Pvc pipe sizes for pump system.

[Wongkitlo]

I want to modify a pump system from pumping from a tank directly to several rooms, to a system where  I pump  from the tank to another storage tank which is on a high stand uphill and from there gravity feed back down to the rooms. I was going to install a cock and ball system on the high stand tank so it shuts off the pump when full. I have the most powerful hitachi pump from Siam Global.

At present the outlet from the pump converts from 2 inch (or 1.5 inch-sorry not sure exact size) pvc pipe to a half inch(smallest size pvc pipe). At present he high stand tank has the larger size pvc for its input. I want to adapt the old system so it goes from the 2 inch to the half inch and when it reaches the high tank it goes back to the 2 inch pipe. The distance between the 2 tanks  is about 100 metres so it will save me a lot of pipe by adapting the old system instead of laying new 2 inch pipe all the length. 

I was hoping some kind people would know if I will have trouble maintaining pressure when it goes from 1/2 inch back to 2 inch. I was thinking because it is a sealed system It should be ok. Thank you.

[sometimewoodworker]

You are making a common mistake, you are introducing large friction losses for no benefit apart from piping costs. Feeding through a ½ will use more power, wear out the pump faster, reduce the litres per minute drastically, so is in general a bad idea. 
 

To get the best performance you should run the pipe with the same diameter pipe as the outlet from the pump.

 

From the tank you should run the largest sensible pipe size. The importance of the tank to the rooms is not the distance, if you are using at least 2” pipe, but the hight from about midway in the tank to the outlets. If you are 10 meters from those 2 points you will get 1 bar of pressure, this is a very low pressure system. For each 10 meters hight you gain 1 bar of pressure. You need about 25 meters to equal the pressure of most pumps, to equal our pump you need 55 meters hight.

 

So can you run ½ pipe from the pump? Absolutely. It’s a bad idea.

Can you run ½ pipe from the tank? Yes you can but it’s a terribly bad idea and your flow is going to match a geriatric snail.
 

For what it’s worth you do not have anything resembling a sealed system.

Edited November 10, 2022 by sometimewoodworker

[tweedledee2]

I am not an expert on flow rates and pump pressures required for your project. But I doubt your pump is capable of pushing water 100 meters and then up to an elevated tank. Most Hitachi and compatible style pumps are designed to pump water a certain distance horizontally or vertically but definitely not at the same time.

[OneMoreFarang]

1 hour ago, Wongkitlo said:

I was hoping some kind people would know if I will have trouble maintaining pressure when it goes from 1/2 inch back to 2 inch.

Obviously you will lose a lot of pressure. Isn't that obvious?

 

If the pump has 2" output, then just use 2" pipe - all the way.

[sometimewoodworker]

3 minutes ago, tweedledee2 said:

I am not an expert on flow rates and pump pressures required for your project. But I doubt your pump is capable of pushing water 100 meters and then up to an elevated tank. Most Hitachi and compatible style pumps are designed to pump water a certain distance horizontally or vertically but definitely not at the same time.

The distance is only relevant if you are using small bore pipe, then you are going to get friction losses. Use at least a 2” pipe and as long as the head is not over about 20 metres and it should be OK

[Wongkitlo]

9 minutes ago, tweedledee2 said:

I am not an expert on flow rates and pump pressures required for your project. But I doubt your pump is capable of pushing water 100 meters and then up to an elevated tank. Most Hitachi and compatible style pumps are designed to pump water a certain distance horizontally or vertically but definitely not at the same time.

Thanks for your input. At present the high tank is being used to store water from a well. I am pretty sure the pump is very old but seems to have no trouble filling from there but following your advice I will check it out. 

[Wongkitlo]

10 minutes ago, OneMoreFarang said:

Obviously you will lose a lot of pressure. Isn't that obvious?

 

If the pump has 2" output, then just use 2" pipe - all the way.

I hated physics at school so is not obvious but thank you for your advice. 

[sometimewoodworker]

4 minutes ago, OneMoreFarang said:

Obviously you will lose a lot of pressure. Isn't that obvious?

Regrettably to most people it is far from obvious until they have empirical evidence.

 

SWMBO used a ¾” 100 metre pipe to water her plants, she complained bitterly when I bought a 1 ½” x 100 metre pipe saying it was a waste of money. Then she found it took a much shorter time to do the same job.

