Q. How to work out what pressure needed for house water pump?

[sometimewoodworker]

3 minutes ago, Matzzon said:

If the pipes are told old, the only sensible thing is to do a pipe replacement. The safety is there to prevent pipes from bursting. I thought you would understand that as you are so very well versed in construction. However, I was mislead of your previous amount of recommendations. 

Of course if the pipes are too old you need to replace them.  Are you too lacking in intelligence to know that? You have a magic way of knowing when the pipes are degraded enough to burst? I certainly don’t. It could be 4 years, it could be 8 or 12 or more depending on conditions.
 

There is no safety to prevent pipes bursting I thought you could understand that. There is a cut off pressure setting, either fixed or variable, that doesn’t stop pipes bursting.

[Matzzon]

34 minutes ago, sometimewoodworker said:

Of course if the pipes are too old you need to replace them.  Are you too lacking in intelligence to know that? You have a magic way of knowing when the pipes are degraded enough to burst? I certainly don’t. It could be 4 years, it could be 8 or 12 or more depending on conditions.
 

There is no safety to prevent pipes bursting I thought you could understand that. There is a cut off pressure setting, either fixed or variable, that doesn’t stop pipes bursting.

If the pressure is set correctly, the pipes wont burst if they aint to damaged.

[sometimewoodworker]

2 hours ago, Matzzon said:

If the pressure is set correctly, the pipes wont burst if they aint to damaged.

Your English is as good as your knowledge.
 

Blue PVC pipes degrade with U.V. light. Apart from the change in colour, which happens early in the process so does not indicate the extent of the degradation, there is no non destructive way of telling the strength. 
At some point the pipes will become brittle/weak enough that they fail either by over presser from shutting off the tap or from the pump pressure.

 

So while being technical correct in that if the pressure is always set well below the failure point the pipes are unlikely to burst. You are in fact talking out of an orifice not designed for oral communication as you will have to reduce the set point over time with no easy way of discovering how low you have to go and you will get to a point where an anaemic snail will flow faster than your water.

 

I avoid these problems by using PP-R or 13.5 grade pipe the latter kicks the degradation point many years ahead

[Matzzon]

1 hour ago, sometimewoodworker said:

Your English is as good as your knowledge.
 

Blue PVC pipes degrade with U.V. light. Apart from the change in colour, which happens early in the process so does not indicate the extent of the degradation, there is no non destructive way of telling the strength. 
At some point the pipes will become brittle/weak enough that they fail either by over presser from shutting off the tap or from the pump pressure.

 

So while being technical correct in that if the pressure is always set well below the failure point the pipes are unlikely to burst. You are in fact talking out of an orifice not designed for oral communication as you will have to reduce the set point over time with no easy way of discovering how low you have to go and you will get to a point where an anaemic snail will flow faster than your water.

 

I avoid these problems by using PP-R or 13.5 grade pipe the latter kicks the degradation point many years ahead

Congrats! You just said the relining do not exist. oN the other way you do not do that on only pvc pipes. However, Cameras are still available, right?

[The Theory]

It is possible to set the pressure of water to lower or higher by replacing pressure switch. This Hitachi (residential type) pressure switch is available in 3 different types. There is no need to replace the pump if more or less pressure is needed depends on what is in use currently. 
 

Edited September 9, 2020 by The Theory

[sometimewoodworker]

55 minutes ago, Matzzon said:

Congrats! You just said the relining do not exist. oN the other way you do not do that on only pvc pipes. However, Cameras are still available, right?

Would you like to provide an English translation from your post? 

[Matzzon]

8 hours ago, sometimewoodworker said:

Would you like to provide an English translation from your post? 

That´s is probably the answer of a person that suddenly understands that he don´t have a clue in the field I am talking about. Do you know how to check pipes? Are you familiar with the term relining? If not, then Google both instead of shifting to your apparent reading disorder.

[sometimewoodworker]

1 hour ago, Matzzon said:

That´s is probably the answer of a person that suddenly understands that he don´t have a clue in the field I am talking about. Do you know how to check pipes? Are you familiar with the term relining? If not, then Google both instead of shifting to your apparent reading disorder.

I am certainly aware of relining. It’s not something that is ever done in a normal domestic setting in Thailand. 

I am certainly aware of checking pipes. It’s not something that is ever done in a normal domestic setting in Thailand.

 

How about actually talking about normal domestic installations rather than trying to bring in industrial procedures that have absolutely no relevance in this thread.

 

If you could take the time to write English rather then getting so hot under the collar you think that 

12 hours ago, Matzzon said:

You just said the relining do not exist.

Is understandable. and you seem to attribute a statement to me that I didn’t say.

Or this

12 hours ago, Matzzon said:

oN the other way you do not do that on only pvc pipes.

 

[Matzzon]

23 minutes ago, sometimewoodworker said:

I am certainly aware of relining. It’s not something that is ever done in a normal domestic setting in Thailand. 

