Reducing water pump pipe from 1" to ½"?

[Dellian]

I'm getting nowhere searching and translating Pantip plaza and I could use some help.

 

The municipal water is always shutting off and I want to install some water tanks and a pump. Everything on my property is unfortunately ½" pipe. From the tanks to the pump it will be a 1" pipe that will then need to be reduced to attach to the house. The house is a single story with 2 bathrooms, a kitchen and a laundry. We have a large garden that gets watered everyday. 

 

The concerns and questions I have are:

Does reducing the pipe size mean I need to be mindful of how powerful the pump is? (I was thinking a Hitachi 250W but now erring on the side of a 150W/200W)

Can I reduce the pipe size soon after the pump? (there are pavers surrounding the house that will make replacing the existing ½" pipe a nightmare of a job)

Would it be better(safe?) to just reduce the inlet and outlet of the pump?

 

I've attached a rough diagram that shows I have a dedicated pipe surrounding the property for the garden and the mainline that will connect straight to the house. 

 

Any help would be appreciated immensely. Thank you. 

 

[Artisi]

Just reduce the discharge pipe to 1/2" where ever it best suits you.

 

Best pump to consider is a constant pressure type, these runa lot smoother than the bladder type pumps. 

[Dante99]

11 hours ago, Dellian said:

Can I reduce the pipe size soon after the pump?

Yes you can but I think you would get better flow and pressure if you ran the 1” thru the two T fittings and reduced after those fittings.  So you would reduce on the right side of the T to he house and on both sides of the garden T.

[SLOWHAND225]

Just remember:
Bigger pipe = reduced pressure/more volume
Smaller pipe = higher pressure /reduced volume

 

You'd be better off to run 1" all the way to the point of use. ** if your pump is big enough.
Always better to have too much pump than not enough

[carlyai]

'Always better to have too much pump than not enough'

Just have to be mindful of the people that origionally installed the .5" pipe.

 

You don't want a pump too big that it could break one of the pipe joints that are under the cement and tiles.

My .5" water pipes were installed by local farmers who swore they had Dr Degree in Water Flow and pipes.

300 W pump and a few under cement leaks.

 

[Dellian]

Appreciate the help all.

 

8 hours ago, Dante99 said:

Yes you can but I think you would get better flow and pressure if you ran the 1” thru the two T fittings and reduced after those fittings.  So you would reduce on the right side of the T to he house and on both sides of the garden T.

 

This is a great idea, thank you. 

 

[SLOWHAND225]

8 hours ago, carlyai said:

'Always better to have too much pump than not enough'

Just have to be mindful of the people that origionally installed the .5" pipe.

 

You don't want a pump too big that it could break one of the pipe joints that are under the cement and tiles.

My .5" water pipes were installed by local farmers who swore they had Dr Degree in Water Flow and pipes.

300 W pump and a few under cement leaks.

 

In this case the pump would have more volume or GPM, not pressure or PSI
1/2" pvc and 1" pvc both can handle the same pressure

Sorry to hear you had leaks, it happens.

[carlyai]

18 minutes ago, SLOWHAND225 said:

In this case the pump would have more volume or GPM, not pressure or PSI
1/2" pvc and 1" pvc both can handle the same pressure

Sorry to hear you had leaks, it happens.

Agree that both can handle the same pressure, but the relay setting on my larger pump was higher. 

Also nothing was pressure tested to my knowledge. I was doing a million things and left it up to the guys who knew all about water and pipes.

[sandyf]

20 hours ago, Dellian said:

Does reducing the pipe size mean I need to be mindful of how powerful the pump is? (I was thinking a Hitachi 250W but now erring on the side of a 150W/200W)

To a certain extent. The bigger the pump the greater the ability to maintain the same pressure against greater obstruction.

There is very little difference in the pressure, the smaller pumps are a bit lower but once you get over 150 I think they all thave the same pressure switch settings, 1.4 -  1.8 bar.

I had a Hitachi 200 on the house, and that worked ok with 1/2 throughout the house and It lasted about 12 years before the tank developed a pinhole from corrosion. I replaced it with Hitachi 250 constant pressure pump thinking I would get a better shower, that is when I realised the pressure settings were the same.

We have a well that we use for the garden so do not have the same problem. There is a good chance that you could see a pressure drop in the house if the garden hose is in use so I would suggest you consider a 300 model. Wouldn't be a great deal of cost difference and possibly remove an annoying pressure drop.

I didn't throw the 200 away, bought a stainless tank from  lazada and used it to replace a small Mitsu I had on the waste water system.

Good luck.

[sandyf]

9 hours ago, carlyai said:

'Always better to have too much pump than not enough'

Just have to be mindful of the people that origionally installed the .5" pipe.

 

You don't want a pump too big that it could break one of the pipe joints that are under the cement and tiles.

My .5" water pipes were installed by local farmers who swore they had Dr Degree in Water Flow and pipes.

300 W pump and a few under cement leaks.

 

 

The pressure switch on a 300 is 1.6 bar nominal and will cut out well before a proper pipe joint gives way.

Bad joints on the other hand tend to leak.

[ExpatOilWorker]

1/2" is fine on the discharge side of the pump.

Select a pump around 250 W, they also have the 1" suction/discharge connection that you want.

 

https://www.mitsubishi-kyw.co.th/Product/For-Home/Water-Pump.aspx