Mixer shower - nowater flow!!!

[Lynnoakwood]

Please can anyone help? We've just had a Coram shower pod installed, with a thermostatic bar mixer ... and there's a problem with the water flow, or lack of

When we turn the flow knob on nothing happens - it only works when we turn the temperature control round and round, and even then it takes ages to kick into life

Our plumber has fitted a valve on the pipe near the tank to stop air being sucked in, as he thought it was an airlock or something, but it's made no difference and he's puzzled too

Please can anyone advise what this is likely to be?????

 

[DP]

Mixer could be faulty, so could plumbing. Plumber being stuck is certainly not a good sign. But then again is he really a plumber or a simple handyman?

 

[Lynnoakwood]

Many thanks, DP - yes, he's actually a plumber, he's done it for 35 years, so I can't understand why he can't seem to sort it

There's a pump involved too, to boost the flow - could it be this as well? If we've just had a shower and try to turn it back on immediately then it comes on fine, but if there's a gap between one use and the next (which obviously there usually is) that's when it plays up - and the longer the gap since it was used, the longer it takes to jiggle it back into life

What frightens me is the thought of having to replace the mixer and it not working ... then replace the pump and it not working ... and on and on ...

So sorry about this, but we're getting REALLY frustrated!!!!

Cheers,
Lynn

 

[seco services]

Has he checked all the filters and nrv's are free ?

 

[Lynnoakwood]

Many thanks for everyone's advice so far, but now I'm even more confused ...

The plumber came and said the bar mixer and pump are OK but that there's a problem with low hot water pressure in the house; it's not enough to make the pump start working. The boiler's in the kitchen and the pipe carrying the heated water goes to the tank in the airing cupboard in the bedroom above. His spur to carry hot water to the new shower pump has also been put in the airing cupboard, running from this rising hot water pipe at about waist height. The shower pump is in there too, just below the ceiling

He's saying that on Wednesday he needs to re-fix the spur higher to increase the pressure, and that for now, if we switch the shower on with the handset lower down it will work ... but it doesn't. So can the water pressure be increased this way? Does this make anjy sense? What I especially can't understand is that we had a power shower before we changed to the cubicle with the mixer, and there was never a problem with the pressure then - why is there now?

Above all, I'm terrified he'll say we can't have a mixer shower at all, though I can't see why not as everyone else has them round here. We spent a vicious amount of money on a leakproof cubicle and I'm frightened to death it's not going to work

I'm really no expert as I'm sure you can tell - please, please can anyone put my mind at rest???!!!!!

 

[BathClick]

Hi again,

That doesn't sound right to me, so here goes

I am assuming that you've got a cold water tank in your loft and a hot water cylinder, the hot water pressure coming from the cylinder is determined by the difference in height between the hot water cylinder and the cold water header tank i.e the amount of gravity acting on the cold water from the header tank to push the hot water out of the cylinder.

Is your shower head in it's normal operational position and the pipe work feeding the shower head below the level of the cold water tank?

if so the hot water supply for your shower should be taken directly from the cylinder via a tee before hot water feed for rest of your house or an essex boss directly into the cylinder itself. The pump can be positioned on the floor of your cylinder cupboard, moving the position of tapping upwards will no effect on the pressure arriving at the pump.

If the position of your shower head or the pipe work supplying it is above the cold water tank or even level with it you need a negative head pump in order to pump the water beyond the point at which gravity is effective.

I hope this helps, sorry it's so technical there isn't really an easy way to explain it, but I do think you should get a second opinion.

Regards
BathClick

 

[Lynnoakwood]

Is your shower head in it's normal operational position and the pipe work feeding the shower head below the level of the cold water tank?


Yes, the cold tank is in the roof so the shower head, the hot water tank and all the pipes are below it ... this is why I can't understand what he's on about, saying that there's not enough hot pressure going into the pump, and he has to move the "tapping" as you called it. Especially, like I said, as the power shower was perfectly okay ... how could this have been if there wasn't any proper hot water pressure?

It's also what I meant when I said I was worried about it getting done at all - if moving the tapping won't improve the pressure, then how the heck will the pump EVER be made to work???

Can you make any sense of this???!!!![/b][/u]

 

[BathClick]

Hi

Could you post the make and model number of your pump? if I know this I can check on the minimum flow rate required.

