Centrifugal water pump

[stagedamager]

Evening all!

We are looking at swapping out the water pump on Oak as it's sounding ropey as hell. Having two kids we are running a washing machine daily, and truth be told I'm not sure if the pump is up to the continual demands placed on it. Also the noise is truly awful, due to its location under the dinette seat. So. We're looking at the option of a centrifugal pump instead of a diaphragm one. Has anyone had experience of these, or have on installed? I'm guessing it would need a strainer and NRV on the inlet side and an external pressure switch, but any advice would be marvellous!

Regards

 

Dan

[alan_fincher]

Unless I'm misunderstanding what you mean by "centrifugal pump", I would not have thought most would supply the kinds of pressures usually used for narrow boat plumbing.

Do you have a link to an example you have in mind?

[ditchcrawler]

I would suggest the NRV with the pressure switch upstream of it (towards the taps and accumulator) If you don't have a strainer now I don't see why you will need one with the new pump.

Unless I'm misunderstanding what you mean by "centrifugal pump", I would not have thought most would supply the kinds of pressures usually used for narrow boat plumbing.

Do you have a link to an example you have in mind?

Our water systems offshore use to be via centrifical pumps

[stagedamager]

http://www.stuart-turner.co.uk/products/stuart/1250/1250-12-v/

[WotEver]

http://www.stuart-turner.co.uk/products/stuart/1250/1250-12-v/

15A!! Wow that's a demanding pump.

 

Tony

[smileypete]

May also need a decent accumulator.

 

The pump mounting method and location can make a lot of difference to noise and ease of replacement, any details or pics of the existing?

 

Putting a relay between pressure switch and pump will avoid issues with the pressure switch wearing out, the motor is usually very reliable. Maybe keep an identical spare, could even pipe it in for instant backup.

[Tony Brooks]

FWIW Godwin made a centrifugal domestic water pump mounted on its own "accumulator" and NRV. These were in my view far more trouble free than then common Jabsco Water Puppy systems and the American diaphragm pumps. I second what Smiley Pete says about using a decent accumulator and also what Ditchcrawler says about the NRV.

 

The only long term problem we found was that the impellers tended to block with rust/scale/hair so the pump lost output but a strainer in the inlet side should solve that. They are also not self priming so may need a suck on a tap if you run out of water.

 

The noise of your existing pump - is it screwed hard down or are the screws all loose, they should be loose so the rubber feet can damp the vibrations. Is it connected to the system by FLEXIBLE pipes. If not the pipes tend to make the nose worse.

[Leisure boater]

It would be worth taking it appart as it is more likely to be the bearings gone and they are only a few sqid to change you can get replacments from any bearing supplier they will either cross match or measure. My pump is on its second set and getting to need another at 20 years use.