Low pressure on basin mixer tap (gravity system)

[rajeshk4u]

I have had my bathroom done. All looking good. However the bathroom Basin Mixer Tap has a low flow rate rate and low pressure. I never had this problem in the basin. I do have electric shower, as the pressure is not enough for a shower, but never issue with any basin taps. My old basinhad seperate hot and cold taps, which was connected directly via 15mm copper pipe.

However, this new basin mixer tap, I has two thin flexi pipes (hot & cold), which are 15mm connector, with flexi pipe is about 9mm. My basin has a single tap hole.

The builder is clueless about how tank based system work. I have a cold tank which is feeding into a hot water cylinder (immersion heater). I have 22mm pipe going to bath taps, which follow on and reduce to 15mm for the basin.

So far I have 4 possible thoughts:
1. Taps need adjusting? (there is a knob for hot and cold, but only need to 1/4 turn for on / off)
2. Airlock (though I have drained the hot & cold tank, but not sure the procedure for preventing air lock)
3. Taps not suitable for low pressure systems.
4. pipework slightly altered...

 

[WHPES]

3, Taps not suitable for low pressure systems

Most mixers are for modern type systems(i.e. combi / unvented)

Your best bet is to change to a low pressure mixer tap -these usually have separate knobs for hot and cold.

 

[BLOD]

my moneys on no. 3 as well !
most taps come with info on the minimum recommended pressure they can work at.

 

[rajeshk4u]

Thank you for your input... a few more questions:

1. If people are saying it is taps. If I went to a plumbing showroom, is it possible to distinguish if basin mixer taps are for high or low pressure systems? (what do I look for underneath). Any photos?

2. Other questions. My taps looks similar to Bristain Rio. The basin taps and the hot and cold taps are at 45Degrees. But they don't seem to operate on typical clockwise means closed. My brain has a trouble adjusting... how should I adjust my thinking?

3. As for bath taps, they are vertical up, look similar to the Bristain Rio bath taps. However, again but they dont seem to behave the conventional clockwise is off.

The builders says it must be a new fashion... but want to confirm this....

 

[BLOD]

Can you post a picture of your taps , and underneath them ?
As mentioned before nearly all taps come with printed info on what pressure they need to work ok.
It might be worth checking that how the taps have been connected, ie flexible hoses with kinks in ?

 

[royston]

option 3.

 

[rajeshk4u]

1. I went to the Plumbing Supplier where I bought the taps. He phone the dealer. He was told they are both LP and HP. However, there is NO documentation on the box. The taps are unbranded. They were in a white cloth bag with pull cord. Basin tap model no. DB404UK

2. Amazing, I can upload photo onto this forum.


3. You can see the flow, I am getting. Only one tap opened to max



3. These are the flexi under the basin. They are pretty thin. For comparison, I have put a normal 15mm flexi on the left. You can see the 15mm flexi is much thicker.



3. Underside of basin / tap tole.

 

[royston]

I take it these are the flexys that come with the taps ? Still say these taps arent suitable for gravity fed hot water systems. Whats the cold water pressure like through them, im presuming its mains fed ?

 

[rajeshk4u]

Yes, the flexis came with the basin mixer tap. The cold is via a tank. This is a single storey flat. So no loft.

 

[BLOD]

Surely the dealer could tell you what the minimum recommended head for the tap is ?
Take them back & get a refund - poor flow like that would drive me mad.

 

[WHPES]

If your cistern is only a couple of feet above the tap then even a tap suitable for gravity may struggle.

From my memory, most of the Pegler range can handle really low pressures.

The minimum for many gravity taps is 0.1 bar (approx 1 metre height between the tap and the cistern) and you maybe dont even have that much. This is why these old gravity hot water systems are getting to be a thing of the past now.

 

[rajeshk4u]

Fair enough about my old gravity hot water system.
But I was happy with the from my old basin. So why am I having problems with the mixer taps? Is it right to say that these basin mixer taps have very thin flexis?.

My original basin had two tap holes each with 15mm copper pipe connected directly. No flexies.

These thin flexis appear to be 8mm, which would explain my flow problem....

 

[royston]

Yes but if they are 8mm flexys that screw into the tap at 8mm then you carnt do anything about it, apart from get a tap that supplies 15mm flexys and runs on gravity low pressure systems.

 

[mickie]

those taps are half turn on/off arent they ? more than anything they just dont let enough water through for low pressure, that and the 8mm flexy and your service valve that also reduces the 15mm pipe right down.. buy a tap without the half turn and 15mm connections

 

[WHPES]

I have about 50cm head between my bathroom tap and the cistern. The bathroom tap is a single lever Pegler mixer and the hot flow is passable though not brilliant. I fitted it as my plans are to upgrade to thermal store and fit solar, but of course my own jobs come well at the back of the priority list!

 

[Plumbstar Tom]

Its probably copy of the bristan rio then making it cheaper so wont work as well on low pressure

You could try different flexis but I would say a different tap IMHO

 

[kay-jay]

i have fitted the same taps for my dad, he is on gravity system and they actually work fine if you change the flexi's for the copper type mono connectors.

 

[rajeshk4u]

Thank you for replies.

Mickie - can you get basin mixer taps with 15mm connection? Are they all standardised to use thin flexis?

kay say says: if you change the flexi's for the copper type mono connectors.

I am not sure what you mean by copper type mono connectors?

 

[PlumbBobBob]

some taps come with flexis some come with copper pipes to connect up to the feeds. one end is 15mm the other end screws into the base of the taps.