Shower Pump

[Beena72]

I've just replaced a Showerforce Turbo pump which had given up the ghost, with a NewTeam Varispeed 50 (which New Team told me would just fit straight in, no plumbing mods required). The system is set up exactly like the diagrams show, with a head of about 2m for the cold water, and a head of about 1.2m for the hot (from the top of the HW cylinder to the base) or 2m if you count from the cold water tank). The shower head is about 1.5m above the pump.

The pump seems to turn on quite happily when the shower valve is opened, but sometimes is a bit half hearted, and I think only pumping cold water. If i hold the shower head down in the bath, as low as it will go, and then open the valve, it works propoerly, and pumps warm.

Are the two pumps activated independently? If so, is there anything i can do to improve hot water flow so it is enough to switch whatever switch needs switching inside the pump? Or am i doomed to a life of explaining to guests that they need to take the shower off the hook before starting the shower?

 

[meldrew's_mate]

Does it splutter just before starting to pump properly?

If so this sounds like you are collecting air in the hot water inlet pipework due to poor inlet design. If you re-read the MIs they will probably show diagrams and text designed to avoid trapping this "air" (airlocking in fact).

Can you re-feed the hot supply from a new flange cut into the side of the cylinder? Second best is to re-orientate the pipes so any air in them will rise and self vent.

Because the (assumption coming up) thermostatic shower valve senses cold flow on start-up it will run only hot flow initially, if you have no hot flow because of the airlock the pump won't start. Lowering the shower head allows hot to flow and the problem goes away with the expulsion of the air. (air + CO2 mix)

 

[Beena72]

thanks m_m.

It does occassionally splutter a bit, i've had a quick look at the tank to see if i can get an essex flange (or similar in), but there are no ready made holes, so it may be a job for a pro. The feed comes straight from the top in an equal tee with the main hot water, then there's a spur off for the vent pipe.

I'm still quite surprised that there is an airlock forming as the pump is effectively the lowest part of the system (bar the shower pipes running under the floor, but that's after the pump), and the rest of the system looks just like any diagrams i have been able to find on the web and the ones which the chap at NewTeam sent me (the pump was bought off fleabay)

There's no thermostat on the mixer valve, so it won't be that bit.

I'll have another look tonight at the pipework and see if there is any way i can sort the pipework between cylinder and pump to stop air getting in.

Thanks again.