New quooker reducing the flow of the hot water

silvercar

grumbler said:

silvercar said:

ThisIsWeird said:

Dinnae feel inadequate, as this is not layperson stuff. And you are much more informed now.
The Quook 'combi' sounds like, perhaps, a more powerful tap, so it can heat at a fast enough rate to be able to dispense with a separate hot supply to the tap? That sounds like an 'option' for some installs, say for new plumbing where only a single cold mains needs be laid. But, even if a good solution, it's super-crazy money.
Does your current Quooker require a separate electrical power supply, or does it just 'plug in'? 

Anyway, I think we know what the 'issue' is, and that's a weak gravity supply. There are many such gravity systems which are perfectly ok, and can work with 'high pressure' taps, but these will tend to have their CWS located high up in the loft, with well-designed pipe runs. So whilst the hot flow from a kitchen tap would not be as good as the mains cold side, it would still be 'fine'. 
It sounds, from what you say, that your hot supply is just about 'adequate' in any event, so adding a 'mains' tap to that was always going to nobble it.
There are other possibilities, tho' - we can't rule out that your plumber didn't install narrow-bore isolating valves to your new Quooker, and that certainly wouldn't help. Ie, the restriction could be before the tap. And, even possible, the valve might not be fully open. Unlikely, but not impossible.
I'd urge you to contact Quooker. Tell them you have 'gravity vented' hot water, and the flow from the old hot tap was 'fine', but no more than that (describe it as accurately as you can). Then ask if your new tap is suitable.
If it isn't, ask for solutions. 
They should know everything about their taps!

It plugs in with a standard 3 pin plug. Quooker quotes running costs at 3p per day.

Reportedly, boiling a cup of water cost more than 1p. So with 3p you are limited by 3 cups. And this is if the running water is heated, i.e. it's not stored pre-heated in some small tank. And if it's running water, with a 3-pin plug (3kW) I expect the flow to be really small. Electric showers are about 3 times more powerful and heat water to just 40C, not to 100C.

I git it wrong. The standby consumption costs 3p/ day. 

silvercar

ThisIsWeird said:

grumbler said:

ThisIsWeird said:

Your hot water will be at around 0.2bar, a tenth of the min.

Why 0.2? have I missed anything?

For a two storey house with a tank in the loft it's about 0.5 - not that it makes a big difference in this case.

No, not missed anything.

That's very much a ballpark figure, and once pipe runs and all sorts are taken into account, the actual arrival pressure from most domestic gravity systems will be in the 0.2bar ballpark. Says Google, and she's never wrong.

Also, I suspect - but don't know - that Silvercar's setup has the hot tank on the ground floor, but their kitchen on the 1st - I did ask for clarification on this.

In any event, it's the wrong tap for their system.

If the hot is being delivered in a reasonable trickle, then I am personally confident that the Grundfos will make it perfectly acceptable. But that has to be SC's call.

Their alternative solutions are potentially costly and disruptive, and to live with it simply insane.

I know what I would do. I'd buy that £100 jobbie, trial it, and if it didn't work I'd remove it and sell it on. My only concern about the Grundfos is whether there's enough existing flow to trigger the pump into operation.

Looking at the Quooker site, there's seemingly a surveying process that should be carried out - are the pressures 2+bar, is there a power supply within 500mm, that sort of thing. So I suspect Silver's situation - who is 'responsible' - may come down to who made the decision to go ahead and install this unsuitable tap, and on what basis.

If SC was led to understand things would be fine, and they clearly aren't - and won't be without change - then the faulty party may be obliged to come up with the solution. That would appear to be:

1) A conventional mixer tap that will cope with the low pressure, and a separate mini-Quooker alongside.

2) Replace the existing Quooker with their 'combi' version, which only requires a cold supply.

3) Boost the existing hot supply.

Oh, or

4) throw away the Quooker :-)

Kitchen designer just said you'll want a quooker, white good company supplied a quooker. Builder contracts people to fit it. Plumber arrives with a list of tasks to do, one of which is install quooker. Which he does. He then warns and demonstrates the low flow, says it could be fixed with a pump and let him know if I want a quote for that. So plumber will say, he did what he was tasked to do. 

ThisIsWeird

silvercar said:

ThisIsWeird said:

grumbler said:

ThisIsWeird said:

Your hot water will be at around 0.2bar, a tenth of the min.

Why 0.2? have I missed anything?

For a two storey house with a tank in the loft it's about 0.5 - not that it makes a big difference in this case.

No, not missed anything.