 

So obvious? Only if you actually paid attention in physics classes and actually remember them.

[Wongkitlo]

12 minutes ago, sometimewoodworker said:

The distance is only relevant if you are using small bore pipe, then you are going to get friction losses. Use at least a 2” pipe and as long as the head is not over about 20 metres and it should be OK

Thank you and everyone from saving me from a big mistake. I will get the thicker pipe. 

[OneMoreFarang]

Why does this work?

And what would be the opposite?

Even without paying much attention in school most of us learned that when we were kids.

 

 

[Wongkitlo]

9 minutes ago, sometimewoodworker said:

Regrettably to most people it is far from obvious until they have empirical evidence.

 

SWMBO used a ¾” 100 metre pipe to water her plants, she complained bitterly when I bought a 1 ½” x 100 metre pipe saying it was a waste of money. Then she found it took a much shorter time to do the same job.

 

So obvious? Only if you actually paid attention in physics classes and actually remember them.

Thanks. I am lucky I have you guys who did pay attention. ????

[farmerjo]

2 hours ago, Wongkitlo said:

I want to modify a pump system from pumping from a tank directly to several rooms, to a system where  I pump  from the tank to another storage tank which is on a high stand uphill and from there gravity feed back down to the rooms

Can i ask why you would want to do that.

[sometimewoodworker]

1 hour ago, OneMoreFarang said:

Why does this work?

And what would be the opposite?

Even without paying much attention in school most of us learned that when we were kids.

For those who understand the actual principles most of physics is self evident. However the vast majority find it a black art specially when restricting the flow makes the water go farther.

 

If you really want to blow even intelligent minds try getting into thermodynamics and the science of radiation barriers and the differences between reflective and radiant barriers specially when the same material can be both dependent on placement and orientation. 

[Wongkitlo]

58 minutes ago, farmerjo said:

Can i ask why you would want to do that.

 

58 minutes ago, farmerjo said:

Can i ask why you would want to do that.

It is a 9 room guesthouse. I had tanks feeding the rooms by gravity but was not enough pressure. I installed the pump and ever since have had trouble with too much pressure. A toilet doesnt close properly after flushing, a pipe breaks etc and the pump will run continually till I find the problem. I have had 3 or 4 incidents in the last week. I have just taken over the property next door and they are up the hill and  have the tower in the picture. I thought of pumping from the first property up the hill and up to the tower and then gravity feeding back. I thought then if I had a breakage it would not really affect the pump and I could just fix it in the morning instead of running around knocking on doors at night asking if the toilet is running. Thank you for your interest. 

[Wongkitlo]

1 hour ago, farmerjo said:

Can i ask why you would want to do that.

The purple roof is the roof of the original guesthouse. I am standing at the same level as the base of the tower. I think it will be enough height for gravity feed.

[farmerjo]

13 minutes ago, Wongkitlo said:

 

It is a 9 room guesthouse. I had tanks feeding the rooms by gravity but was not enough pressure. I installed the pump and ever since have had trouble with too much pressure. A toilet doesnt close properly after flushing, a pipe breaks etc and the pump will run continually till I find the problem. I have had 3 or 4 incidents in the last week. I have just taken over the property next door and they are up the hill and  have the tower in the picture. I thought of pumping from the first property up the hill and up to the tower and then gravity feeding back. I thought then if I had a breakage it would not really affect the pump and I could just fix it in the morning instead of running around knocking on doors at night asking if the toilet is running. Thank you for your interest. 

I would be looking at the pump specs.

If you have instant hot water it won't work well with gravity.

 

[Wongkitlo]

10 minutes ago, farmerjo said:

I would be looking at the pump specs.

If you have instant hot water it won't work well with gravity.

 

It works ok in the top guesthouse and has good pressure.The original one is quite a but lower so I think it will be enough water to work them but will double check. Thank you.

[farmerjo]

I see where your coming from.

I have two houses next to each other but rather than mess with the pressure settings on the pump if showering we all know to turn on another tap so the pump runs continuasly rather than cut in and out.

A lot more difficult to explain when visitors stay.

[Artisi]

If you want to do it properly, engineer it properly - at the moment your running around in circles without any chance of ending up with a successful outcome. 

For starters, you say  toilet/s don't close off properly, you are bursting pipes etc - fix these issues first before worrying about changing the supply method. 

