Booster Pumps and Diagram Tanks

[rs4duke]

Hi All,

Can anyone tell me if a booster pump is required to have diaphragm tank? I am reviewing a project that was done before my time at the company and the designer provided a Grundfos Magna3 as the booster pump with no diaphragm tank. I have never heard of the Magna3 being used as a booster pump and we are having pressure issues at the site. My understanding is that the Magna3 does not add boosted PSI but draws through what the pump is set for. I typically use them for hot water circulation. I also noticed that there was no pressure switch provide downstream of the pump to tell the pump when pressure is low, could that be the issue?

Just trying to help resolve the pressure and hot water timing issues at the site.

Thanks for any help that can be provided.

 

[speedbump]

If your using this pump (which I am not familiar with) for circulation, it's not a booster pump. Booster pumps do not need a tank to increase pressure. All they need is something to turn them on and off; like a flow switch. A pressure switch and tank can be used, but it' not the best method. The best pumps for boosting pressure are jet pumps and end suction centrifugals. The centrifugals have better flow and the jets have better pressure.

I got curious and looked up the Magna3. It is a circulation pump not a booster.

I also re read your question. You said: if a booster pump is required to have diaphragm tank? No diaphragm tank would be needed without a pump. Tanks do not make pressure.

 

[rs4duke]

Thanks for the reply Speedbump. I had the Grundfos people meet me on site yesterday to look at the pump. It is being used for domestic water boosting and not circulation. They were able to adjust the people so that the owner was happy but this didn't resolve the hot water issue. I've come to the conclusion that there is just TOO much hot water pipe to not have a hot water re-circulation system.

 

[speedbump]

Sounds to me like it was misapplied if used for boosting. Circulators normally won't make much pressure at all.