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Gravity Feed Pump Pulsating for First Couple of Minutes

Postby Farooko » Tue Jul 31, 2018 9:10 am

Hi All

Another gravity feed pump related query! I have this pump installed in the loft for both hot and cold water. It was running fine and suddenly it started pulsating (i.e. it switches off and on) for first couple of minute and than it runs fine. It is only feeding to the shower upstairs. I have tried switching it off and run the shower for a while to remove any air locks (not even sure if there is an air lock or is it going to help), also tried lowering the shower head and see if it makes a difference, but nothing.

Help please :)
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Simply Build It

Postby Farooko » Wed Aug 08, 2018 6:31 am


I have an issue with the shower which is driving me mad and hopefully someone would be able to point me in the direction. Few weeks ago my shower started to pulsate a bit (water coming out slow than fast for first couple of seconds). Over the period of couple of weeks, it has gone really worse and pulsating now for first 3 or 4 minutes.

In terms of setup, I got my cold water tank in the loft and below that, I got my immersion heater tank, then I got a twin impeller gravity fed pump which only connects to the shower. I can hear the pump pulsate as well.

When this problem started, I tried leaving the shower head on the floor to see if it makes any difference, but nothing. Now, when the problem has gone even worse, I tried it again i.e. leaving the shower on the floor. This does make a bit of difference i.e. it does pulsate for couple of minutes and then a steady flow unlike pulsating for 3-4 mins and than steady flow.

I was initially thinking that it could be a shower head or the shower hose. So, last nite, I took the shower hose off and turned the tap on, but it was doing the same thing. This means the hose and shower head are fine?

I also noticed that hot water flow in all the taps is not as fast as the cold water.

Please point me in the rite direction so I can have my shower in peace!
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Postby thedoctor » Mon Aug 13, 2018 12:53 pm


Without being able to lok at the setup it's a bit hard to diagnose. A few possible causes could be an air lock in the pump or even the pump itself is faulty.

Unfortunately your best bet is to get a plumber in to take a look

Kind Regards
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