New quooker reducing the flow of the hot water

ThisIsWeird

silvercar said:

I’m not explaining it well. All the water comes out of the quooker tap - through this one tap, the cold is mains fed and powerful, the boiling is reasonably powerful, it’s just the hot that comes from the tank that is weak. 

As for the other taps around the house, they are all ok. So the only one that has an issue is the hot water that is coming through the quooker tap, but is delivered from the HWT. So any question of fitting a pump would be to benefit this one tap, as the others don’t need it. 

(It would also bring questions of where to position it, there is no room and no plug point in the cupboard housing the tank. But that is secondary).

I just wanted some reassurance that the plumber is correct in explaining away the low pressure and there isn’t something else that the plumber has glossed over.

You are explaining it fine - perhaps we're not explaining the explanation properly!

Your Quooker tap is almost certainly designed for 'high pressure' systems, which means either combi boilers, or unvented (mains pressure) hot water tanks. If you had one of these two types of system (which you don't), you'd find that the cold, the hot, and the Quook flow from your spout would be pretty much identical (actually, the Quook would always be less, as the machine needs to heat the water instantly first). But, the H and C would flow the same on 'mains' systems.

High pressure taps like this have small internal bores in them, and are not suitable for low pressure systems like yours. Yours is not only 'low pressure', but is a low-pressure low pressure system, as you've pointed out that your utility room's hot flow - whilst 'ok' - isn't amazing either. So, if you fitted a 'high pressure' tap to your ute, Quook type or no, then your ute's hot flow would be as pitiful as your kitchen's is now.

Your solutions are either to revert to low-pressure taps for your kitchen, and fit a separate Quook for just the 'instant hot' - which you've said, understandably, is a no-no - or to boost your domestic hot supply a wee bitty.

I hate pumped systems. Every one I've had experience of - and that's just two at most - have been thrummy and gushy. Too powerful. You turn on a tap slowly and nothing happens - just a trickle. You ease it open a touch more and THRUMMMMM. And GUSSSHHHH. Hate them.

The Grundfos, tho', is essentially the same device as their famous CH circulating pump, except with a fitted flow switch to make it 'auto'. Their circ pumps are near silent in use, so I expect these to be similar - and that's what my bro reported. But the best thing is, they are not stupidly powerful, they are just 'normal'. They only add around a half-to-threequarters bar to the pressure, which will be transformative ('cos a low pressure supply will be usually around 0.1 to 0.2 bar), but not 'stupid'. Most domestic booster pumps are 2 bar and stuff like that. Really gushy and firey and annoying.  

First, I'd ask Quooker themselves whether (a) this specific tap is ok on low-pressure systems (and mention it's a weak-low...), and (b) whether they make low pressure alternative for the hot domestic side of the tap. I suspect they don't. If they do, then collar your plumber and insist they swap it (if they supplied it...)

Then, armed with the alternatives - none - buy that near-new Grundfos for £100, or a new one for £200+, and install it near your hot cylinder where it'll be out of the way. There almost certainly will be room, and if you have an immersion heater, you'll have power. Make sure the plumber follows the instructions on the pump positioning - in essence, I think it's that it must pump upwards.

Then come back on here and give me a giant cyber kiss. 'Cos every hot tap in your house will be singing.

silvercar

ThisIsWeird said:

silvercar said:

I’m not explaining it well. All the water comes out of the quooker tap - through this one tap, the cold is mains fed and powerful, the boiling is reasonably powerful, it’s just the hot that comes from the tank that is weak. 

As for the other taps around the house, they are all ok. So the only one that has an issue is the hot water that is coming through the quooker tap, but is delivered from the HWT. So any question of fitting a pump would be to benefit this one tap, as the others don’t need it. 

(It would also bring questions of where to position it, there is no room and no plug point in the cupboard housing the tank. But that is secondary).

I just wanted some reassurance that the plumber is correct in explaining away the low pressure and there isn’t something else that the plumber has glossed over.

You are explaining it fine - perhaps we're not explaining the explanation properly!

Your Quooker tap is almost certainly designed for 'high pressure' systems, which means either combi boilers, or unvented (mains pressure) hot water tanks. If you had one of these two types of system, you'd find that the cold, the hot, and the Quook flows from your spout would be pretty much identical (actually, the Quook would always be less, as the machine needs to heat the water instantly).

High pressure taps like this have small internal bores in them, and are not suitable for low pressure systems like yours. Yours is not only 'low pressure', but is a low-pressure low pressure system, as you've pointed out that your utility room's hot flow - whilst 'ok' - isn't amazing either. So, if you fitted a 'high pressure' tap to your ute, Quook type or no, then your ute's hot flow would be as pitiful as your kitchen's is now.

Your solutions are either to revert to low-pressure taps for your kitchen, and fit a separate Quook for just the 'instant hot' - which you've said, understandably, is a no-no - or to boost your domestic hot supply a wee bitty.

I hate pumped systems. Every one I've had experience of - and that's just two at most - have been thrummy and gushy. Too powerful. You turn on a tap slowly and nothing happens - just a trickle. You ease it open a touch more and THRUMMMMM. And GUSSSHHHH. Hate them.

The Grundfos, tho', is essentially the same device as their famous CH circulating pump, except with a fitted flow switch to make it 'auto'. Their circ pumps are near silent in use, so I expect these to be similar - and that's what my bro reported. But the best thing is, they are not stupidly powerful, they are just 'normal'. They only add around a half-to-threequarters bar to the pressure, which will be transformative ('cos a low pressure supply will be usually around 0.1 to 0.2 bar), but not 'stupid'. Most domestic booster pumps are 2 bar and stuff like that. Really gushy and firey and annoying.  

