Salamander Pump, (again!)

[conny]

Fitted a new shower pump the other month, (Salamander CT50-Extra), and everything was working fine.

Then we started getting a few hiccups. Sometimes we had to turn the shower on and off a few times before the pump would kick in. I think it was due to air in the system as the pipe run is ridiculous. Pump is next to the hot water cylinder in the airing cupboard. There is a feed from the cold water tank in the loft and another from the hot water cylinder in the cuoboard. From the outlet side of the pump the pipes run vertically back up into the loft, across the loft for about 10', rise up at 90 degrees for about 6" before turning at right angles for another 8' They then drop down a void between the main bathroom and en-suite, (which is where the shower is), terminating at a mixer valve buried in the wall with tiling on both sides so no easy access. From the mixer it rises to the type of square shower head that is fitted to a pipe that juts out the wall at right angles and then bends at 90 degrees for about 4"

We have been away for 10 days and on our return the pump wouldn't work. I by-passed the pressure switches to force any air out of the pipework and then re-connected the switches back into the circuit but the pump still won't start when I turn on the shower. Have tried this numerous times now and getting really frustrated. Have checked both pump outlets for debris or blockage and found nothing.

Can anyone shed any light on possible causes and remedies? Could I by-pass the pressure switches by fitting an external switched by-pass and turning it on when the shower has been turned on. If so, how long could I use this method without damaging the pump itself?
(The switches are by-passed by removing the switched live from the circuit board and connecting direct to the incoming live, as instructed by a plumber).

 

[Terry7556]

conny we swopped a boiler last month and the shower pump played up afterwards.on /off on/off somtimes 5 seconds, then 2 seconds.
the shower bar mixer was old but the head was 2 months old. took the head off and the pump never stopped.
the bloke wasnt having it.
went into his ensuite removed the head off his triton leccy shower.put it on his bar mixer shower and the pump didnt stop.
two days later ,phone call, shower not getting as hot as it used to before the boiler swop. pop round there and he is right but every hot tap in the house produced hot water.so i said cartridge is playing up but ill check the filters to eliminate them.nice and clean,.like the shower head answer he didnt seem to want to accept what i was saying.
i go home, take my £38 toolstation mixer off the wall, go back, swop it and it works, producing hot water and shower pump not pulsing.
so he replaced his mixer. not heard from him since but i think he still ignored my advice to clean the head in lemon juice, white vinegar or replace it
excuse the long post bud , may be way off the mark or you have already checked the shower and head. good luck with it

 

[conny]

Thanks Terence. Yep, have de-scaled the shower head and tried pump with head removed.
In the loft I have discovered that the hot supply runs aover the joists before turning up in a 90 degree bend before turning at right angles via an elbow. It then sweeps down towards the ceiling before disappearing down to the mixer.
I'm now wondering if I was to change the compression elbow for a tee joint and fitting a drain cock to the upper leg if I could use this as a sort of bleed valve to remove a possible air lock. What do you think? I don't want to fit an automatic bleed vent as I have heard these can actually draw air in to the pipe.

 

[Terry7556]

cant see how a thumb vent will do any harm
go for it, if nothing else it will eliminate a problem off the list

 

[stardanny]

How is the hot water connected to cylinder? Top, or side?

One job I did on a trial base, i fitted a tee on a high point of a long run of hot water pipe in loft that is prone to airlock with shower pump on, and ran from tee to over the cold water tank like a vent but with a anti gravity valve between above tee.
If there is air, anti gravity valve will open to let air out and water will remain at same level as cold water tank. If there is negative pressure eg shower pump running and sucking, anti gravity valve will stay shut and only the hot water run from cylinder. It worked as far as I know

Daniel.