That's very much a ballpark figure, and once pipe runs and all sorts are taken into account, the actual arrival pressure from most domestic gravity systems will be in the 0.2bar ballpark. Says Google, and she's never wrong.

Also, I suspect - but don't know - that Silvercar's setup has the hot tank on the ground floor, but their kitchen on the 1st - I did ask for clarification on this.

In any event, it's the wrong tap for their system.

If the hot is being delivered in a reasonable trickle, then I am personally confident that the Grundfos will make it perfectly acceptable. But that has to be SC's call.

Their alternative solutions are potentially costly and disruptive, and to live with it simply insane.

I know what I would do. I'd buy that £100 jobbie, trial it, and if it didn't work I'd remove it and sell it on. My only concern about the Grundfos is whether there's enough existing flow to trigger the pump into operation.

Looking at the Quooker site, there's seemingly a surveying process that should be carried out - are the pressures 2+bar, is there a power supply within 500mm, that sort of thing. So I suspect Silver's situation - who is 'responsible' - may come down to who made the decision to go ahead and install this unsuitable tap, and on what basis.

If SC was led to understand things would be fine, and they clearly aren't - and won't be without change - then the faulty party may be obliged to come up with the solution. That would appear to be:

1) A conventional mixer tap that will cope with the low pressure, and a separate mini-Quooker alongside.

2) Replace the existing Quooker with their 'combi' version, which only requires a cold supply.

3) Boost the existing hot supply.

Oh, or

4) throw away the Quooker :-)

Kitchen designer just said you'll want a quooker, white good company supplied a quooker. Builder contracts people to fit it. Plumber arrives with a list of tasks to do, one of which is install quooker. Which he does. He then warns and demonstrates the low flow, says it could be fixed with a pump and let him know if I want a quote for that. So plumber will say, he did what he was tasked to do. 

I fear they'll all say, "I only suggested..."!
But I'd have thought the plumber should know. But perhaps not - he might not be familiar with Q's.
And, a 'combi' Q could have been ok. Hey-ho.
I'm surprised at how poor your utility room is. It's seemingly only fractionally better than the kitchen tap? And yet presumably has a 'normal' tap on it?

The location of the boiler is immaterial - all it does is heat the hot cylinder, and not affect its pressure.
The position of the hot cylinder is also largely meaningless. 
What's important is the 'head', and that's how much higher the CWS (which is the driving force) is about the outlet. So, all other things being equal - pipe diameters, length, no of bends, etc - a tap on the first floor should be weaker than on the ground. So, yes, it looks like there's more at play, such as tortuous routes, and pipe diams.
Whether it's worth a plumber looking at your overall layout and seeing if there's a better route from your hot cylinder to your kitchen and ute taps, I don't know. Or if there is any other cause for the particularly poor flow on the ground floor, when it should actually be the best.
Really, your call on what to do. But I know what I would try.

silvercar

What's important is the 'head', and that's how much higher the CWS (which is the driving force) is about the outlet. So, all other things being equal - pipe diameters, length, no of bends, etc - a tap on the first floor should be weaker than on the ground. So, yes, it looks like there's more at play, such as tortuous routes, and pipe diams.

I'd guess there are 8 90 degree turns between the hot cylinder and the taps, whereas there may be only 4 to the bathroom. The single hot water pipe travels from the cylinder in the middle of the house making 7 turns on route before a T junction on the back wall. The T junction comes down from ceiling height to tap height where the T junction takes the hot water to both sinks.

silvercar

Plumber visited. 

Turns out the quooker and utility taps are both designed for high pressure systems, hence the pipes to them are narrow and therefore the flow lower than the other taps around the house which would have been designed for low pressure systems.

This explains why the other taps have better flow. There is a mini pump that is designed for one tap only that could be fitted for these taps that would improve things. He is going to get me a price.

ThisIsWeird

Sounds as tho' you are getting there.
Not an option to fit the correct taps, and then have a separate single Quook?

Where would this pump go, has he said? If it thrumms audibly, it could be very annoying.

silvercar

ThisIsWeird said:

Sounds as tho' you are getting there.
Not an option to fit the correct taps, and then have a separate single Quook?

Where would this pump go, has he said? If it thrumms audibly, it could be very annoying.

I don't really want another tap. If I did it would involve getting the kitchen worktop people back to make a hole in the quartz, so probably cost as much as having a pump. The pump would go under the sink and use the power supply already there (though would mean a double adaptor)
Possibly an option for the utility room.

ThisIsWeird

I hope it's a nice pump! 
Good luck. Please report back when it's done.