Not happy with with new unvented system, although it works fine. Shower pressure issue

[kash]

Old setup.
Vented system - indirect
x2 Cold water tank in the loft. x2 80L Hot water tanks, regular boiler and stuart turner 4bar twin shower pump for the master bedroom shower. Worked pretty good, although the tanks were manky and old. The shower though was epic and used to blast water out. The house was gutted for refurbishment so plumber advised to change the set up for a new unvented system, that would deliver mains water pressure throughout the house. which it does.

New set up
Kingspan 300L horizontal tank. No shower pump and just the regular boiler. It’s all installed correctly, signed off and actually works quite well. All the taps and showers get mains water pressure.

Problem
I got too used to the shower pump pressure. The showerhead we have is an XL rainwater shower head and used to love the water blasting out. Whilst the showers still ok, it's just ok and not amazing anymore. If the shower in the family bathroom is run, there's a slight drop in pressure which i was expecting, but this makes the shower experience even less enjoyable.

Is there a solution?
We can’t install the same shower pump on the mains as it would draw too much water from the rest of the house and stop the other taps working - and probably mess with neighbours too. Assume this would also stop things like toilets refilling and draw air once water supply is exhausted.

So my questions are..... What is the solution for me to have a dedicated water supply for the shower again, so that I can use the pump?
Can I install a smaller vented system in addition to the unvented system that I have? The plumbers going to have a think on the best way of achieving this and let me know a price, but thought I’d ask on here too.

I know it’s potentially an expensive addition... but it just depends on cost. The shower is absolutely ok as it is, but i know how good it was and just wanted to make it awesome again.

Are there any other solutions that can be used with the new unvented tank I have?

 

[kash]

Non of them are correct let’s see what he says

he's just come back to me suggesting that this set up will be the one he intends to use.

What yould your suggestion be if none of them are correct?
updated diagram below.

I have looked at the Grundfos Scala2 pump you sent the link to. If I do get this, would it go BEFORE the unvented cylinder and FROM the water talnk in the loft.

Shaun - any chance of a quick chat?
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Non of them are correct let’s see what he says

also need them figures ?

I'll get those figures thursday.

 

[ShaunCorbs]

You can’t pump from the outlet of the unvented cylinder (this would concern me he thinks he can do this) you sure he’s g3 registered?

would go water tanks
Pump
Cold supply to the Unvented cylinder
Cold Balanced supply to the bathrooms

 

[SJB060685]

You can’t pump from the outlet of the unvented cylinder (this would concern me he thinks he can do this) you sure he’s g3 registered?

would go water tanks
Pump
Cold supply to the Unvented cylinder
Cold Balanced supply to the bathrooms

I think his plumber is suggesting using the unvented cylinder as vented now Shaun!?

 

[kash]

You can’t pump from the outlet of the unvented cylinder (this would concern me he thinks he can do this) you sure he’s g3 registered?

would go water tanks
Pump
Cold supply to the Unvented cylinder
Cold Balanced supply to the bathrooms

Really appreciate the feedback and help - I don't want to waste any more money and time.

I'm going to show this thread to him later.

Someone actually came out to check his work and a NAPIT certificate was issued?

Is the now attached what your suggesting based upon your last comment (i ask as not sure what the 'balanced' cold bit refers to)

These are the tanks he is supplying: Polytank Cold Water Tank 25gallon (UK) 690 x 515 x 520mm - https://www.NoLinkingToThis/p/polytank-cold-water-tank-25gallon-uk-690-x-515-x-520mm/10500

The file can be edited from think link via draw.io if anyone wishes to edit?

Google Drive: Sign-in

 

[ShaunCorbs]

Will draw something up later

 

[kash]

Will draw something up later

Thank you. He's supposed to be coming to do the work thursday so trying to get the info I need before then to ensure we have the best set up/solution.

 

[ShaunCorbs]

like this would be the only way i would do it

need to know your supply so can work out if the tanks are enough eg 70l

 

[SJB060685]

So the pump would go on cold inlet to cylinder and pump through it to HW outlets Shaun?