 

Pumping from a tank directly into you system is the best way to go, it just requires to be done correctly with a no leaking toilets, / taps with the pump discharge pressure controlled to suit the pipework etc. 

 

What model Hitachi pump do you have? 

 

[sometimewoodworker]

2 hours ago, Artisi said:

Pumping from a tank directly into you system is the best way to go, it just requires to be done correctly with a no leaking toilets, / taps with the pump discharge pressure controlled to suit the pipework etc. 

that is a rather misleading statement, it needs quite a bit of clarification and even then is probably not true for many people in Thailand.

 

Some of the problems that it won’t fix include significant power cuts, this is not unusual we get short ones at least weekly and ones lasting hours monthly. Those along with water cuts are not uncommon.

 

So the answer for us is to have a pumped pressure system with high level feeder tank for  gravity supply when the power is out.

 

For @Wongkitlo the gravity fed system may well be ideal, however the tiny pipes have got to go to get reasonable flow along with the pressure the hight will give.

9 hours ago, farmerjo said:

If you have instant hot water it won't work well with gravity.

That is false. Virtually all water supplies in Thailand use gravity fed water. The thing is that the water supply towers are high enough to provide sufficient pressure.
 

Is this familiar?

.

So if you have enough hight, 20 metres will be OK, then a gravity feed will be fine if you engineer the pipes correctly.

8 hours ago, Wongkitlo said:

The original one is quite a but lower so I think it will be enough water to work them

Correct the pipe work and it will be good.

 

we have a gravity feed when the power is cut, the way we get that is that all pipes are 1 ½” with just the last few millimetres being ½” to the outlets. We didn’t put our immediate use tank high enough to provide instant water heater pressure because when it is using gravity feed the power is cut so there is no point.

 

for you cutting the power to the pump at night May we’ll be enough.

Edited November 11, 2022 by sometimewoodworker

[farmerjo]

1 hour ago, sometimewoodworker said:

So if you have enough hight, 20 metres will be OK, then a gravity feed will be fine if you engineer the pipes correctly.

Once again it comes back to the engineering or trial and error in the OP's case.

I would like a dollar for every household in our closest village that runs off one of those towers and had instant hot water systems installed that don't work.

To be followed by a tank stand and tank installed that doesn't work  then finally a pressure pump to make it work.

 

We pump from a bore to a tank with a pressure pump,doesn't take long for a bit of sediment to alter the performance of the the instant hot water and it will be the same with gravity.

I guess you could take the filter screen out of the hot water system and have bigger holes in the shower head..

 

 

 

[Wongkitlo]

46 minutes ago, farmerjo said:

Once again it comes back to the engineering or trial and error in the OP's case.

I would like a dollar for every household in our closest village that runs off one of those towers and had instant hot water systems installed that don't work.

To be followed by a tank stand and tank installed that doesn't work  then finally a pressure pump to make it work.

 

We pump from a bore to a tank with a pressure pump,doesn't take long for a bit of sediment to alter the performance of the the instant hot water and it will be the same with gravity.

I guess you could take the filter screen out of the hot water system and have bigger holes in the shower head..

 

 

 

In reality it is a budget hotel and I am happy for the water pressure to not be great. It is on a remote island and the water supply is irregular. I have had guests telling me I have the best showers they have found in Thailand and I walk past and hear their showers running continually. It is not great for my water bills and the already strained water supply. Folliwing your advice I will do some testing on the hot water systems at the new place which is  gravity fed. They have been operating for years before I took over and have not heard of any problems from the previous owners. 

[VocalNeal]

As for the 1/2" pipe feeding the water tank. Don't forget the time factor. The 1/2 will still fill the tank just not as fast. As long as the supply volume over time exceeds the short term discharge volume it will be OK.

[Wongkitlo]

5 hours ago, Artisi said:

If you want to do it properly, engineer it properly - at the moment your running around in circles without any chance of ending up with a successful outcome. 

For starters, you say  toilet/s don't close off properly, you are bursting pipes etc - fix these issues first before worrying about changing the supply method. 

 

Pumping from a tank directly into you system is the best way to go, it just requires to be done correctly with a no leaking toilets, / taps with the pump discharge pressure controlled to suit the pipework etc. 

 

What model Hitachi pump do you have? 

