Good schema for electric and manual water pump system

[rcarlucci]

Hi to all,
I am new to this forum and living in Italy.
I have a problem with my water schema for toilet and kitchen, and maybe something can be added to the treath:
http://www.ybw.com/forums/showflat.php/Cat/0/Number/909249/page/0/fpart/1/vc/1

I try to show with following piping schema:

WT=> EP => Y to outside shower
................Y ST=> FP => toilet tap
Where
WT=Water Thank
EP=Electric Pump
Y= Y pipe connection
ST=Security closing tap
FP= Foot Pump

Before the footpump (Whale Galley MK3) there is a closing tap to prevent damage to the footpump.
So everytime I use the shower I have to manually act on this closing tap.
Any idea to avoid the tap before the manual pump?
Thanks
Renzo

 

[DaveS]

I don't quite see what benefit this stop valve gives. The footpump shouldn't normally be damaged by pressurising its input - indeed that's how my system works: the tap normally delivers water under electric pump pressure and, if the electric pump's off for whatever reason, I can still use the footpump.

The only possible problem could be if the electric pump develops a pressure so high that it could burst the footpump. The other leg of the "Y" feeds a shower. Your electric pump isn't a high pressure "power shower" pump by any chance? If it is, then a more elegent solution would be to replace it with a low pressure "booster" pump then re-site the HP pump between the "Y" and the shower.

 

[rcarlucci]

The electric pump is a Jabsco Diagphram (but I don't exactly know the model). I don't think it is high pressure.
Renzo

 

[homa]

I suppose it depends upon the pressure of the electric pump, but on a previous boat I owned the Whale Galley Gusher foot pump was isolated by shut off valves.
On 2 occasions I managed to split the diaphrams on this pump after turning on the electric pump, and I had forgotten to isolate it (foot pump) properly after a winter lay up.

 

[DaveS]

Now you've got me worried!

My electric pump is a titchy little thing, can't remember the make, but cheap, cylindrical (c. 30mm dia. X 80mm long) and mounts in-line. It lifts the water c. 1m and judging by the flow rate at the tap I would guess (although I haven't actually tried it with a tube to check) it might be capable of lifting anonther 2m or so. So maybe 0.3 bar or so. I've always assumed this was far too low to cause damage to the foot pump, but maybe I've just been lucky (so far). Do you know what sort of pressure your electric pump developed?

 

[rcarlucci]

This is exactly what the previous owner of my boat said me. He had the same problem so that he added the shut off valve.
Renzo