Water pressure problem with shower and basin tap

Dear All,
I recently had a new bathroom suite installed in my house (actually, a rece ntly acquired house for rental). For information, the area has soft water a nd the heating system is a straightforward old fashioned gravity fed system with hot water cylinder.
Prior to the new installation, the water pressure for the old thermostatic shower valve seemed adequate to provide a decently powerful spray and so I dismissed the notion of fitting a pump to power the thing. However, the new shower valve (Victoria Plumb's "Minimalist" model, see http://www.victoria plumb.com/Showers/Mixer-Shower-Valves/Minimalist-Dual-Exposed-Bottom-Outlet _894.html) seems to provide a very feeble flow. It's barely able to generat e a spray from the (also new) handset, being more of a lively dribble.
Being rather busy before the work was done, I didn't get round to noting th e arrangement of the plumbing to the bathroom and so I cannot be sure wheth er any major changes have occurred from the previous set up (which worked t o a satisfactory degree).
The plumbing now is as follows:
22mm hot outlet from cylinder feeding the bath hot tap and branching to 2x 15mm for basin hot and shower hot (ball valve fitted on each 15mm branch).
22mm cold feed from loft cold water, with same arrangement as above, but to cold outlets.
The bath taps run freely; a really good, strong flow. The basin cold tap ru ns freely, too. The basin hot is a weak flow and the shower is weak on hot or cold independently, or a mixture of both.
To add a variable into the mix, I looked at the loft cold water tank and th e cover (wooden board) is a mess (fragmented/rotten) and there are polystyr ene beads all over the place (insulation remnants, I presume). In the same loft space, there is also a huge wasps' nest that I think is disused (no bu zzing/critters). If someone had the nest treated at some point in the past, I guess that a number of bugs could have fallen into the tank.
So, what I'm wondering is what is the best place to start in looking to fix the problem? It seems to me that it might be:
i) Plumbing layout is now different than before, restricting the flow ii) New shower valve/hose/handset is restrictive compared to the old one iii) Partial blockage caused by debris having entered the loft water tank
The weak flow from the basin hot tap, but not cold, suggests to me that the plumbing is not the main problem. The water that supplies the basin cold t ap runs from the same loft tank and through the same 15mm plumbing arrangem ent as the basin hot tap (admittedly, without the intervening hot water cyl inder). My first thought, then, is to detach the shower valve and see how fast the water flows from the pipe stubs. At the same time, I can also examine the v alve to see whether any crap has found its way in there. Once this angle ha s been investigated, I would intend to head up to the loft to clean up the tank and fit a proper lid.
Does this sound like the correct and logical way to proceed?
Thanks in advance,
Jim.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What kind of ball valves have you got? Are they full bore (generally have a big lever to actuate) or are they more like these isolating valves? http://www.ebay.co.uk/itm/2-x-15mm-Isolating-Ball-Valve-Chrome-Compression-Fittings-A8ND-/370815694304
If it's the latter then they will grossly restrict flow, particularly in a gravity system. There *could* be crud in the pipes but my money will be on it being the fact that the new shower valve is designed to work with mains pressure water. Gravity fed mixer valves are harder to come by.
Tim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/08/2013 13:55, Tim+ wrote:
There *could* be crud in the pipes but my money will be on

That would be my guess. The spec says 0.1 bar minimum, which is about 1 metre head. Most taps/mixers these days are designed for high pressure systems, not gravity.
--
Dave - The Medway Handyman www.medwayhandyman.co.uk

