New mono mixer tap fitted, hot water flow is slow!

[Ben-gee]

In post #1 you said the tap was suitable for 0.1 bar to 0.5 bar - this is an unusual range to be stated.

Are you sure it is not 1 bar to 5 bar?

5 bar is a common maximum pressure rating.

I suspect you have a high pressure tap.

There are lots of low pressure mono taps out there that perform satisfactorily at 0.2 bar, which is probably the pressure you have.

 

[John.g]

Again, "The cold water running flow is absolutely fine, no problem whatsoever." (post #1), the crux of the problem?
The tests I carried out, admittedly on a two tap mixer at a 0.6bar (downstairs) head was exactly 2.62LPM (each) with the 6mm tails attached and 4.0LPM with tails detached, probably a hi pressure tap, these 1/4 turn taps do have very narrow outlet slots, the main port is I think ~ 10.5MM.
Based on the above, would expect only ~ 1.5LPM upstairs at a 0.2bar head.

 

[Koko88]

In post #1 you said the tap was suitable for 0.1 bar to 0.5 bar - this is an unusual range to be stated.

Are you sure it is not 1 bar to 5 bar?

5 bar is a common maximum pressure rating.

I suspect you have a high pressure tap.

There are lots of low pressure mono taps out there that perform satisfactorily at 0.2 bar, which is probably the pressure you have.

In post #1 you said the tap was suitable for 0.1 bar to 0.5 bar - this is an unusual range to be stated.

Are you sure it is not 1 bar to 5 bar?

5 bar is a common maximum pressure rating.

I suspect you have a high pressure tap.

There are lots of low pressure mono taps out there that perform satisfactorily at 0.2 bar, which is probably the pressure you have.

 

[Koko88]

Just checked the specification, instruction leaflet on the mono mixer taps, it’s compatible with both low & high pressure, 0.1 to 5 bar, so my mistake when I said 0.1 to 0.5 bar!

 

[Koko88]

But, the cold water flow is/as was? greater than the HW flow?, if so can you just measure the flow from each when detached from the mixer tap just in case there is some restriction in the HW supply.

 

[Koko88]

I have tested the flow, detached both the hot & cold supply pipes from the new mono mixer

The hot water flow is fine, even reconnected it back to the old mono mixer, the hot water flow is a lot stronger than the new mono mixer as previously stated.

 

[John.g]

Can't find your txt with above,

Got it now, can you measure the exact flowrates now from both the hot and cold attached to the Tap (normal)

 

[Koko88]

What is measuring the exact flow rates on hot and cold going to help/solve the problem?

Apart from knowing the flow rates figures/specs & etc, the hot water flow still going remain the same, regardless?

I am thinking of trying another set of mono mixer taps with 2 individual lever, hot & cold, compression valve type than ceramic to see if there’s any difference.

 

[Ben-gee]

The best flow will come from a compression valve tap.
I have seen a cut away mono mixer with “lift and turn” cartridge- the pathway from where the tails screwed in to the underside of the cartridge was a 2mm channel through the brass.

 

[John.g]

What is measuring the exact flow rates on hot and cold going to help/solve the problem?

Apart from knowing the flow rates figures/specs & etc, the hot water flow still going remain the same, regardless?

I am thinking of trying another set of mono mixer taps with 2 individual lever, hot & cold, compression valve type than ceramic to see if there’s any difference.

IF, as you said originally, that the cold flow is absolutely fine with the new Tap but the hot is not fine then ( and you have proved that there is no restriction in the supply) to me that points to a faulty Tap which may be replaced FOC if still within warranty and knowing the two flowrates will strengthen your claim, Now, I don't know what absolutely fine means in your book but I have a bathroom basin tap fed from 2 X 1/4 turn taps which I presume are of the cartridge type and from the CWST head of ~ 0.2/0.25bar gives a hot flowrate of 4.04LPM and a cold flowrate of 4.48LPM, both fine by me, you can compare your cold flowrate with this, if you wish, and if happy with it and if you are happy with the single lever Tap then I would look at replacing it with a similar type, hopefully, FOC.

The above does show that there is a huge difference in LP and HP designed Taps as the old 2 tap mixer I tested a few days ago will only flow ~ 1.5LPM at a 0.2bar head, both Hot and Cold.

 

[Koko88]

IF, as you said originally, that the cold flow is absolutely fine with the new Tap but the hot is not fine then ( and you have proved that there is no restriction in the supply) to me that points to a faulty Tap which may be replaced FOC if still within warranty and knowing the two flowrates will strengthen your claim, Now, I don't know what absolutely fine means in your book but I have a bathroom basin tap fed from 2 X 1/4 turn taps which I presume are of the cartridge type and from the CWST head of ~ 0.2/0.25bar gives a hot flowrate of 4.04LPM and a cold flowrate of 4.48LPM, both fine by me, you can compare your cold flowrate with this, if you wish, and if happy with it and if you are happy with the single lever Tap then I would look at replacing it with a similar type, hopefully, FOC.

The above does show that there is a huge difference in LP and HP designed Taps as the old 2 tap mixer I tested a few days ago will only flow ~ 1.5LPM at a 0.2bar head, both Hot and Cold.

I am going to take the mono mixer, single lever back to Screwfix later and swap it for another mono mixer with 2 lever/heads, hot & cold, compression valve type.

Have to wait and see if there’s any improvement!

 

[Koko88]

I am going to take the mono mixer, single lever back to Screwfix later and swap it for another mono mixer with 2 lever/heads, hot & cold, compression valve type.

Have to wait and see if there’s any improvement!

 

[Koko88]

Went back to Screwfix, exchanged the single lever type mono mixer for the 2 head type, compression valve mono mixer taps & fitted them to the new basin yesterday.

The hot water flow is now back to normal just like it use to be!

It’s either the compression valves or having 2 tap heads made all the difference or a combination of both!

The only downside is the returned single lever mono mixer taps looks more modern, slicker in design & looks!

 

[Ben-gee]

It’s the compression valves, see post #24, this is not new to us!

 

[John.g]

It would be interesting to compare the new 2 Tap compression type flowrates with the 4/4.5 LPM from my upstairs 2 Tap 1/4 turn type.