 

I have replaced all the toilet cisterns, countless pipes. It can be as simple as the power cuts out, someone tries a shower and since no power no water, does not turn off properly, they leave for the beach, i have padlocks on tbe doors and many people put on their own padlocks so I can not access the room, the power comes back on and so does the shower and the pump runs continually till they come back and turn off the shower. 

I have basic handyman skills and am reliant on the local Thais and they know better than farungs. I went to buy the pump with a local and took extensive photos to show at the shop. The Thais decided I had to have the largest and most expensive pump. I think it is too strong for the size of the property. The water pressure is full on. I bought a pressure regulator and the Thais decided I did not need it and removed it. I am just a farung and my wife and the locals know better. 

[Wongkitlo]

2 hours ago, sometimewoodworker said:

that is a rather misleading statement, it needs quite a bit of clarification and even then is probably not true for many people in Thailand.

 

Some of the problems that it won’t fix include significant power cuts, this is not unusual we get short ones at least weekly and ones lasting hours monthly. Those along with water cuts are not uncommon.

 

So the answer for us is to have a pumped pressure system with high level feeder tank for  gravity supply when the power is out.

 

For @Wongkitlo the gravity fed system may well be ideal, however the tiny pipes have got to go to get reasonable flow along with the pressure the hight will give.

That is false. Virtually all water supplies in Thailand use gravity fed water. The thing is that the water supply towers are high enough to provide sufficient pressure.
 

Is this familiar?

.

So if you have enough hight, 20 metres will be OK, then a gravity feed will be fine if you engineer the pipes correctly.

Correct the pipe work and it will be good.

 

we have a gravity feed when the power is cut, the way we get that is that all pipes are 1 ½” with just the last few millimetres being ½” to the outlets. We didn’t put our immediate use tank high enough to provide instant water heater pressure because when it is using gravity feed the power is cut so there is no point.

 

for you cutting the power to the pump at night May we’ll be enough.

Thank again you for your advice. You were very helpful when I installed the system and was trying to deal with all the pressure problems

[unheard]

38 minutes ago, Wongkitlo said:

Folliwing your advice I will do some testing on the hot water systems at the new place which is  gravity fed. They have been operating for years before I took over and have not heard of any problems from the previous owners. 

Do you really want to waste your time on trial-n-error and still getting far from the optimum results?

Why not to pay for someone in the business to come in and evaluate the system and offer workable solutions?

There are multiple companies out there doing this very thing.

Getting a conceptual advise over the forum is all fine but the actual engineering can not be done remotely.

Edited November 11, 2022 by unheard

[Wongkitlo]

20 minutes ago, unheard said:

Do you really want to waste your time on trial-n-error and still getting far from the optimum results?

Why not to pay for someone in the business to come in and evaluate the system and offer workable solutions?

There are multiple companies out there doing this very thing.

Getting a conceptual advise over the forum is all fine but the actual engineering can not be done remotely.

Thanks. Such things are difficult  on a remote island. It is an hour by boat from the mainland and on the edge of Cambodia and to get people to come out is far beyond the budget of a cheap guesthouse(especially after being closed 2 years by covid). I was hoping to save money by adapting the old system but have learnt will not work.  Everything here is put together by the locals. Have been waiting for 3 weeks for someone from TOT to come and fix the internet so I am pretty sure getting someone here would be a difficult and expensive exercise.

[Wongkitlo]

48 minutes ago, VocalNeal said:

As for the 1/2" pipe feeding the water tank. Don't forget the time factor. The 1/2 will still fill the tank just not as fast. As long as the supply volume over time exceeds the short term discharge volume it will be OK.

Is interesting what you say because the amount of water I will save by not having it pressurized might compensate for the slow flow with the small pipes. As sometimeswoodworker said it might put excessive strain on the pump which is a consideration. 

[unheard]

46 minutes ago, Wongkitlo said:

Have been waiting for 3 weeks for someone from TOT to come and fix the internet so I am pretty sure getting someone here would be a difficult and expensive exercise.

I used to think that I'm familiar with difficulties associated with remote locations.

But your case is on a completely different scale.

[Wongkitlo]

27 minutes ago, unheard said:

I used to think that I'm familiar with difficulties associated with remote locations.

But your case is on a completely different scale.

Yes it is beautiful. One of the last relatively untouched islands but also a nightmare for logistics. Getting better now we have Lazada