Salamander Shower Pump Problem. (Again!)

[conny]

Hi all. Fitted a replacement Salamander shower pump, (CT75X 250w), just over 12 months ago.

It replaced a CT50 which had burnt out before we rented the property, (didn't find out till after moving in and landlord paid for replacement pump). We have often had problems with air locks due to the run of the pipe work and on occasion I have had to bypass the pump switches and 'force purge' the system to remove the air.

Just returned from a 10 day holiday and now can't get the pump to operate at all. Have tried the by pass method and even fitted a new capacitor but the pump will not even attempt to start. We have a small trickle at the shower head but not enough to have a proper shower. Pump is situated on the floor of the airing cupboard next to the hot water tank. Cold water tank is in the loft about 8' higher,(to the base of the cold tank). Cold water is fed from the loft to the pump, from the pump back up into the loft where it then runs across for about 12'-15' before dropping down into a stud wall cavity to the back of the mixer valve. From the mixer valve it is then piped back up to ceiling height to an overhead outlet plate. Hot water runs the same path from the pump to the shower head.

As I am not in work for another week I have no test equipment here apart from a multimeter. (Have checked the fuse and that there is a 230v supply to the socket.)
Can anyone give me any ideas what the problem may be this time and if, in their opinion, the pump is adequate for this length of pipe run. If not adequate then what size would you suggest?

Sorry for long post but have tried to give as much info as possible. All pipework is 15mm copper with the exception of the 15mm flexi tubes to the pump.

 

[leakydave]

Can you use a wet/dry vac on the shower hose to get the water moving?

 

[conny]

Its running through at 'gravity' rate at the moment and don't have a wet/dry vac unfortunately.

 

[leakydave]

Is there any way to eliminate trapped air at the high points of your pipework? My guess is you have an air lock stopping the water flowing properly.

 

[conny]

In the past I have eliminated the air lock by removing the switch lead and connecting the mains live to the switch terminal, this then allowed the pump to start directly and force the water through eliminating the air lock in the process. Now when I try it the pump won't start using this method.

Would a negative head pump be of any use in this arrangement?

 

[Madrab]

If you aren't able to run the pump by bypassing the switched connection then it sounds like the pump has either burnt out again or seized.
Given you have replaced the capacitor are you able to manually spin the impeller?

I'd be looking at the pipe runs etc and looking to see if a better design could be incorporated. If not a universal pump may be more suitable.

 

[conny]

Thanks Rob. I've now fitted a new pump, (fully working), and will test the old one when I get back to work. (Armature winder by trade so have the necessary equipment in work). Had a quick look at the old one and the impeller turns with the aid of a slim screwdriver so suspect it is either scaled around the switches or burnt out.

The pipe run is a nightmare! Down from the c/w tank in the loft, back up again to the loft, across the loft for about 12' then right angled for another 6'-8' before dropping down a wall cavity to the mixer valve, (encased on both sides by tiled walls), then up to the overhead shower outlet. The pipes in the loft do not lay flat but actually curve up in an arc about 9" from the loft floor before dropping into the void. If it was my own house I would rip the whole lot out and re-route everything under the floorboards but as it is rented property its not my choice.

 

[Madrab]

One thing Id maybe consider then conny is getting a handful of nail in pipe clips and at least clipping the pipe flat to minimise the chance of airlocks.

 

[conny]

The problem is Rob, they are arched to cross over other pipes in the loft. The whole plumbing system is unbelievable with pipework to the radiators buried in the plaster and not even rising vertically from the valves. They come back across the radiators at approximately 45 degrees to meet around the middle and then go vertically up in the wall to God knows where. If we have the heating on you can trace the pipe runs by feeling the walls!

Hopefully we will be moving on in October and believe me, I will have a lot of questions to ask any new landlord we may speak to!