 

[kash]

like this would be the only way i would do it

need to know your supply so can work out if the tanks are enough eg 70l

Thanks a million.

I think that all makes sense to me- apart from the unvented control block. What is that/how does it it work? Is this another unit device- rough cost?

And I see now shower pumps here- is there any way I could use this instead of the Grundfos pump as it’s at least another £400 ontop or the £700 he’s quoted me to do this week work- ontop of the £16-700 ive already paid.

Will show this to my guy and see what he thinks.

Can’t thank you enough for your input
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like this would be the only way i would do it

need to know your supply so can work out if the tanks are enough eg 70l

Also, my unvented tank is 300L So think the 3 25gallon tanks = 340ish L? Should be enough?

 

[ShaunCorbs]

So the pump would go on cold inlet to cylinder and pump through it to HW outlets Shaun?

yes and being fed via the tanks so its boosted upto what every you set the pumps at then reduced down at the control block
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Thanks a million.

I think that all makes sense to me- apart from the unvented control block. What is that/how does it it work? Is this another unit device- rough cost?

And I see now shower pumps here- is there any way I could use this instead of the Grundfos pump as it’s at least another £400 ontop or the £700 he’s quoted me to do this week work- ontop of the £16-700 ive already paid.

Will show this to my guy and see what he thinks.

Can’t thank you enough for your input
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Also, my unvented tank is 300L So think the 3 25gallon tanks = 340ish L? Should be enough?

sorry thought your tanks were in Litres 😀 should be enough but depends on your mains flow rate dynamic

also the control block he should know what this is and its already fitted

tbh you shouldnt have to pay anything as its his mistake not checking things first and good enough

 

[kash]

yes and being fed via the tanks so its boosted upto what every you set the pumps at then reduced down at the control block
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sorry thought your tanks were in Litres 😀 should be enough but depends on your mains flow rate dynamic

also the control block he should know what this is and its already fitted

tbh you shouldnt have to pay anything as its his mistake not checking things first and good enough

Whilst I agree with you, I don’t know of any trades person that I’ve come across yet that would swallow that much material and labour (relative to be size of the job). He’s already been paid for the job so I can’t even challenge him with payment. He did agree to charge me minimum labour for this change though. Getting someone new in would also cost me and then there’s finding someone willing enough with the knowledge.

If you’re able to clarify about the use of the shower pump I think this should be enough info to go back to him with? Hopefully I can use one of my existing pumps if I can.

Am I right in understanding that with the setup you’ve proposed, the pressure at the showers would now just be at whatever the output of the chosen pump is? I was very happy with the previous setup and the output at the showers which came straight from the pump (just wondered if I’d still need the shower pumps with your set up)

He’s now booked the job in for Monday as he he didn’t want to commit to 1 day on Thursday and I can’t do Friday or this weekend.
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I guess also what I'm trying to understand is, what is the difference between a shower pump and the pumps you've recommended.
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OK. So i've spoken with the plumber.

@ShaunCorbs he agrees that your set up whilst better and ideal, unfortunatly won't work in my situation, as apparenty it means more piping configuration changes and breaking a wall and some ceilings (as I have the 1st floor loft where there current cylinder is, and the 2nd floor loft where the water tanks would be). Now there is no way i'm going to start ripping things open and doing all of that, as he said he could do it, but the additional labour and hardware costs would be substantially more. And the house has just been finished and decorated. Again, i'm just taking his word on this.

He became slightly frustrated and said that he could easily walk away from the job, but he's confident that the pressure and flow rates were adequate at the mains before he took on the job and he will show me. He's said he's fairly certain that my water softer is responsible for much of the drop in flow/pressure too but we will test this next week. He said if the flow rate was more than 15L at the mains, then it's just a case of me not being happy as I was used to the previous shower pump set up.

I asked about pumping out of an unvented cylinder - he said that effectivly the new unvented cylinder would become vented so this wouldnt be a problem. So I dont think I have any choice but to go with his proposed solution.

