Flow rate new kitchen install.

[Mdljk]

Hello again Guys

I've just had a new kitchen install. The fitters tapped into the overhead 15mm hot and cold that feeds the Utility Room 3.0m further on. The hot flow rate in the Utility Room (Monobloc taps) is 9.5 litres/min. In the new kitchen monobloc the flow rate is 4.5 litres/min, less than half of that in the Utility Room further along the supply pioes overhead. The combined hot and cold flow rate in the Kitchen is 14litres/min and in the Utility Room it is 25 litres/min. So a substantial difference with the kitchen hot from the new monobloc being especially poor.

We have gravity hot water. The head is at least 5.0m. The new monobloc taps are rated at 0.3bar, 3 metres. The tails to both monoblocks appear to be 10mm at final entry. Both Rooms have 15mm service valves before tap-tails.

So the company Manager is busy asking the Blanco manufacturer for ideas. However I can't help thinking the issue must lie with the installation since the 15mm drops from both Utility Room and Kitchen are off the same supply pipes.

Sorry for the length of post, just know like having all the info.

Views please

 

[snowhead]

The tap may be rated at 0.3bar but that just means at that pressure it will work.
The greater the available pressure the greater the flow will be.
The pipework may have a small influence on the flow rate butbasically the tap is not suitable of you want a high flow rate.
Any taps that use 8 or 10mm flexi or solid connections are going to have a low flow rate on a tank feed.
It needs to be 15mm and the tap spout needs to be equally sized.

Are the service valves full bore?

 

[Mdljk]

The tap may be rated at 0.3bar but that just means at that pressure it will work.
The greater the available pressure the greater the flow will be.
The pipework may have a small influence on the flow rate butbasically the tap is not suitable of you want a high flow rate.
Any taps that use 8 or 10mm flexi or solid connections are going to have a low flow rate on a tank feed.
It needs to be 15mm and the tap spout needs to be equally sized.

 

[Mdljk]

Thanks Snowhead

Aren’t nearly all kitchen taps on 8mm or 10mm tails these ‘combi-boiler’ days? I’ll look online for 15mm-tail monoblocks - or am I only going to get this with non- monobloc. I wonder if you can get 0.1 bar kitchen monoblocs. Will research and see.

Finally, would you consider 4.5 litres/minute acceptable for hot water flow rate at a kitchen sink or is the 9.5 flow rate of my Utility room (also monobloc) more thr norm? Is 4.5 litres/minute (see first video) acceptable or should I be asking the One-stop-shop kitchen company to source an alternative tap?

Any advice gratefully received.

 

[snowhead]

4.5 is fairly low.

My own kitchen mono tap is 5.5l/m with a tap rated 0.2bar and with 6mtrs head tank fed and I thought mine was slow when I picked and fitted it but wanted the style so tollerate it.
To get 5.5l/m I had to take the diffuser out the end of the spout.
It's got a full bore iso valve on it and is 15mm from near the cylinder upstairs.

In my bathroom upstairs with a conventional 1/2" basin tap it's around the same flow rate but with 3mtrs less head, on a hand basin it's not so noticeable.

Yes most taps are designed for the Continent which are mainly mains fed.
There are a few older U.K tap styles around, but not many.
1/4 turn is also part of the restriction.
The monobloc I had originally had 10mm tails, but a large free flowing spout

 

[Mdljk]

4.5 is fairly low.

My own kitchen mono tap is 5.5l/m with a tap rated 0.2bar and with 6mtrs head tank fed and I thought mine was slow when I picked and fitted it but wanted the style so tollerate it.
To get 5.5l/m I had to take the diffuser out the end of the spout.
It's got a full bore iso valve on it and is 15mm from near the cylinder upstairs.

In my bathroom upstairs with a conventional 1/2" basin tap it's around the same flow rate but with 3mtrs less head, on a hand basin it's not so noticeable.

Yes most taps are designed for the Continent which are mainly mains fed.
There are a few older U.K tap styles around, but not many.

Hi Snowhead

6.0 m that’s quite a height! But thanks, it helps to demonstrate my problem. Mine install is like yours 15mm from near cylinder. My basin taps upstairs have a poor flow rate but the previous kitchen taps and the current Utility Room taps (further along the overhead feed) were/are fine. I can only assume that 0.3 bar min rating is too much of a challenge for my 4.4 m head. Guess I’ll need to try 0.2 bar taps as 0.1 bar taps don’t seem to come in monobloc (which is telling!)

Thanks

 

[IND_Nick]

Just a quick one, have you check the filter/aerator at the end of the spout isn't blocked. I've been to a few that have solder/woodchippings etc in and reduced the flow substantially. It should unscrew by hand.
If not obviously reasons above, but worth a check.

 

[exedon2]

Maybe consider boosting the hot water for the whole house? Done properly the results transform poor flow rates.

 

[Mdljk]

4.5 is fairly low.

My own kitchen mono tap is 5.5l/m with a tap rated 0.2bar and with 6mtrs head tank fed and I thought mine was slow when I picked and fitted it but wanted the style so tollerate it.
To get 5.5l/m I had to take the diffuser out the end of the spout.
It's got a full bore iso valve on it and is 15mm from near the cylinder upstairs.

In my bathroom upstairs with a conventional 1/2" basin tap it's around the same flow rate but with 3mtrs less head, on a hand basin it's not so noticeable.

Yes most taps are designed for the Continent which are mainly mains fed.
There are a few older U.K tap styles around, but not many.

Hi Snowhead

6.0 m that’s quite a height! But thanks, it helps to demonstrate my problem. Mine install is like yours 15mm from near cylinder. My basin taps upstairs a …have a poor flow rate but the previous kitchen taps and the current Utility Room taps (further along the overhead feed) were/are fine. I can only assume that 0.3 bar min rating is too much of a challenge for my 4.4 m head. Guess I’ll need to try 0.2 bar taps as 0.1 bar taps don’t seem to come in monobloc (which is telling!)

Thanks

Maybe consider boosting the hot water for the whole house? Done properly the results transform poor flow

Just a quick one, have you check the filter/aerator at the end of the spout isn't blocked. I've been to a few that have solder/woodchippings etc in and reduced the flow substantially. It should unscrew by hand.
If not obviously reasons above, but worth a check.

IND_Nick and exedon2, I shall look into those two suggestions.