This question is regarding Grundfos 1.5 Bar Negative Twin Impeller Amazon Brass Negative Head Heavy Duty Regenerative Shower Pump

pump specs

Hi I need a negative head pump but am a bit confused about the regenerative part. As I understand it it is not the same thing? Also my existing pump is fed on 15mm, what size are the feeds and load for the hot and cold. If 22mm is it ok to reduce it? I have also read means the pump should be sited within 2m of the emersion and 5m for a 22mm pipework.
Asked 5 years ago by Otto
Yes you are a little confused with the terminology used when discussing pumps so it is making it a little difficult to answer your question..

If you go to the link below we have 3 videos on pumps which should help, after you have had a look at them any questions get back to us.

www.youtube.com/results?search_query=Showerdoc+pumps

Answered 5 years ago by George Thomson

Hello,

I watched you video but it doesnt answer my question. Is the regenerative pump used for negative head? When can it be used? What about the pipe size?

I had a shower installed and the pump failed twice. The shower pump was installed at the level of the water tank so it should have been a negative head pump. On my research for a new pump I came accross the issue with the pipe feed size in relation to the proximity to the immersion. The current installation is 15mm and over 2m away, hence the question. I can't replace the pipe work.

I am running both hot and cold from the pump.

The advertising blurb and various web site discriptions and specs are unclear an d contradictor, also do not fit the look of the pump in the pictures.

As far as I can see I can make out I need a twin head (hot and cold) negative or universal (not sure if regenerative will cope with negative head) and a 15mm (3/4 BSP) connection.

Your video mentions the salamander. Can you tell me what pumps I can consider.

Answered 5 years ago by Otto M

A negative head / universal pump can be a Centrifugal or a Regenerative type.

Depending on the usage , you may need a large or small bar pump.

Correct fitting following the manufacturers up to date guide lines is best way forward when fitting a new pump.
Minor alterations or additions to pipe work may be needed to assure a new pump is covered by the warranty.

Salamander offer a service called PumpWise which help customers to choose the correct pump for its applications.

Answered 5 years ago by Barrie Seabright

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