First, I'd ask Quooker themselves whether (a) this specific tap is ok on low-pressure systems (and mention it's a weak-low...), and (b) whether they make low pressure alternative for the hot domestic side of the tap. I suspect they don't. If they do, then collar your plumber and insist they swap it (if they supplied it...)

Then, armed with the alternatives - none - buy that near-new Grundfos for £100, or a new one for £200+, and install it near your hot cylinder where it'll be out of the way. There almost certainly will be room, and if you have an immersion heater, you'll have power. Make sure the plumber follows the instructions on the pump positioning - in essence, I think it's that it must pump upwards.

Then come back on here and give me a giant cyber kiss. 'Cos every hot tap in your house will be singing.

Thank you, I was beginning to feel very inadequate.

The only Quooker brand that would cope, is what they call the ‘combi’, this is cold water feed only as the Quooker supplies the boiling and the hot water, dispensing with the need for the HWT to be involved. Not supplied by the plumber, plumber sourced by the builder, so I suspect I’m stuck on that one. Kitchen designer gave me the name of a white goods supplier, who produced a list that I signed off on that just had Quooker listed, so I’m probably on my own on that one. The combi costs a few hundred pound more, so roughly the same as a pump. 

Will see how I get on. Im over budget already. I’m slightly nervous of adding a pump to the existing systems, parts of it are very old and things have really played up since we have had the building works done. 

ThisIsWeird

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!

silvercar

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!

Thanks, I’ve certainly learned a lot!

It plugs in with a standard 3 pin plug. Quooker quotes running costs at 3p per day. (To be honest, I would never have spent this money on a boiling tap if it wasn’t for the fact that we are re-doing the kitchen and was told that it’s a necessity for the kitchen we are having. Same as the all singing and dancing built in microwave that also warms plates, grills and oven heats, rather than my trusty £100 stand alone microwave from Argos!)

The old kitchen tap had mains cold water and hot water from the tank that was “adequate”. I would say that the utility room sink now has hot water that is nearly adequate (and given it’s a utility room, that’s good enough). It’s just this kitchen tap that is slightly less than adequate. But I may learn to live with it, it was just puzzling. The plumber is contracted by the builder, my impression of him is that he is good but takes the easy route, so I wanted to check that what he had done was correct and the lower flow is because of the way the Quooker connects rather than anything else.

PS the CWT is in the loft, the HWT is downstairs. Though the main bathroom has hot water from this tank and the pressure is OK, so maybe the pipes go upstairs then down again.

grumbler

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 costs 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.

ThisIsWeird

silvercar said:

Thanks, I’ve certainly learned a lot!

It plugs in with a standard 3 pin plug. Quooker quotes running costs at 3p per day. (To be honest, I would never have spent this money on a boiling tap if it wasn’t for the fact that we are re-doing the kitchen and was told that it’s a necessity for the kitchen we are having. Same as the all singing and dancing built in microwave that also warms plates, grills and oven heats, rather than my trusty £100 stand alone microwave from Argos!)

The old kitchen tap had mains cold water and hot water from the tank that was “adequate”. I would say that the utility room sink now has hot water that is nearly adequate (and given it’s a utility room, that’s good enough). It’s just this kitchen tap that is slightly less than adequate. But I may learn to live with it, it was just puzzling. The plumber is contracted by the builder, my impression of him is that he is good but takes the easy route, so I wanted to check that what he had done was correct and the lower flow is because of the way the Quooker connects rather than anything else.

PS the CWT is in the loft, the HWT is downstairs. Though the main bathroom has hot water from this tank and the pressure is OK, so maybe the pipes go upstairs then down again.

Where is your kitchen in relation to the hot tank?

ThisIsWeird

https://www.quooker.co.uk/installation-criteria

"The minimum hot and cold water pressure required is 2 bar. COMBI tanks (I think they mean their 'combi' model tap) only require a cold water supply"*

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

That would suggest that the Quook model you have (ie, that also has a conventional hot supply) can only be used with combi boilers, unvented hot cylinders (ie mains pressure) and pump-boosted supplies.

(Even the Grundfos I mentioned would in theory not be good enough... But I bet it would :-) )

So, the installing plumber almost certainly made an error installing that Quook on your system, and him now blaming your system ain't good enough.

So, I think you'd be within your rights to insist the plumber, or whoever made the judgement, takes some responsibility.

Silvercar, can you describe what the hot flow is like? Any chance of a photo? How does it compare with the Quooker's instant-hot flow?

*I see that Grumb actually said this in the second post on this thread! I missed that!

grumbler

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.

ThisIsWeird

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 :-)

silvercar

The hot water tank is say a metre off the ground, the other side of the kitchen. The cold water tank is in the loft. The bathroom (upstairs) has reasonable hot water flow. The kitchen (downstairs) has poor hot water flow. The utility room (downstairs) has nearly OK hot water flow. The boiler is in the kitchen, the mains cold water comes into the kitchen. There must be some up and over arrangement taking water pipes from the boiler to the hot water tank, I'm guessing at kitchen ceiling level. whether the hot water from the tank goes upstairs and then back down to the kitchen or just to kitchen ceiling level and then back down I don't know. The rate in the bathroom is ok, so something is coping with the hot water tank being at a lower level than the bath!

Flow rates

hot water from tank via quooker tap - 2.5 litres/minute

cold (mains water) through quooker tap - 6 litres/ minute

utility room hot water from tank 2.75 litres/ minute

bathroom sink hot water from tank 4.4 litres/ minute