Do more bends = less pressure?

[templar06]

Howdy all.<BR>We have very low pressure to our shower. Its a low pressure system but since changing from a manual mixer to a new thermostatic bar type mixer it is now non existant. Well nearly, its 750ml per minute at the shower head! On nosying about in the loft there have been previous pipe amendments which include adding more bends than necessary to the hot water inlet! Looks like 3 have been added. The previous owner appeared to be quite thrifty and I was wondering if by adding these that he may have purposely reduced the flow rate in order to save on hot water. <BR>So then, do more bends equal less pressure in a low pressure system?<BR>Many thanks in advance.

 

[shneld]

I think im right in saying this, more bends/longer run will reduce the flow rate, but not the pressure.

 

[Paulus]

Bends will make a tiny difference. A thermostatic valve has more gubbings inside which reduce pressure. You almost certainly need to fit a shower pump.

 

[Plumbstar Tom]

As mentioned bends will reduce the flow but not so much, if you take them out you might get 1lpm

Thermostatic valves are more restrictive than manual ones

I would advise that you look for a shower pump

Pop it next to the base of your HW cylinder and your good to go

 

[kay-jay]

the product you have bought is not suitable for low pressure systems. you will need a pump as said above

 

[templar06]

Many thanks for your comments.
Just thought I'd check before I try the pump route or take it out and install an electric one.

 

[Resolute]

Be careful if putting in an electric shower as if you have low pressure then you may experience problems there too. Your money would be best spent on a pump.

 

[REDSAW]

it should state the min head and flow rate on your bar mixer guide.
typically a low pressure type would be efficient at 0.2bar, that is-shower head 2meters below storage tank.
if not pump it.

 

[pobsdad]

A lot of bar mixers have built in check valves,which are unnecessary in a low pressure system,as long as the hot and cold are equal.On some models these valves can be removed,greatly increasing the flow (and possibly invalidating the warrenty),but on the right system,this can make a massive difference.If the cold is on mains,don't even think about it,though!

 

[Billy Bob Bob]

if and by the sounds of it you need a pump look at stuart turner

 

[templar06]

Been looking at pumps, but this shower is supplied through the loft, mostly through 15mm pipe. It only becomes 22mm as it drops down into the bathroom. The 15mm runs are around 4m. Should the hot be in 22mm for the whole run? If it should be then I've no idea why it's not. It's the hot that is the problem.

 

[mylesy]

i dont know if your old mixer had mains cold or not, (un-ballanced pressures) but if your going to pump, which i also think you should. (its a nicer shower ) but if it was un- balanced just make sure you have a cold distribution pipe from the cistern aswell as hot but tap it in just under the hot outlet incase it ever runs dry ( you wont get burnt)

 

[Plumbstar Tom]

Sounds like hot gravity, cold mains

I would pump it defo, ideally would need to refit the cold supply to come from Cold storage tank to pump so completely balanced to hot

 

[mylesy]

yeah tap the cold just below the hot, doesnt have to be on same side, can if you want. its just incase it runs dry. hot will run out before the cold and you wont get scoulded.