Shower pump stopping/starting, poor pressure

[terryplumb]

so is the pump only boosting the cold and not the hot water ?

 

[Johnny2R]

It doesn't appear to be reliably boosting either - it's stopping and starting, and when it runs, running with such low pressure I suspect it isn't actually doing its job at all. We have a Mira mixer shower with a single control for temperature, no means of setting the pressure separately (i.e., turn it a little bit, you get a full-pressure lukewarm shower, keep on turning and you get an increasingly hot shower at the same pressure). Now as I turn it, though, I get little surges as if the pump is actually working, which immediately stop.

It may be the case, of course, that the pump is actually failing. I don't think the 1.4 bar pump has been a current model for many years so I assume it was fitted at least 6-7 years ago, despite my vague memory of work being done more recently. Would the following pump work as a straight replacement for the Stuart Turner ShowerMate 1.4 bar twin pump? Seems to get good reviews and the price is good:

http://www.screwfix.com/p/salamander-pumps-ct50-xtra-regenerative-twin-shower-pump-1-5bar/20423

 

[terryplumb]

as it was all working fine before you changed ball cock and had the issue with loft insulation getting into the CWS tank ,I would be checking filters etc ,before shelling out on a new pump. with regard to draining , are there isolation valves on the loft tank outlet pipes ? there should at least be one on the cold feed to hot water cylinder ,but usually close to it ,not in loft. more pics of hot water cylinder and pipes to it ??

 

[Johnny2R]

as it was all working fine before you changed ball cock and had the issue with loft insulation getting into the CWS tank ,I would be checking filters etc ,before shelling out on a new pump.

Yes, not planning to replace the pump without first doing the filter checks. Not 100% sure loft insulation has got into the piping, as I only know some fell into the tank (from a badly made insulating cover), but as I can see some at the bottom of the tank still it may be that this was the only bit. If/when I drain the tank, I'll make sure to clear out the debris sitting at the bottom of it (chunks of limescale, for example). Just need to know how best to drain the tank.

 

[terryplumb]

if you don't want to waste your stored hot water ,isolate supply to loft tank ,by isolator if you have one ,or tie up the ball valve if you don't. electrically isolate the pump. isolate cold water supply to hot water cylinder .run the shower ,it will take a good while ,but it will eventually drain the loft tank. there are other ways but as you have told us you have little plumbing knowledge or experience ,the above will probably be easiest for you.

 

[Hugh Jaleak]

The shower may also benefit from a service, from that description. Mira are pretty good at doing spares and service kits for their products, essentially I think the internal design hasn't altered much over the years, so kits readily fit the older showers.

 

[Johnny2R]

No more really useful pictures possible, unfortunately. There is no isolation valve on the cold feed to the hot water cylinder. (However, next to the tank in the loft there is a smaller one which is presumably for the central heating, and there is an isolation valve on the cold feed coming from there). The pictures here show:

a) something coming off the cold feed to the cylinder, not sure what it is but don't think it's an isolation valve, and
b) the piping at the top of the cylinder. There is a horizontal pipe from the top which connects to a vertical pipe. I think the pipe going up from the connection goes to an overflow into the header tank, and down provides hot water to wherever - a pipe splits off that to provide the hot water feed to the shower pump.

 

[HERTS P&D]

Looks like that cylinder is due an up grade.

Andy

 

[Johnny2R]

The whole heating system will need an overhaul before too long. Boiler is ancient. Trying to get by until it's necessary, though.

 

[terryplumb]

on the second pic you posted this afternoon there is an isolation valve ,but pic does not show enough of the pipework to establish what it isolates .the pic showing the bottom end of the cold supply to cylinder is a drain off .if you follow that pipe up to loft and no isolator is fitted then just isolate the loft tank and turn on all hot taps and shower to drain out , ( if you decide you want to drain out). as said before electrics to pump should be isolated . you will of course lose all stored hot water ,so don't heat it before you drain.

 

[Johnny2R]

on the second pic you posted this afternoon there is an isolation valve ,but pic does not show enough of the pipework to establish what it isolates

The isolation valve in question is actually on a pipe which is capped off about 15cm above the valve. It looks like it originally went through to the bathroom and may be a relic of an earlier shower installation.

Tomorrow morning I'll be doing the drain-off and filter examination. Thanks, guys, for all the help. I know this is the sort of thing I really should leave to a plumber, but I like to have a go at things if I can. I normally hand over to the experts once I've made the situation worse, though...

 

[terryplumb]

good luck .

 

[AGAS]

don't you think it might be better to take a picture further away to include all pipework

plus the pump is getting on for 10 years old

 

[Johnny2R]

Here are some more images, although I suspect they won't reveal anything that helpful.

Anyway, I've done the drain-down and could not see a mesh filter as such on the cold inlet, having detached the pipe at the point it connects to the pump. There seemed to be a little limescale there, which I cleared as much as I could. I also blew back up the pipe (without detecting any blockage). But it hasn't made any difference to the shower, unfortunately. So, no progress, alas (although I have removed the debris from the loft tank).

So I think it's probably time for me to call the plumber. I asked about this pump earlier - http://www.screwfix.com/p/salamander-pumps-ct50-xtra-regenerative-twin-shower-pump-1-5bar/20423 - whether it could be used as a straight replacement for the Stuart Turner. Reviews suggest it's quiet, which is a plus. Also, it's 1.5 bar, close to the 1.4 bar one we have. As I mentioned earlier, there is no method of regulating the pressure at the shower itself, so we don't really want a pump which is just going to be blasting out the hot water faster, the existing one was fine when it worked.

 

[plumbingm8]

hi,

if you are looking to change the pump there are a few things you need to take into account, these being the shower head size to ensure you get the correct pressure, the highest point in the pipework ( to partially determine positive or negative) natural flow rate through the shower head ( as you need 2 litres per min hot or cold and 4 litres per min to start the pump- the other side of positive/negative head pump) and the outlets you are pumping to ( whole house pump or shower only) if you jump of the salamander website they have a pump selector or you can call there technical team on 0191 516 2002 and they should be able to help you with this.