Negative or Positive head shower pumps

[Magrah]

What's the difference? I think posative means pressured inlet and negative means no pressure inlet, is that right. May help if I told you the issue.

Need to run two electric showers but don't want them running off the main due to the old problem of another outlet in the house gets turned on and effects pressure. So in my old house used a Salamander ESP80 below the tank (about a meter below) and that could run both showers all day long.

New prop planning a similar sytem, but is the ESP80 the best option, or should I use Techflow or Stuart Turner options?

Any pointers would be appreciated.

Thanks

 

[seco services]

The ESP 80 is ideal for a electric shower if using a salamander pump as it needs to be a negative head pump.
positive head pumps won't work on electric showers.

 

[Magrah]

Many thanks, but any views on the Salamander vs other makes, the ESP is around £300, but Tech do a 2 bar pump for £115 and also do a ultra silent one for about £250.

 

[Richard C]

You get what you pay for & £115 for a 2 bar negative head pump says it all really . The Sally ESP 80 will be fine but I’d go for a Stuart Turner Monsoon.

£300 for an ESP is a bit steep, you need to look around some more. Ideal Plumbing has them on flea bay for £236 or £267 for the STM 2 bar.

 

[Magrah]

Thanks Richard

Sent a q to ST and they have said need the Monsoon Universal 4.5 bar, that around £270, dug a bit and can get the Salamander ESP 80 2.3 bar for around the same money (excluding the bay).

Question is which one! I don't quite understand why one is 4.5 and the other 2.3bar but used the ESP 80 for 5 years before selling the house. The only thing I would say is it was meant to be 'ultra quiet' and is wasn't even with extra damping!

 

[Richard C]

Neither do I; christ a 4.5 bar for one shower My only experience is on vented storage systems however so never fitted one to an electric shower before but that seems rather large, perhaps seco can comment.

I’ve fitted both ST & Sally & find the ST to be much quieter; in fact my own pump is a Sally RHP (now 4 years old) but if/when it gives up the ghost, an ST will be going in.

 

[seco services]

I agree with richard 4.5bar sounds over the top
i've never fitted a pump that powerful even for a whole house situation
about 3 bars has been adequate i think.

I gave the esp as an example and one that i have fitted and found it to be more than enough pressure.


Providing your electric shower gets a min of 1 bar to operate it thats fine.
so i'd be happy with 1.5/2.0 pump in that situation
but 4.5 bar is abit extreme.
Another thing with electric showers i find pushing to much pressure through them can cause problems even on mains feed i try to keep the pressure below 3 bar.

so all in all the 4.5 bar is a no no for me.

 

[Magrah]

Yep it’s too much; the chap did say that you need 1bar for the shower to operate properly, so you'd think 2 or 2.5 would be fine for two. The other point is they will probably in reality rarely run together.

The ESP ran both perfectly at my old property on those rare occasions; one was an 8.5kw and the other 9.5kw.

And as you say I think the shower valves don't like really high pressure.

So it's the ESP or the 2bar ST Monsoon I think, just wish I knew which was quieter!

 

[Richard C]

Yep it’s too much; the chap did say that you need 1bar for the shower to operate properly, so you'd think 2 or 2.5 would be fine for two.

Depends on pipe work resistance, the head your pumping & flow rate of your showers; 2 bar should be OK but, depending on above, might struggle a bit if your likely to be running both showers together; in this case, 2.5 would be a better bet.

So it's the ESP or the 2bar ST Monsoon I think, just wish I knew which was quieter!

I’ve fitted both ST & Sally & find the ST to be much quieter

 

[Magrah]

Many thanks Richard.