On another note, if the tank is no longer 'unvented', would it still need the annual servicing? I've just signed up to an annal service plan with kingspan for the warranty purposes, so would this be a waste of money? They are supposed to be coming on friday to inspect in insulation. Do you think it's worth postponing this until AFTER he has done all the changes or just cancel it all together?

 

[John.g]

Is su1-revised his final proposal?, it may be just the way he has drawn it but its showing two (double) booster pumps in series to shower1 and shower2, is this correct?.

 

[EvilDrPorkChop]

Basically what he's proposing is incorrect and it would need to be done the way @ShaunCorbs is suggesting if you wanted to go down that route.

I can't believe your even proceeding with all of this before fully assessing the situation. You've not got any static/dynamic water pressure figures, pipe sizing from your water main to the cylinder combination valve or flow rates. It could be even something as simple as the filter on the shower or combination valve is blocked (Which has happened before) All these things are relatively simple to check.

In relation to Kingspan - they'll just invalidate your warranty once your plumber has had a butcher at what he's proposing! The cylinder won't become just a 'vented' cylinder because he's stuck a breaker tank on it.

 

[kash]

No, I 've just realised this is a mistake on my behlaf on the way i've drawn it. there are NOT two double pumps in series.

The revised final proposal that his is suggesting (with my error corrected) is now attached
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Basically what he's proposing is incorrect and it would need to be done the way @ShaunCorbs is suggesting if you wanted to go down that route.

I can't believe your even proceeding with all of this before fully assessing the situation. You've not got any static/dynamic water pressure figures, pipe sizing from your water main to the cylinder combination valve or flow rates. It could be even something as simple as the filter on the shower or combination valve is blocked (Which has happened before) All these things are relatively simple to check.

In relation to Kingspan - they'll just invalidate your warranty once your plumber has had a butcher at what he's proposing! The cylinder won't become just a 'vented' cylinder because he's stuck a breaker tank on it.

The filters have all been checked and they are clear. It's defo nothing being blocked.
I can measure flow rates but not the pressures and I dont have the tools or knowhow. I will ge these as soon as I can.

I'm going to let him digest this thread and proposal. I'm hoping there's a way we can make shauns proposal work somehow.
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OK UPDATE

We've come up with a way to actually put the x3 tanks that were going to go in the 2nd floor loft into the 1st floor loft. This means we can actually just put in 1 bigger tank as opposed to 3 smaller tanks.

This way we can actually do it properly and maintain the vented system.

He's going to re-spec up and provide me an updated quote later.
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SCALA2

SCALA2 is an integrated, self-priming, compact water booster pump. It is designed for perfect pressure inside the home. It’s quiet, easy to install, and maintains consistent pressure in all taps at all times.

uk.grundfos.com

ESYBOX MINI 3 | DAB Pumps

Esybox Mini 3 has a different appearance than any other booster set and is small and completely integrated. Once you install and use it, you realize that the real difference is in the comfort and performance. Esybox Mini 3 uses the most advanced DAB technologies to create constant pressure...

www.dabpumps.com

thats rated for constant use

Hi @ShaunCorbs - Are there any other recommendedations for a pump?

Based on what i'm seeing, we can use the shower pump right?
Are there differences with the booster pumps with a tank? Is the Grundfoss one you listed the same thing?

 

[ShaunCorbs]

Warning Long Long Post

Not for for purpose / design spec eg doesn’t meet minimum spec for unvented manufacturers instructions will list these / g3 also

Shower pumps aren’t rated for constant use you will see listed on them 5/25 or they will say 5 mins use 25 mins rest / cool down etc

As for pressure would be either control group spec eg 3.5 bar or what ever you set the pump at if lower

rated for constant use and suitable for the design spec

sorry don’t understand how it’s more as you still need to get the pipe work two and from the tanks etc

they should have about the same pipe work supply side eg from the tanks

also if your shower pump are positive pressure models and not universal/ negative I’m doubtful there will be enough head pressure to activate them

