problems when using a Shower pump

Hi All,

I've had a mixer shower (Mira) installed now for a few years and found it to be very poor when it comes to the water pressure that comes out. I then purchased a power shower pump that delivers the hot & cold feeds under pressure. This worked great for the first 15-20 mins and then the water would go cold. When left to cool down the system would work once again.

The pump was sited 400mm below the cold water tank, the hot feed having been drawn from the lower floor hot water feed. The temperature for the hot water tank is set to 65 degress.

When the water tends to go cold you tend to hear the pump make a little more noise than normal. The pump is a variable speed, swin impeller design. Due to the hot water gravity feed I had to change the automatic flow control over to a switched pull cord following advice from the manufactures of the pump.

I'm now unsure as to the best course of action, i've been told that the pump may have to be at the same level as the hot water tank and I'm unsure if this is correct.

Any help would be of use please.

Sounds like the pump is sucking air in on the hot side. When this happens, what is the water level in the feed tank? Also what connection does the hot feed to the pump have to the cylinder? It should be a special flange of some sort.

Are you sure after 15-20 mins you haven't used up all the hot water and the pump is then drawing cold water.
The recovery time of the hot water supply may be the issue here.


Hope this helps.

Quote:
the hot feed having been drawn from the lower floor hot water feed.

Sounds like its not piped to the cylinder at all, in which case it will draw in air. Just like Chrisshut says.

Have a look at this it might shed some light on the problem.

http://www.bathroomexpress.co.uk/shop_tec_qtinstall.htm#siting

Hope this helps