Power Shower Flow Issues

[bjblackmore]

Hi,

We have 2 power showers in our system, one in our en-suite and one in the family bathroom, which use a power shower pump located in the airing cupboard, along with the hot water tank/immersion heater, and a cold water tank in the loft, which I assume is for pressure (there is also a smaller header tank for the central heating). Until recently were both power showers were working fine. However due to the previous owners doing a botch job on the en-suite shower enclosure (not tanking/sealing the pasterboard or using waterproof tile adhesive/grout), we've had to gut the entire room, which meant using the family bathroom for showering, which for a week or so, was fine.

During the gutting of the en-suite we found there were no isolators on the hot & cold sink taps, so we decided to install some. To do this, I initially tried to turn the stopcock off by hand, but found it had seized, so tried to drain the cold water tank in the loft, and lift the ballcock arm to stop it filling, only for the ballcock arm to snap off as it was so corroded. After replacing with a new ballcock from Wickes, and using some WD40 + a proper universal stopcock key, I was able to turn off the main stopcock.

Once I replaced the ballcock, and fitted the isolators to the en-suite taps, I turned the stopcock back on, and let the cold water tank fill, adjusting the ballcock to the same level as before. However, since then, the power shower in the family bathroom seem to be having issues with the flow. Initially I thought it was the shower pump, but this in only 1 year old, and if you hold the shower below waist height, it works fine, but if you lift the shower to head level, the shower pump cuts out and the flow stops. To me, this appears to be a pressure issue. I've checked the stopcock is fully open, and have adjusted the ballcock in the cold water tank, so it now fills 2" above the level previously, but the shower still cuts out.

I'm not sure if this definitely is an issue with the pressure, if so how to resolve, or if it's an issue with the pump! As I said, we were using the family bathroom shower for a week before, and it was fine. It's only been since we turned the water off & fitted the isolators in the en-suite!

Any help or advice would be appreciated!

Ben

 

[stem]

The pressure is produced by the shower pump, but the header tank needs to give a high flow rate into the pump. It is possible that you have restricted the flow during your refurbishment.

If the header tank remains filled when the shower is used, then there's no problem there, and the main supply is keeping up with demand. The fact that the other shower works OK suggests this is the case. (I'm assuming that they use the same pump)

Whilst you were doing the work, have you made any changes to the en-suite shower pipes? for example reduced their diameter, or fitted unsuitable manual isolation valves? The isolation valves on a shower pump should be full bore when open. Most aren't and have a considerable flow restriction.

 

[St0rmer66]

Think stem might be right... Most normal isolation valves only have about 8mm bore size. You need to specify that you want (slightly more expensive) full bore isolation valves when you buy them.

 

[bjblackmore]

Hi,

Thanks for the replies!

The new isolators were only fitted on the sink taps in the en-suite where we're doing the work. The flow issue is with the power shower in the family bathroom, which we're using while the en-suite is being done. It was working fine before the stopcock was shut off and/or the tank was drained, to allow me to fit the isolators in the other bathroom. There hasn't been any isolators added, or other changes made between the power shower & shower pump, or shower pump and the hot water tank/immersion heater, and cold water tank in the loft! A quick drawing of the system below, not exactly correct, but near enough!

View media item 78208
I wondering if some crap from with in the tank got sucked down the pipe, and into the pump and is restricting the flow, or something. Although there is no sludge in the tank, there is a fair bit of limescale around the edges, and on the bottom of the tank.

 

[longdogs]

Check the pump filters for cr*p and try running the shower with the pump switched off.

 

[St0rmer66]

Any bleed vents in the loft you can open? Looks like a long horizontal run.

 

[bjblackmore]

Hi,

I disconnected botht he hot/cold input & output and checked for crap in there, but found nothing.

The horizantal run isn't as long as it looks in my pic, it's not really to scale, and the tank is a bit more to the left than in the pic. But there are no bleed vents, it's all speed fit pipes.

Having checked again last night, I'm begining to think it's the termostatic shower mixer in the family bathroom that might be the issue. I took 3 videos (embeded below), the first is the offending shower, (the video is shorter than I actually took, bluetoothing it to my PC for upload seemed to corrupt the file, it was 37 seconds long, not 12 originally! I can re-take when I get home later).



This is a video of the pump when the family bathroom shower is on:



And we managed to get the knobs & shower hose on the new shower in the en-suite, and tested, and this appears to work OK, the pump doesn't make any noise or cut out, and the flow seems OK. So I don't think it's an issue with pump, tank or pressure! It has to be the shower mixer?

 

[bjblackmore]

Managed to get a better video at lunchtime! You can see it struggling with the flow, then when you turn the tap the other way the flow increases for a bit, but then starts cutting out again!

 

[bjblackmore]

Have ordered a new shower mixer (bargain £30 down from £60), which should arrive by Wednesday. Will fit it, and see if this resolves the issue.

 

[theprinceofdarkness]

if you live in a hard water area, the thermostat area of the mixer can get filled with lime scale and needs cleaning. the other thing I was going to say was to set the temperature to min, and time the shower to fill a bucket, repeat when temp is set to hot. This is to see if its one or both pipes that seem to be blocked.
Showers need about 50/50 hot/cold water, so if hot is blocked, thermostat will select max hot/min cold to balance temperature, which will reduce the flow.
Frank

 

[St0rmer66]

if you live in a hard water area, the thermostat area of the mixer can get filled with lime scale and needs cleaning. the other thing I was going to say was to set the temperature to min, and time the shower to fill a bucket, repeat when temp is set to hot. This is to see if its one or both pipes that seem to be blocked.
Showers need about 50/50 hot/cold water, so if hot is blocked, thermostat will select max hot/min cold to balance temperature, which will reduce the flow.
Frank

Think it's more like 2/3 hot to 1/3 cold (depending on temps) but yes you're right otherwise.

 

[bjblackmore]

Well, the new thermostat arrived today. Quick job to fit it, tested, and it works perfectly!

Looking at the old thermostat, both inlets have a filter in the pipe. The cold inlet was bunged up with what looked like fine hair & some limescale. I don't think it was hair, maybe very fine filings or something.

The new one is fitted, and all working, and the old one is probably furred up on the inside, so I won't bother swapping it back, especially as it's less than £30.

 

[St0rmer66]

Glad to hear of a nice result . Do you have any kind of limescale prevention in the house or is it not a bad area? How old was the shower? Could be worth buying another while they're so cheap for future use...

 

[bjblackmore]

Well its Swindon, South West, so fairly hard water, we get a fair bit of build up in the kettle. No prevention at the moment, might be worth looking into at some point. However the filter wasn't blocked by much limescale, it was more this fibrous hair like stuff. Wish I'd taken a picture now, it would be like the stuff you'd get down the plug hole if you used hair clippers on very fine short hair! Only a small amount, and very fine, but enough that the entire filter on the cold inlet was blocked. And when I rubbed it between my fingers it disintegrated. Something must have been disturbed when emptying the cold water storage tank.

 

[bjblackmore]

Forgot to answer your other question on shower age!

I don't think it that old. We moved in last year, and this bathroom looks pretty new, nicely done, and quite modern. I'd say less than 5 years.