Pump Query and a horrible feeling

[PlumbingNewb]

Hi

Our mixer shower has always run slowly with very low pressure (taps seem fine). We asked around and one electrician suggested a dual pump but also told us that this was really work for a plumber. So, we contacted a plumber, told him what the electrian had said and he came out to fit the pump. Its a Salamander CT55 (unsure if more information is needed than that) and it is hooked to our hot water immersion heater (we don't have gas).

Couple of issues:

1. Its extremely noisy - anyone got tips for reducing this? It's acually waking people up in the house!
2. Using the shower, if I turn on the hot water and then the cold, it runs red hot (like the cold tap isnt even on). This is the case even if I turn the hot tap on just a small amount. If I turn on the cold tap first then the hot tap, no hot water fill flow at all and the pump doesnt engage (trust me, I would hear it!)
3. After a short while of running both taps together (hot on first then cold), turning the hot tap off means that I get some warm water - assuming this is hot water that had run backwards up the cold pipe?

My real questions are:
1. Should we have had this single pump fitted or was there a better solution?
2. What on earth is going on with what now appears to be mutually exclusive shower taps? Sink taps will run happily with hot and cold together mixing to make warm, but the bath taps will not (its one or the other).
3. How can we fix it.

Any help VERY much appreciated because at the moment this was £230 down the toilet, so to speak!

 

[SimonG]

Was it a plumber that installed it?

Has the hot feed been taken from the cylinder as close as possible?

Is the pump in the airing cupboard?

Has the 'plumber' provided a tanked cold feed to the shower or tied it into the mains?

Any pictures?

 

[iain85]

Just googled the ct55. It is a single pump impeller so by the sounds of it the hot water is provided of the pump and the cold is from the header tank.
Sounds like the hot water is pushing back on the cold water supply and to overcome this you really need a twin impeller pump to have equal pressure (cold water pumped as well ). Really the plumber should of known this, and at the very least hasn't checked it after he installed it so I would call him back.

 

[SimonG]

If the ct55 is single impeller then my moneys on tanked hot and mains cold.

 

[PlumbingNewb]

Hi

Thanks for the replies. Some answers here:

1. It was a plumber, at least he advertises as such and thats what his invoice says!
2. The pump is situated right next to the hot tank - there is a pipe from the hot tank into the pump, and another pipe out of the pump which disappears below the floor. The cold pipes weren't touched. Assuming that this answers "Has the 'plumber' provided a tanked cold feed to the shower or tied it into the mains?"?

We did speak to him and he suggested he might need to fit some non-return valve(?) but I really dont understand why turning the hot tap stops all the cold water, and vice-versa. This happens from the bath taps as well as the shower (which comes from the same taps), but isnt a problem with the sink taps which are in the same room.

 

[tom609]

as previously a twin impeller pump should be installed what shower make and model

 

[iain85]

Yes, It answers question 2 in the negative.

Basically because the hot water is a higher pressure, it is forcing the cold back down the cold water supply at the point of the 2 mixing. The none return valve will not solve this as it will still not allow the water through.

I suggest a 2nd local opinion.

 

[Plumber live]

Get said plumber back, He's messed up the install. Although probably better to call different plumber . Who knows what there doing.

 

[Billy Bob Bob]

sounds like your plumbers a numpty

 

[PlumbingNewb]

So basically, hot is now too powerful and is stopping cold from pouring in for mixing? I think we'll have to get him back - I can see this being an uphill struggle to get him to do it properly (i.e. swap the single for the double)