Hi zheilwane,

Recently I went to inquire about Grundfos water pump and was recommended 2 options.  I do not know the model but i think it should be similar to the ones you recommended.

The first option has higher pressure but smaller inlet.  Hence can support up to 4 bathrooms only.

The second option has lower pressure but bigger outlet and hence can support up to 6 bathrooms.

I am a little confused here.  If the 2nd pump has lower pressure, how can it support more taps/showers even though it has higher flow rate?  Surely the pressure would reduced if there are more people using the shower/tabs?

Which is a better option?  I have 6 bathrooms but i doubt all will be used at the same time.

Just a quick question, where did u purchase the pump from? The seller cant help u? You should really buy from some1 who is professional and could give u good advise. For example, if ur plumber has done the piping as per ur photo, you will have some problems after the installation....

a) The most important thing, you need to install PVC unions as per grundfos requirements.

b) If cold water is boosted by the water pump while the hot water is using water tank's water, your hot water pressure will b much weaker than the cold water. So, when u r showering, you will feel the water is not hot enough as u r getting more cold water than hot. Therefore, the tank's outlet should go into your pump then split to ur heater and down to your bathroom. By doing this, you will have same pressure for both hot and cold.

c) The pump by pass is wrong. Imagine u r using 8-10" rain shower but ur pump is out of order, so you will b using the pump by pass. However, the water supply is from the tank, do you think u will have sufficient water pressure to power up the rain showers? You should do a main water by pass instead.

Here is how the installation should look like


Hope that answers ur question

What do you mean by wails?

What do you mean by wails?

Few things you need to make sure

01) Pump is sitting on a secure surface
02) Pump is sitting on the anti vibration map
03) The outgoing pipe from the pump need to be fully secure. My contractor actually screw / nail the outgoing pipe to a wood where the wood are secure to the roof truss.
04) A good pump of course

I am using grundfos, i don't hear hammer sound. Sound sure got when the pump is on, is not loud, and it won't wake you up during sleep

Sound like the boiler inlet are not from pump, that is why you get low pressure for hot water.

Yes, I realise this is a possibility after looking at the drawing updated by Zane!!!!!

I read you also switch on the pump 24/7? Is actually recommend to put the on/off switch inside to only switch on when require.

the pump can be on 24/7 cause there is a pressure switch..

I guess your plumber mounted the water pump on a wall. When the pump vibrates a little, the vibration will travel down to ur house and the noise is also amplified.

Not very difficult to do the stuff above but due to CNY is around the corner, it will b costly to do so (plumbers will hike up the price).

If you wanna get the problem solved quick, jus drop by my shop and speak to Thomas, he would b able to give some good advise.

Hi guys,

I just got my key for a sub-sales 10year old DSL house. Renovation will start after CNY.

The water pressure is "OK" for now. But has been planning to 'upgrade' my master room toilet with bathtub and normal instant heater. Here are some of my questions, hope can get some advice.

1. The house is vacant currently, the meter reader is the same since the 1st time i walk in until today, (more than 2 weeks), so do this means that the house no pipe leak?

2. The risk for installing Grundfos pump, is possible that the original pipe cannot take the pressure and cause water leak on the join?

3. Do Grundfos pump required yearly maintenance?

Thanks