Salamander pump water supply max distance

[numnuts]

can anyone help me please. I am intending to fit a Salamaner RSP100 shower pump into my new extension. In the fitting instructions it says the hot water supply must be a maximum distance of 4m from the pump and should be in 22mm pipe.

The 22mm pipe is not a problem but the nearest I can get the pump to the water cylinder is 4.3 meters. Will this make adiffence?

Has anyone any experience of this?

Please help if you can, it's worrying me to death!!

Numnuts

 

[seco services]

can't you get it in the airing cupboard or loft ?

 

[numnuts]

No the airing c upboard is no way big enough and salamander have told me I need a different pump for fitting in the loft. I have looked at every option and the only sensible way for me to fit the pump and plumb in the pipe work is in the location that is just too far away for Salamander's liking. I realise I effect the warranty but I can live with that.

 

[Richard C]

What Salamander worry about is the effect a low (gravity) supply velocity can have on the pump unit i.e restricted flow & cavitation which can destroy the impellers in a relatively short time. In all honesty, I can’t see that an extra 0.3m is going to make an awful lot of difference as long as you have a good supply, any valves in the circuit are “full flow” & the pipe route to the pump is more vertical than horizontal.

I’ve got an RHP 75 pump running a whole house system & 2x power showers. I had all sorts of problems due to the fact I had twin tanks, one of which is connected to a solar system & although the pump is within 1/2m of the nearest H/W tank, the furthest is 5m+ away up in the loft. After seeking advice, I gave up with the Salamander tech. bloke as much of what he was telling me didn’t make any sense; but I am an Engineer! So I didn’t get my extended 3 year warranty but it’s been running for over a year now with no probs; but I ain't gonna give you any guarantees!

 

[numnuts]

Richard C

Many thanks. I plan to use 28mm for the suction pipework. I hope that way any line resistance will be reduced. I also plan to increase my head pressure by about 500mm. This all together will overcome the 4.3 horizontal line to the pump. Total head should be about 2.7 - 3.2m.

I will then go back to 22mm for the discharge pipework narrowing to 15 mm at each of the 2 showers. Hope that will give enough back pressure to reduce cavitation to a minimum.

Any obvious flaws in my plan?

Numnuts

 

[Richard C]

Richard C

Many thanks. I plan to use 28mm for the suction pipework. I hope that way any line resistance will be reduced. I also plan to increase my head pressure by about 500mm. This all together will overcome the 4.3 horizontal line to the pump. Total head should be about 2.7 - 3.2m.

I will then go back to 22mm for the discharge pipework narrowing to 15 mm at each of the 2 showers. Hope that will give enough back pressure to reduce cavitation to a minimum.

Any obvious flaws in my plan?

Numnuts

I’ve got 22mm supply pipe work from both the hot & cold tanks to the pump at a head of 3.3m & this is more than adequate on our system; the governing factor will be the size of the cold water storage tank & the rate at which you can refill it. I would use 22mm mixer valves rather than 15mm, mine only reduce to 15mm at the shower head. A little more expensive but worthwhile for the higher delivery rate but it depends on the type of shower heads you using; mine are 250mm drencher heads.

 

[numnuts]

Mant thanks