Bypass the softener and find out or measure the flow before but remember you will need a minimum of 25lpm for an unvented some manufacturers recommend no lower than 20lpm but I believe g3 regs are 25lpm and 3.5 bar

if there not well he’s not done his job hence the problems with not much flow when more than one outlet is used he should of warned you in the beginning you might need x to bring it up to your desired requirements

Yes everything that’s on the install now would get removed except the cylinder eg expansion vessels control group etc

No wouldn’t need inspections / servicing yearly but I wouldn’t count on warranty being valid either as your not using the cylinder as it’s designed for eg mains pressure

also just going back to the pump (shower) there’s no delicate shower pump feed on them so you could start running with dirty water eg air mixed

as for moving the tank to the same room as the cylinder this isn’t going to be good unless you have Universal/neg pumps as there isn’t enough head

you would need a min of 7-8m from the bottom of the tank to the pump for positive

 

[kash]

Warning Long Long Post

Not for for purpose / design spec eg doesn’t meet minimum spec for unvented manufacturers instructions will list these / g3 also

Shower pumps aren’t rated for constant use you will see listed on them 5/25 or they will say 5 mins use 25 mins rest / cool down etc

As for pressure would be either control group spec eg 3.5 bar or what ever you set the pump at if lower

rated for constant use and suitable for the design spec

sorry don’t understand how it’s more as you still need to get the pipe work two and from the tanks etc

they should have about the same pipe work supply side eg from the tanks

also if your shower pump are positive pressure models and not universal/ negative I’m doubtful there will be enough head pressure to activate them

Bypass the softener and find out or measure the flow before but remember you will need a minimum of 25lpm for an unvented some manufacturers recommend no lower than 20lpm but I believe g3 regs are 25lpm and 3.5 bar

if there not well he’s not done his job hence the problems with not much flow when more than one outlet is used he should of warned you in the beginning you might need x to bring it up to your desired requirements

Yes everything that’s on the install now would get removed except the cylinder eg expansion vessels control group etc

No wouldn’t need inspections / servicing yearly but I wouldn’t count on warranty being valid either as your not using the cylinder as it’s designed for eg mains pressure

also just going back to the pump (shower) there’s no delicate shower pump feed on them so you could start running with dirty water eg air mixed

as for moving the tank to the same room as the cylinder this isn’t going to be good unless you have Universal/neg pumps as there isn’t enough head

you would need a min of 7-8m from the bottom of the tank to the pump for positive

Once again, thank you for your response.

The good news is, that he has agreed Install as per your proposed solution.

I have ordered the Grundfos scala2 pump too. I hope it is a decent pump and have gone on your recommendation alone.

He isn’t going to charge me more than he has already quoted (£700), but I did have to buy the new pump myself at circa £400

As for the tanks, I think we are still proposing to put them in the same loft space if possible to make install easier. Will this still be an issue when using the Grundfos scale 2 pump? Or should I push for these to go into the 2nd floor loft?

When I get the measurements requested- I will call him out on this as I’m fairly certain it’s less than the requirements you stated. Obviously as a consumer, I wasn’t to know this. I just read that it was better all round but there wasn’t too much talk or the required required flows and pressures when doing high level research.

He told me the pressure and flow that I have would be ok for most people so I went with it. If I had known; we wouldn’t be in this position now: but lesson learned.

So all in all- it’s circa another £1100 to sort the problem, but the vented system will be maintained and used in its intended manner.

I’m hoping to recover a little cash by selling the existing pumps on eBay. Infact, the Stuart turner one which retails at £388 on plumbnation already has a bid for £75 - and it still has 2 years warranty left (if anyone’s interested, let me know)

 

[ShaunCorbs]

Good to hear

You can fit them to your spec aslong as the pump isn’t above the tanks

It will be listed in the manufacturers instructions if you have them for the unvented cylinder

as for pump at 3.5 bar your looking around 40lpm output from the pump

my set up will need all the unvented stuff to stay as I’m sure you already understand

let us know how you get on / anymore questions etc

 

[kash]

Good to hear

You can fit them to your spec aslong as the pump isn’t above the tanks

It will be listed in the manufacturers instructions if you have them for the unvented cylinder

as for pump at 3.5 bar your looking around 40lpm output from the pump

my set up will need all the unvented stuff to stay as I’m sure you already understand

let us know how you get on / anymore questions etc

Thanks.