It would also be worth running your shower into a bucket (without the pump running) for 1 minute and then measuring the water to find out what the natural flow rate is L/Min.

 

[Lynnoakwood]

It's from Wickes and I've copied and pasted the info below - hope it helps??

Yes, my hubby ran it out of interest to find the flow and it's about 15 litres a minute

Hoping to hear from you - and we really, really appreciate this, by the way

1.5 Bar Twin Impeller Shower Pump

Product Code: 200206

Flow Rate: 5 - 50 litres per minute
Width: 12cm
Length: 30cm
Pressure: 1.5 Bar
Height: 18.5cm
Inlet Size: 22mm
Weight: 2.9 kg

Suitable for single shower mixer valve with multi-function head or single basic bathroom suite.
Suitable for use with gravity hot and cold water system.
Not suitable for use with combination boilers or mains pressure hot water systems
Increases effective head pressure by equivalent of up to 15m
Pumps 5 - 20 litres/minute (recommended). Maximum flow rate of 50 litres/minute to boost flow & pressure

 

[JohnD]

15 litres per minute is a pretty good shower. Is that without the pump?

 

[Lynnoakwood]

Hi again,

So sorry, my fault ... the 15 litres a minute flow rate was the old power shower. I've just got a bucket and measured the flow of the new mixer one, and it's 6 litres a minute with the pump running, when it eventually does - obviously until the pump starts there's no water coming out of the shower head at all

This flow rate is fine by us - the old one used to nearly blast us out of the enclosure (!!) The problem is that the pump just won't come on as it should when we turn the flow knob - the temperature knob has to be fiddled back and forth for ages to make it start pumping and flowing. This is what our plumber doesn't seem able to fix, though now he's saying the hot water pressure going into the pump isn't enough to make the pump start

Frankly we can't understand a word of what he's saying - can you make any sense of this at all???

 

[BathClick]

Hi,

I've had a look at the pump specs and wikes say it will operate on a minimum natural flow rate of 0.5 L/m I find hard to belive that flow rate could be causing the issue.
Please take a look at this pdf
http://www.stuart-turner.co.uk/media/4336-Showermate-Standard-Single-and-Twin.pdf

It's for a Stuart Turner pump but the installation is the same as the pump you have and it has good diagrams. Have a look at Fig.7 I think this is the most like your installation, you will notice the u-bend in the hot pipe serving the pump check in your airing cupboard and make sure your plumber has put one of these anti gravity loops in the hot supply to the pump.

If this loop isn't present I would bet this is the problem as this means air will vent from the cylinder to the pump instead of up the expansion pipe.

Failing that it sounds like a faulty pump/flow switch I don't think you'll get spares for this pump so it will probably have to be a new unit. I know they're a lot more money than the wikes unit but a Stuart Turner shower mate or monsoon would be my recommendation.

Thanks
BathClick

 

[Lynnoakwood]

Hi Bathclick,

Well, I've poked around in the airing cupboard, and no, there definitely isn't any U type bend in the plastic pipework supplying the hot water to the pump ... so I'll definitely mention this on Wednesday when this blasted guy comes again

I must admit I'm also a bit surprised that this new pipework supplying the pump has been attached to the "upwards" pipe which brings the hot water from our kitchen boiler to the cylinder ... on all the diagrams, the pipework seems to be attached either to the tank itself, or to one of the pipes coming OUT of the tank, not going into it???

Anyway, it really is beginning to look as if it might be an installation issue - heaven forbid that we've got to start exchanging the wretched pump or mixer valve, we're about sick of this already and it's only your very generous help which is keeping us sane right now!!!

 

[DP]

OP, why are you worried that the shower or whatever will need to be replaced? You have asked a plumber who you say has been plumbing for 35 years (surprised plastic pipe is the material of choice). Let him sort it out.

Does the pump feed other taps? If yes, do you get good flow of hot water there?

 

[Lynnoakwood]

OP, why are you worried that the shower or whatever will need to be replaced? Let him sort it out

You're right, of course, DP - but I must admit I'm starting to wonder about this guy, frankly!!!

The pump operates the shower but nothing else, and the hot water flow to the house taps is fine - obviously not as strong as the cold water, but perfectly acceptable