Flow Limiters

[muzzmackay]

Just got a new mixer shower, which I will be feeding from the combi boiler.

The manual has a flyer saying that it is fitted with flow limiters which must be removed if the water pressure is low. Now I reckon the cold water is fine but I'm not sure about the hot water.

I read in another thread that you can count how many litres a hot tap produces in 1 minute, nine litres being satisfactory, is this a good guide ?

Is there a major down side to just removing the limiters ?

 

[simond]

Normally when we talk about a shower flow limiter from the shower manufacturer - which is typically a washer with a hole in it - it is designed for use with a combi.

Reasoning is that the combi (depending on type) will typically allow less water flow down the hot pipe than you have at your disposal down the cold. Without the washer (sorry, flow restrictor) the shower adjustment would be biased towards a cold shower.

If you have a good mains supply and a fast hot water combi you may not need to put it in......

 

[chrishutt]

Both hot and cold are subject to the same static pressure (mains) but the dynamic pressure when the water flows will be much lower on the hot side due to the resistance through the combi (which may contain a flow limiter). Therefore putting a flow limiter on the cold side may improve the balance between supply pressures and therefore performance, but only if the dynamic pressures are very different.

 

[muzzmackay]

If you have a good mains supply and a fast hot water combi you may not need to put it in......

Do you mean I may not have to remove them ? I have taken off the swivel elbows to have a look and theres some weird plastic inside, the hot is a different colour and has a different number on it than the cold. Looks like I need some special tool to remove them too.

 

[muzzmackay]

Therefore putting a flow limiter on the cold side may improve the balance between supply pressures and therefore performance, but only if the dynamic pressures are very different.

I just did the test to get a netter idea of the difference. I used the bath taps. The hot taps produced 8.5l in a minute whereas the cold had passed the 12l mark in half a minute. I think I will remove the hot limiter and leave the cold one in.
Just for info, the flow limiters have been fitted as a requirement of " NHS Model Engineering Specifications D08 " . Sounds like some interesting bedtime reading for someone