No the pump will certainly not be above the tanks (although I’ve just seen the manual and it seems it has a well suction mode - not that it matters in this case). It will be on the same level or below the tanks. Those figures sound promising for the shower.

On a side note: I also just opened every cold tap in the house (not including any showers) and found that the tap outlet furtherst away wouldn’t even output any supply when all the others were open.

As I closed other outlets, supply gradually came back as expected. The main kitchen tap remained acceptable throughout, but it would as it’s is the 1st outlet in the chain.

The input from you and everyone else has been invaluable so far- and a reason why I love forums (that give sensible responses).

I will certain provide updates as and when. I just hope that it all goes to plan and should be a fairly simple install going forwards.

 

[gpbeck]

At the tap with no flow the pressure would be zero (or worse!) so I hope that is upstairs. If its 5 m above kitchen tap you can be sure the dynamic pressure is less than 0.5Bar at the kitchen tap.

What is the flow from kitchen tap only, with softener, and with softener bypassed? All you need is a bucket and a timer to measure this now and it is VITAL information. Maybe a new mains supply pipe wouldn't cost much more than your plans if you can dig a trench.

 

[kash]

Update

So he came and did the work. I asked him to take measurements and we saw the below. I didn't take all the ones requested as he wasnt intirely in mood to faf about, and not sure how much difference it would have made given that he was on site to do the job anyway.

Direct from mains
Flow rate: 24L per min
Pressure: 2.4 bar
Flow rate AFTER the water softner: 14L per min
Mains incoming pipe: 15mm > this extended into loft space then converted into 22mm into the unvented tank

So it seems that the water softner (water2buy W2B200) was responsbile for a lot of flow / pressure loss. After testing and discussing, it was case of either removing the water softner and wasting £350 + the labour i paid to fit and gain better flow; but still not the amazing shower pressure that I was used to, and still have potential issues when mutiple outlets open, or, go ahead and install the tank and pump anyway and elminate any issues pre-emptivley.

I opted for the later, as this way, i'd have a 300L store of softened hot AND cold water and wouldnt have to worry about loss of pressure with multiple outlets open. It was an expensive solution / addition, but I think i'm happy with it. I need to actually use everything properly in the real world, but from what I played with for about 5 minutes, It seemed like I had both showers pumped (awesome pressure), and every outlet open with decent flow (i'll confirm this again when I have more time to go around and open everything and flush all the toilets at once. Had I never had the water softener installed, i do question If I would have just settled with the output but.... it is what it is and its done now.

I notice that I hear the pump run for a minute or two each time the hot outlet was open (I think as it was refilling the hot unvented tank), but the pump is pretty quiet and it seems like a small price to pay for the solution. Obviously I expect the pump to run for longer when showering, but again, its pretty damn quiet so it's not so bad.

Here's a few pics of the install. He ran out of 15mm pipe lagging but i'm picking some up after work and i'll do this myself as its a 10 minute job. I've got Kingspan coming in to inspect the unvented tank install still on Friday to validate the warranty - so i'm hoping everything is ok and that the set up I now have is up to scratch.

1 thing he did moan about was that online or in the manual i think it said that it was a 3/4 inch fitting but it was actually a 1inch fitting (or the other way around - not sure) - so he had to make up an adaptor.

Thanks again @ShaunCorbs

I'll let you know how things go.

Happy to hear any comments, questions or feedback from what you can see in the pictures.
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At the tap with no flow the pressure would be zero (or worse!) so I hope that is upstairs. If its 5 m above kitchen tap you can be sure the dynamic pressure is less than 0.5Bar at the kitchen tap.

What is the flow from kitchen tap only, with softener, and with softener bypassed? All you need is a bucket and a timer to measure this now and it is VITAL information. Maybe a new mains supply pipe wouldn't cost much more than your plans if you can dig a trench.

Digging a trench wasnt an option unfortanatly.