Poor flow from electric shower

[dylan.gibson]

I have recently replaced my electric shower as the old one suffered from such a bad flow rate it wasn't worth using (it was a tritron 7Kw). So I thought I'd go for a gainsborough 10.5Kw SCL. Having installed this the flow rate has only marginally been increased. The shower I think takes it water from a sub pipe off the main and it seems to have some sort of limescale filter inbetween. My main question is would it be worth installing a pump to increase the cold water flow/pressure to the shower??

 

[kevplumb]

you can't pump the mains supply

 

[dylan.gibson]

If I can't use a pump then can you recommend anything I can do to improve flow. Would it be better to take the supply from my header tank (not so cold as mains) and pump that??

 

[chainsaw_masochist]

Was your old 7kw shower always prone to a bad flow rate or did it deteriorate over a period of time? If so, it might be well worth checking the in-line filter as this may have become scaled up, in which case you should clean it through.

As a basic check you could measure the flow rate of cold water mains tap. Using a vessel of known capacity, say a 15 litre bucket, time how long it takes to fill. If your results are less than 10 or 11 litres per minute you are going to have problems no matter what rating of shower you instal. Good luck.

 

[kevplumb]

upgraded the shower did you upgrade the electrics at the same time

 

[dylan.gibson]

Electrics were upgraded at the same time - New wiring, pull cord and consumer unit.

Is taking the water from my water-tank in the loft an option?? The idea being that that water isn't quite as cold as mains direct water so the shower wouldn't have to work so hard - the problem with it would be that the rise is only 1.5m - could a pump be installed between the tank and shower inlet with this methood??

It's all a bit frustrating really - the 7kw shower was already there when we moved in last year so I don't know if the performance has gradually deteriorated or if it was sudden. I spent extra money thinking that as I was getting a 10.5Kw shower the performance would be much better. The manual says the performance of the shower will always be better in the summer, but that's not really good enough!

 

[ChrisR]

Electric showers ALL give poor flow. You've got 10.5 kW whereas a shower from a combi is 24 or 28 kW.
MEASURE the flow at showering temperature.

10.5 x 60 /(4.185 x 32) gives about 4.7 litres/min for a 32 degree temp rise.

If the flow is restricted by a blocked filter the water will be very hot - worth a check.

 

[chainsaw_masochist]

No, you will not be able to provide a supply from the cistern, pumped or otherwise. The electric instataneous shower that you have, both the 7kw and the new 10.5kw, both require a mains supply.

First of all do the flow rate test as described. Then you need to check the pressure being supplied by your local water authority. To do this you will need to obtain a water presssure gauge. You should be receiving around 1 bar of pressure at mains tap. If it is less than this then you can take the matter up with the water authority as they are supposed to provide a minimum pressure of 1 bar*. What this level is should be specified in your contract.

* Some authourities seem to be able to get away with providing around 0.8 bar.