For your size of house, 1 to 1.5 HP is sufficient. This is quite a standard power.

Since yours is a new house, there should be no problem with pipes bursting. The pipes are normally rated to withstand 10-15 bar pressure. Your pump is only putting out 3-4 bar.

The problem usually occurs with old houses where the pipes and the joints (especially) are more worn. Installing a pump then may cause the weak areas to leak.

This post has been edited by jchong: Nov 21 2016, 12:31 PM

Can you explain how those switches/relays help to prevent over pressure?

I thought to reduce over pressure, you need pump with inverter or variable speed drive.

Hi, I am looking for the water for 3 bathrooms (New double storey), 2 upstair and 1 downstair. Please recommend. I concern about the bursting of pipe. Will the pvc pipe easily get burst by high water pump pressure? Beside, any recommendation of seller nearby Semenyih area?

herm, regarding pipe bursting, notice many customers and forumers asking about this. If you ask your friends or families, i bliv most of them do not have issue with pipe bursting, in fact i have been selling Grundfos pumps for more than 10 years, the number of cases pipe leak not burst is less than 10.

How to size your pump?
1) not by HP but most contractors or plumbers do suggest by HP.
Different brand with smaller HP could generate higher flow rate and pressure. HP is just the motor electricity consumption not the actual performance of the motor, using the same motor but having more impellers could increase flow rate. Grundfos CM3-4pm1 with 0.7hp could pump 3.7 bar but CM3-5pm1 with 0.7hp (same hp) can pump 4.6bar

2) how many bathrooms and what type of shower system?
You can have 5 - 6 bathrooms but only using 4" hand shower, a grundfos CM3-5pm1 is sufficient (max output 70L per minute), a normal hand shower only require 6-8L per minute. However, if you are using 10 or 12" big rain shower heads then you will need a stronger pump like CM5-4PM1 (105L per minute)

Looking on the bright side, the pump is acting as a leak detector. Helps alert you if there is any leak in the faucet or pipes.

I've read there are some pumps that can be controlled by flow rate, i.e. once a certain flow qty is required then only pump turns on. Therefore, minor leaks will not cause the pump to turn on.

I see your meaning for relay now. Yeah, the wiring is gonna be more difficult. Gotta hack the wall if you want to conceal it. I think most house owners won't choose to do this.

Tapping to bathroom light or heater also means you need to turn on the light or heater every time you shower, which isn't always necessary.

hi,

my 2storey house situation

1. fill up tank first
2. if filled up then direct from main (whole house)

i need to increase a water flow from a tap 2nd floor balcony for pumping water pool.. any idea what is the fastest way to do it?

This post has been edited by braun.buffel: Nov 23 2016, 09:09 AM

Hi, i want to check the installation of water pump by pass method as above image, is it correct?
does it need valve to control by pass? or it will auto by pass when the pump is off or failed?

u drew yourself? else, refer this guide, was drawn by a sifu:

wow thanks, anyway the valve is always open and only use if got maintenance right?

and i notice yours is by pass between direct and tank, how bout by pass pump?

This post has been edited by IceBikers: Nov 23 2016, 03:03 PM

ball valve needs to be before the non return valve.
can close to change out the non return valve if required.

bypass the pump also can use the same concept. need non return valve.
else the pump discharge will pump back into the pump suction.
waste energy.

I have a grundfos pump CH2 - 40 which I have used for nearly 10 years without problem.
I notice recently that the pump does not switch off automatically like what it ised to be and the water is hot even at night when the pump is not switching off automatically. It seems like at times the pressure switch work and at times not.
What should I do? Can I ask anyone to check/repair or I need to replace the pump?
Thank You.

if you have non return valve it maybe the hot water is reverse flowing out of the tank.

pump does not auto shut down is due to malfunction pressure switch. If part is not available due to obsolete, then remove the switch and rewire into direct connection. Add an inline standalone pressure switch instead.

Thank you for the reply.
The pump is hot when I touch it and today there is a small leak at the connection but when I off the pump and on it back the leak stops. The overpressure may have caused the leak.
Who should I contact then. Not all plumber knows about water pump.
My option is to seek feedback from the bigger hardware shop that sells grundfos pump but they may ask to replace the pump instead.
TQ.

Plumber is just plumber at most they can take it out for you and send it to repair. They cannot repair for you.

If you piping have a bypass setup incase pump need to remove is easier. Else your plumber need to do the bypass for you.

Is better you switch it off if not using, running pump non stop may cause pump overheat, house piping crack.

Alternative is buy a new pump ask plumber replace for you.

Installing Pump is a plumber's work. Repairing pump/rewiring pump is a electrician's work.

Actually a lot of the pump does not have or a weak pressure switch. And adding a standalone inline switch is way better than using the built in one. But here, like everything else, market progress is very slow and people are selling old tech at premium like as if it is the greatest invention of the time. So for your convenient, you can also let it be as a direct connection and use wall switch to manually turn it on and off.

What is the purpose of Bypass pipe? My plumber install the water pump without it.

What happen if you pump need to be remove and send to repair? what happen if pump is leaking while waiting for plumber to come over?

Oh, OK, Now I understand. Thank. from the previous message above, there is 2 picture, one is the bypass pipe is before water tank, one is after water tank. Which one is correct?

I also have the problem after installing the water pump. My water pump is install at the roof of 2 storey house. In my house, I can't hear a noise of water pump. But the problem is my neighbour hear the motor sound echo of my water pump, and start complaining, and call me to dismantle the water pump.

Any sifu here have the solution for this?

one of the things you need to consider.

you can sound proof it by making sure it is installed on a solid surface, add a rubber/silicon pad in between pump base and installed surface and if it does not help, you have to cover it in a sound proofing box.

If these does not work, you should move it to ground. This will require you to reroute your water supply a little bit. But not disturbing neighbour is one of the top priority.