Power shower stopped by probably and air lock

[cabbage]

I have a pumped (2bar) shower running from a conventional roof tank fed cylinder. The hot water take off is from a dedicated outlet about 6 inches down from the top of the cylinder. The pump is about 2 feet above the top of the cylinder. The roof tank is a good metre above the upstairs ceiling. Pipes run from the pump outlet by rising about a foot, running horisontal for about 15 feet and then down to the bristan mixer and diverter valve which feed a ceiling head and a flexible head. The fixed head is about 6 inches above the outlets of the pump.

It has all worked very well for 3 years but now the pump refuses to run for more than about 10 seconds before it stops, the water still comes through at reduced pressure.

I think the problem is probably air in the highest point of the pipework between the pump and the shower valve. I intend to split the pipes near to the pump outlets and let the air out but I want to prevent this happening again, preferably without having to do a huge re-plumbing job.

Having read quite a lot on the forum about shower air locks I am a bit confused....

Do I use
a. non return valves on the output side of the pump (between pump and shower valve) ?
b. do I put tees in both the hot and cold outlet pipes(with the branch rising vertically) and fit auto vents or some other kind of vents in the end of the branch?

Or do I do something else entirely.

Thanks

 

[PlumbBobBob]

lower the pump to the base of the hot water cylinder and just add a small amount of pipework.

 

[cabbage]

Thanks steve but I don't really have room for the pump at the bottom of the a/c as the tank nearly fills the space. It can't be collecting much air as it works for several years OK.

 

[Gray0689]

Your pump is probably done if it that age and was plumbed in a bad spot

 

[cabbage]

The pump does still pump water for the 10 secs and isn't any more noisy now than it was when installed.

 

[WHPES]

Have you cleaned out the filters on the pump recently?

Even if you can't get it level with the bottom of the cylinder, can you at least get it lower than it is now? Is there room for it under the bath?

 

[cabbage]

Hi
No I haven't yet cleaned the filters out, I was going to do that when I drained it all down but i thought that it might be wise to fit a couple of tees with auto air vents whist I had it drained down.

I'm still looking for someone to tell me if auto vents are the right item in this situation as I've also seen people say to fit Non Return Valves on the pump outlets as well.


Thanks

 

[Plumbstar Tom]

steer away from fitting it under the bath, the ventilation is not adequate for an air cooled motor

have you got and anti gravitstion loop to the pump due to its position?

 

[cabbage]

Hi
No I haven't got an anti-gravity loop but it wouldn't be too difficult to fit one if I understand correctly.
Can you confirm that I leave the cylinder flange and drop the pipe for about 200-300 mm then loop back up to the pump - using swept bends ??

Not sure what it actually does but I'm game to fit one !
Thanks

 

[cabbage]

Bob
I should have also asked, If I should put an air bleed valve of some sort at the highest point after the loop and before it enters the pump ?? Should this be manual valve or automatic ?
Thank