hot water vent pipe?

[daveth]

Hi chaps, total newbie here but hoping I can glean some knowledge. My problem is that occasionally my recently installed salamander shower pump cuts out - particularly when its very cold, and also it a bugger to get start up after the hot water system has been drained for any reason. im thinking air locks & maybe cavitation here?

The shower + pump are fitted in a loft conversion. (So hot water tank is on the 1st floor with shower + pump on the 2nd floor and cold water tank above that in the roof). The plumber who fitted it has gone out of business and my new plumber is trying to pick up the pieces but is unsure of the simplest solution.

Anyway my new plumber is proposing to relocate the pump from 2nd floor to 1st floor (next to the hot tank) & add a Warix flange to the hot tank feed.

However currently the hot water feed pipe to the pump is a combined feed + vent with the vent branching off at the highest point to the cold tank before the pump.

My plumber doesnt think that the combined pump feed/vent will work after the pump is moved and therefore a new vent circuit needs to be installed - a major job as the pipes were routed under the loft sloping roof ceiling during the loft coversion 1st fix....

He also considered a non vented hot water tank - but thats quite an expensive solution too

Question - can the hot water remain as a shared feed+vent after the water is pumped? Are there any other simple solutions without ripping out half my good ladies newly decorated loft conversion?

The pump works fine *most* of the time, so i really dont want to throw significant money at it, but equally whats the point of installing a ensuite shower if it cuts out at the worst moment when your eyes are full of shampoo...

Thanks in advance for any replies

 

[PlumbBobBob]

what about a negative head pump? then it could stay where it was a floor above the hot tank.

 

[Plumbstar Tom]

have you any piccys of where the hot connection is taken from?

Also go for a an essex flange rather than a warrix, its much better practice

 

[daveth]

Tom - heres a pic of the current hot tank outlet
https://picasaweb.google.com/114206526158951382656/Pipe?authkey=Gv1sRgCMLjtaqElpD0Og#
Theres currently no anti gravity loop fitted so I guess thats needed too?

Steve B - its not a negative head system (pump is way below cold tank) so is a negative head pump needed? Current pump is a salamander CT50 twin.

Sorry guys but Im still not clear if I can still use a shared hot feed/vent pipe if the vent branch is fitted AFTER the pump (rather than before it). The vent is for the whole hot water system, so if the pump isnt running can it still vent? Will the pumped (pressurised) water force the flow up the vent pipe as well as through the shower head?

Thanks again