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,