I am certainly aware of checking pipes. It’s not something that is ever done in a normal domestic setting in Thailand.

 

How about actually talking about normal domestic installations rather than trying to bring in industrial procedures that have absolutely no relevance in this thread.

 

If you could take the time to write English rather then getting so hot under the collar you think that 

Is understandable. and you seem to attribute a statement to me that I didn’t say.

Or this

 

Just continue you BS about a misspelling. if you read, I also said that they do not use relining. What I wanted to suggest with my post was that it´s quite easy to buy a small camera system to check your own pipes for just under 5000 baht. Not really a problem, and then you know if it´s time to changes pipes or not.

 

Now this was about choosing pump. I still say that they have regulators that shut the pump off if it goes over a certain pressure. The only thing you need to know is if your pipes are ok or not. If they are okay, then you just need to read the fact sheets about how much pressure they can handle.

I end it here with you now. Further discussion not needed.

[bankruatsteve]

OK guys, enough.  Let's move on.

[sandyf]

I have a WP105 and would avoid it like the plague, had to change the tank after 18 months and now have to bump start it each time I use it. I just use it it empty the waste water tank.

I would suggest that you look at a Hitachi, the 150 size, I have that on the house and been working without a problem a lot longer than the Mitsu.

[giddyup]

1 minute ago, sandyf said:

I have a WP105 and would avoid it like the plague, had to change the tank after 18 months and now have to bump start it each time I use it. I just use it it empty the waste water tank.

I would suggest that you look at a Hitachi, the 150 size, I have that on the house and been working without a problem a lot longer than the Mitsu.

My Mitsu WP205Q is already over 10 years old and besides the tank rusting through it still works perfectly. Just had a new stainless steel tank fitted and imagine it still has a few years left in it yet.

[sandyf]

2 minutes ago, giddyup said:

My Mitsu WP205Q is already over 10 years old and besides the tank rusting through it still works perfectly. Just had a new stainless steel tank fitted and imagine it still has a few years left in it yet.

Yes, seems to be a common problem with the Mitsu. My sister in law has a 255Q, somewhere around 15 year old, and the tank is leaking on that. They keep patching it but a short term fix, needs a new tank. Your quite right, properly maintained should last for years to come.

The other problem with my 105 is the flow is quite low compared to the 150 size. I think the capacitor on the motor has gone but can't be bothered removing it from situ to repair, maybe deal with it if something else goes wrong. 

 

[giddyup]

1 minute ago, sandyf said:

Yes, seems to be a common problem with the Mitsu. My sister in law has a 255Q, somewhere around 15 year old, and the tank is leaking on that. They keep patching it but a short term fix, needs a new tank. Your quite right, properly maintained should last for years to come.

The other problem with my 105 is the flow is quite low compared to the 150 size. I think the capacitor on the motor has gone but can't be bothered removing it from situ to repair, maybe deal with it if something else goes wrong. 

 

I patched my tank 3 times with epoxy, but I was fighting a losing battle, a new stainless tank cost 2300 baht, so still a lot cheaper than a new 6000 baht pump. Fortunately the pump is only used when the town water supply is low or non-existent, which happened regularly during the drought.

[Surelynot]

On 9/4/2020 at 2:33 PM, impulse said:

 

Typically, the maximum pressure isn't what changes.  That's determined by the diameter of the impeller.  It's the flow rate that changes because the impellers have wider vanes for more flow.  Of course, that requires more power, so a bigger motor.

Interesting ......pumps do not generate pressure.....they impart kinetic energy to a fluid.....it is downstream devices resisting the flow that give rise to pressure.....moot point, but as I say....interesting.

[Yellowtail]

5 hours ago, sandyf said:

 

The other problem with my 105 is the flow is quite low compared to the 150 size. I think the capacitor on the motor has gone but can't be bothered removing it from situ to repair, maybe deal with it if something else goes wrong. 

 

 

You mean you get less flow from the small pump than the big pump? That's hard to believe, are you sure?

[sandyf]

18 hours ago, Yellowtail said:

 

You mean you get less flow from the small pump than the big pump? That's hard to believe, are you sure?

Sarcasm is the lowest form of wit.

As usual on this forum the smartxxxe's jump out of context, you chose to ignore the OP enquired about the 105.

There is a much bigger difference between the operating pressure of the 105 and 155 than there is between the 155 and the 205. Even less between the 205 and 255, from the 255 up the operating pressure remains the same.

By the same token your thinking should be exponential rather than straight line.

[Yellowtail]

4 minutes ago, sandyf said:

Sarcasm is the lowest form of wit.

As usual on this forum the smartxxxe's jump out of context, you chose to ignore the OP enquired about the 105.

There is a much bigger difference between the operating pressure of the 105 and 155 than there is between the 155 and the 205. Even less between the 205 and 255, from the 255 up the operating pressure remains the same.

By the same token your thinking should be exponential rather than straight line.