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dear All,
I recently had a new bathroom suite installed in my house (actually, a recently acquired house for rental). For information, the area has soft water and the heating system is a straightforward old fashioned gravity fed system with hot water cylinder.
Prior to the new installation, the water pressure for the old thermostatic shower valve seemed adequate to provide a decently powerful spray and so I dismissed the notion of fitting a pump to power the thing. However, the new shower valve (Victoria Plumb's "Minimalist" model, see http://www.victoriaplumb.com/Showers/Mixer-Shower-Valves/Minimalist-Dual-Exposed-Bottom-Outlet_894.html ) seems to provide a very feeble flow. It's barely able to generate a spray from the (also new) handset, being more of a lively dribble.
Being rather busy before the work was done, I didn't get round to noting the arrangement of the plumbing to the bathroom and so I cannot be sure whether any major changes have occurred from the previous set up (which worked to a satisfactory degree).
The plumbing now is as follows:
22mm hot outlet from cylinder feeding the bath hot tap and branching to 2x 15mm for basin hot and shower hot (ball valve fitted on each 15mm branch).
22mm cold feed from loft cold water, with same arrangement as above, but to cold outlets.
The bath taps run freely; a really good, strong flow. The basin cold tap runs freely, too. The basin hot is a weak flow and the shower is weak on hot or cold independently, or a mixture of both.
To add a variable into the mix, I looked at the loft cold water tank and the cover (wooden board) is a mess (fragmented/rotten) and there are polystyrene beads all over the place (insulation remnants, I presume). In the same loft space, there is also a huge wasps' nest that I think is disused (no buzzing/critters). If someone had the nest treated at some point in the past, I guess that a number of bugs could have fallen into the tank.
So, what I'm wondering is what is the best place to start in looking to fix the problem? It seems to me that it might be:
i) Plumbing layout is now different than before, restricting the flow ii) New shower valve/hose/handset is restrictive compared to the old one iii) Partial blockage caused by debris having entered the loft water tank
The weak flow from the basin hot tap, but not cold, suggests to me that the plumbing is not the main problem. The water that supplies the basin cold tap runs from the same loft tank and through the same 15mm plumbing arrangement as the basin hot tap (admittedly, without the intervening hot water cylinder). My first thought, then, is to detach the shower valve and see how fast the water flows from the pipe stubs. At the same time, I can also examine the valve to see whether any crap has found its way in there. Once this angle has been investigated, I would intend to head up to the loft to clean up the tank and fit a proper lid.
Does this sound like the correct and logical way to proceed?
Thanks in advance,
You probably have a high pressure hand set. Nowadays most are. So your cheapest/lowest maintenence option is to get a low pressure one.
You might also find you have high pressure taps and shower mixer valve. Some claim to be suitable for both high & low pressure.
Or if you have those 1/4 turn isolating valves, many are not full bore (ie the hole through them is very small). They don't work well on low pressure systems (restrict the flow) You can get full bore ones.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have a similar problem to the OP. Old system was gravity 22mm from cold water tank & 22mm from (Warwick flange) HW cyl. No valves fitted. Used to fill a medium sized bath in 5-10mins. About 4m head. Recently installed bath/shower is pumped. Again 22mm throughout. Lever ball valves fitted to H&C supplies. Warwick flange still fitted. Ball valves 'look' like this: http://www.screwfix.com/p/full-bore-lever-ball-valve-22mm/30584 but I don't know if they are full bore. To fill a bath now takes 20-25 mins and shower performance isn't great.
Is it possible to tell the difference between full bore & restricted valves externally? Or should I drain down as required and dismantle? Valves, as ever, are in a hard to get-at place. Thanks, Nick.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Pumped? Through 22mm? Even a cheap pump should provide very adequate flow through metres of 15m plastic pipe, at least ours did. Got to be something else wrong.
I would guess it's down to the taps being overly restrictive.
Tim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


If the valve body is more or less the same size as the pipework, the hole through it is much smaller so causing a restriction. (BTW if the bore is not speciifed, it will be small). Often only 25% of the pipe size CSA. These are OK for mains pressure unless exceptionally low.
The full bore valve have a body signifacntly bigger than the pipework, cost more, and are specified as full bore. Use on low pressure sytems and heating sytems. And baths where you want them to fill as quick as possible. (Remembering that it only takes one valve in the line somewhere to f**k things up.)
All these 1/4 turn valved BTW are just cheap shite. Avoid wherever possible. Mostly you don't need them, what are stoptaps for?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 13/08/2013 07:39, harryagain wrote:

Indeed. Going from 10mm to 13mm almost doubles the area.
--
Dave - The Medway Handyman www.medwayhandyman.co.uk

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

well, by 69%, anyway.
--
From KT24

Using a RISC OS computer running v5.18
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, August 12, 2013 6:38:20 PM UTC+1, harry wrote:

ed

c

I

ew

Exposed-Bottom-Outlet_894.html)

the

er

a

x

.
to

hot

the

ene

ft

ix

he

tap

nt

e

the

e

Thanks to all for the suggestions.
It does seem that added systemic restrictions to flow are the problem, rath er than a blockage.
The shower head and hose were one aspect. In haste, I had bought an on-sale item from Victoria Plumb that would, no doubt, have been fine for mains pr essure or pumped. However, the 8mm bore of the hose and the high-pressure h ead markedly reduced the flow on my gravity system. Just replacing these fo r a 15mm bore hose and low pressure head made the shower almost acceptable. The el-cheapo ball valves were the remainder of the problem. Replacement wi th full-bore versions has seen the shower flow restored to its former glory .
Regards,
Jim.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 12/08/2013 13:34, Jim Walsh wrote:

Am I the only one thinking "airlock"?
Might be worth backfeeding mains cold water into the hot taps/shower to see if you can dislodge any bubbles.
Andy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, August 13, 2013 10:26:15 AM UTC+12, Vir Campestris wrote:

Don't do what I did to clear an airlock. I attached a large empty container to the tap and attached a vacuum cleaner to the container. I now recommend having two containers in series. I managed to dry out the vacuum cleaner! The airlock did get removed.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.