest that?

By placing the pump as close to the supply tank as he can he will maximise the benefit from the head pressure (the tank is 4 meters above the ground?) to supply the pump.

The water pressure from the tank will be the same anywhere along the supply line.

You should give over with the scaremongering, and more consideration given to reality. Cavitation is an extremely unlikely event in a domestic water pump scenario. It is effectively caused by bubbles in the flow normally created by something in the water that has overheated and evaporated, such as a cooling agent. Completely different to getting air in the pump.

I have 3 of these pumps and look after 2 others. My Mitsy sucks the water out of an underground septic tank onto the garden. I do that for about 15 minutes every day. Quite often I forget to switch it off and it empties the tank and starts sucking air, quite often the pump overheats and the thermal trip cuts out. Been doing that a couple of times a month for the last 12 years without a problem.

Towards the end of every dry season as the well level gets close to the valve the pump starts to suck air, you have to wait for the well to replenish, bleed the pump and start again. Happens several times every year and has done so for the last 9 years without a problem.

When the pump starts to suck air you get a few large bubbles, not millions of small ones, and the pump stops pumping, there is no cavitation.

The problem is for the OP to make his own mind up and do what he considers best.

[Ralf001]

6 minutes ago, BritManToo said:

Why would you dig up the lounge floor?

Normally anything with running water is on an outside wall.

 

 

Happened in a previous house I rented, pipes were under the floor of the house.

 

House Iam currently renting has an internal kitchen (no external walls)....I expect the plumbing for that also comes under one of the floors too.

 

[crazykopite]

First thing you need is a good pump most of the ones sold in Thailand are rubbish and are always troublesome mine is German made the price has come down considerably since I purchase it at home pro the furthest tap from the pump is 70 metre and I can tell you the power of the water is amazing so I’m sure it would suit your problem it’s also super quiet personally I would have it by the tank here are a few pics of the pump I’ve had this for a good 3 years+ never ever an issue it’s completely weather proof I thing I paid 9,000 but as I said tge price has come down a lot and it’s a brilliant pump it even has a pressure gauge within the housing .

[Andrew Dwyer]

18 minutes ago, BritManToo said:

Why would you dig up the lounge floor?

Normally anything with running water is on an outside wall.

From what I see of new house builds the pvc is always laid under the house slab , poorly assembled and use of glue is optional.

2 years after moving into a new house it developed a water leak underneath the house. After some serious investigation I found the leak was somewhere under the house and had no option other than running all new pvc externally .

[AlfHuy]

20 hours ago, Rookiescot said:

All pumps make a noise when they are running.

If you have a pump that makes no noise then its broken.

Oh dear.

I thought I was healthy.

My heart pumps blood and I can't hear a thing.