 

It was meant to friendly banter, sorry.  Yeah, I'm a linear thinker.  Would not exponential result in a nervous breakdown?

 

In any event, with pump selection, volume is generally much more important (and expensive) than pressure. A high volume low pressure pump will provide a much better shower that a low volume, high pressure pump, yes?

[sandyf]

12 minutes ago, Yellowtail said:

 

It was meant to friendly banter, sorry.  Yeah, I'm a linear thinker.  Would not exponential result in a nervous breakdown?

 

In any event, with pump selection, volume is generally much more important (and expensive) than pressure. A high volume low pressure pump will provide a much better shower that a low volume, high pressure pump, yes?

No in both cases.

Flow is dependent on pressure and pipe size, with smaller pumps the operating pressure varies up to a certain size.

The higher the pressure the higher the velocity at the outlet, and velocity is what most people want, hence the introduction of variable shower heads.

We have 2 bathrooms and the shower in one is better than the other because it is nearer the pump resulting in less pressure loss.

Flow is a different matter altogether and primarily to do with demand, back in the UK my shower temperature shot up if someone flushed the toilet or the washing machine started to fill.

A few years back I set up a sprinkler system from a very high volume pump, I had 8 sprinkler heads attached and it took me several days to adjust the flow in each leg to balance the outputs.

[Yellowtail]

5 minutes ago, sandyf said:

No in both cases.

Flow is dependent on pressure and pipe size, with smaller pumps the operating pressure varies up to a certain size.

The higher the pressure the higher the velocity at the outlet, and velocity is what most people want, hence the introduction of variable shower heads.

We have 2 bathrooms and the shower in one is better than the other because it is nearer the pump resulting in less pressure loss.

Flow is a different matter altogether and primarily to do with demand, back in the UK my shower temperature shot up if someone flushed the toilet or the washing machine started to fill.

A few years back I set up a sprinkler system from a very high volume pump, I had 8 sprinkler heads attached and it took me several days to adjust the flow in each leg to balance the outputs.

 

Whatever

 

 

 

 

[cjinchiangrai]

On 9/5/2020 at 10:46 PM, billd766 said:

You can always put a shut off valve both before and  after he water pump. That way you can alter the flow of water into the pump and the output pressure going to the house.

 

Thathas the advantage of isolating the pumpif you ever need to replace it as you have to now.

NOOO!!! Never  throttle the suction side, it will cause cavitation and trash the pump quickly.

 

If you really need to throttle the discharge, you should consider a smaller pump. 

[sometimewoodworker]

7 hours ago, cjinchiangrai said:

If you really need to throttle the discharge, you should consider a smaller pump

Or get an inverter where the pressure is adjustable on the pump itself.

[Yellowtail]

Closing the valve partially will not change the static pressure, it will only change the volume. 

 

 

Edited September 26, 2020 by Yellowtail
missed word

[billd766]

12 hours ago, cjinchiangrai said:

NOOO!!! Never  throttle the suction side, it will cause cavitation and trash the pump quickly.

 

If you really need to throttle the discharge, you should consider a smaller pump. 

Doing it both sides means that I can easily replace the pump. Something I have had to do about every 4 or 5 years.

[Yellowtail]

1 hour ago, billd766 said:

Doing it both sides means that I can easily replace the pump. Something I have had to do about every 4 or 5 years.

 

He's not advising against having a valve before the pump, he is advising (rightfully) against using the valve before the pump to throttle or choke the pump. 

 

 

[billd766]

4 hours ago, Yellowtail said:

 

He's not advising against having a valve before the pump, he is advising (rightfully) against using the valve before the pump to throttle or choke the pump. 

 

 

I don't use it for that purpose but for replacing a broken pump much more easily, but only if you use the same brand of pump. The first one I replaced had the inlet and outlet at 180 deg. The replacement had inlet and outlet at 90 deg, which made it very awkward to replumb.

 

Whn we built the place 16 years ago the nearest house was 500 metres on one side and nearly 1 km on the other. The mains pressure alone (no pump) could reach at least 10 metres high.

 

Now there is no room left and I have a resort next door and another 2 doors away on the other side.

 

The only thing that has not changed is the main water pipe which is still only a 2 inch diameter pipe.

Edited September 26, 2020 by billd766
Bad spelling

[Yellowtail]

6 minutes ago, billd766 said:

I don't use it for that purpose but for replacing a broken pump much more easily, but only if you use the same brand of pump. The first one I replaced had the inlet and outlet at 180 deg. The replacement had inlet and outlet at 90 deg, which made it very awkward to replumb.

 

Whn we built the place 16 years ago the nearest house was 500 metres on one side and nearly 1 km on the other. The mains pressure alone (no pump) could reach at least 10 metres high.

 

Now there is no room left and I have a resort next door and another 2 doors away on the other side.

 

The only thing that has not changed is the main water pipe which is still only a 2 inch diameter pipe.

I know my Mitsubishi pumps have blanking plate the allows you to install at 90 or 180 degrees.