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]

Hey

Well seeming the materials to do that will cost more than £2-300 I don't think you've got any chance there.

Can you see the size of the pipe incoming to the combination valve? (The one next to the white vessel which is brass colour). With all the insulation it's difficult to see pipe sizes.

But first off, it doesn't appear they've done balanced cold supplies. Which won't help.

I’ll have a look again or ask the plumber when i can.

How can you tell it’s not balanced on the cold supplies?

 

[Gasmk1]

becasue he would have taken the balanced cold feeds fron then combination valve the rear tapping

 

[kash]

Bit of an update as I've properly used both showers today simultaniously for the 1st time since the new set up was installed.

-Main shower on with nothing else on - was ok.
-2nd shower went on - pressure dropped a little as expectd- but still just about ok but little weak
-Toilet flushed and tap opened - water stopped flowing in both showers. mrs was NOT HAPPY as she was taking a shower haha.

I cant deal with that.

Spoken to the plumber in regards to a solution.
Appears that an accumulator, whilst ideal, wont work as the size of tank needed just wont be fit sensibily or logistically.

The suggestion is to re-install a pair water storage tanks back into the level 2 loft, and if i understand correctly will work in the following way:

-Both showers will be fed via the twin shower pump from cold tank level 2 and hot unvented cylinder on level 1.
-incoming mains supply will top up the cold tanks on level 2 as they empty
-hot water will be pumped from hot unvented cylinder for everywhere else using a 2nd sinlge pump that we used before (I think this is what he said but i might be wrong about that.)

How does this solution sound? He said this will effectly work as its a breaker tank. Just need to work out costs. I know it will be a bit but I dont really have a choice.

A little dissapointed tbh as I kind of wish I had just stuck with the original set up which did what it needed to do and fairly well. All the research I did and people I spoke to though suggested that the new unvented system was the way forwards..... cant help but feel like it was money wasted at the moment.

I aslo asked what the flow rate was and it was circa 13-15L per minute at the mains

 

[ShaunCorbs]

What’s your mains pressure ?

nothing open ?

one tap open ?

 

[SJB060685]

Before I comment further can a pump be used for hot water outlets on an unvented cylinder @ShaunCorbs?

 

[Gasmk1]

this seems to point to your cold water main not being adequate

 

[EvilDrPorkChop]

What your plumber is suggesting is incorrect. You can't pump out of an unvented cylinder, you cannot also pump the cold from the tank and then have the hot supplied from the unvented.

He clearly doesn't know what he's doing, you need to get someone else in who can advise you much better.

As @ShaunCorbs says when need to know you incoming pressures, which you've been asked for a few times yet haven't provided them. You need to know these before you make any decision on what route to take.

 

[kash]

What’s your mains pressure ?

nothing open ?

one tap open ?

I cant remeber if i'm honest and I don't have a guage. However, as i've mentioned before, pressure at the taps is perfectrly fine at the moment, when the showers are not on.
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What your plumber is suggesting is incorrect. You can't pump out of an unvented cylinder, you cannot also pump the cold from the tank and then have the hot supplied from the unvented.

He clearly doesn't know what he's doing, you need to get someone else in who can advise you much better.

As @ShaunCorbs says when need to know you incoming pressures, which you've been asked for a few times yet haven't provided them. You need to know these before you make any decision on what route to take.

I will try to get these readings.

As for what he's suggesting, i've only wrote what I think he think he said - i could be wrong.

 

[Gasmk1]

pressure at the taps being fine doesnt mean you are getting the right flow to cope with 2 showers and all other serices toilets and basins

 

[SJB060685]

This is what I was going to say Pork Chop. Plumbing is not my thing but I always believed no pumps on unvented and certainly not mains hot hot and boosted cold, how would they be balanced? If at all. As we all said the incoming mains pressure and flow rates is the first thing you check before considering mains hot water.

 

[ShaunCorbs]

Before I comment further can a pump be used for hot water outlets on an unvented cylinder @ShaunCorbs?

not for the outlet but you can pump the supply to it eg break tank and pump if pressure is an issue

but it sounds like flow is the problem but until we get some figures we can’t say

 

[kash]

What your plumber is suggesting is incorrect. You can't pump out of an unvented cylinder, you cannot also pump the cold from the tank and then have the hot supplied from the unvented.

He clearly doesn't know what he's doing, you need to get someone else in who can advise you much better.

As @ShaunCorbs says when need to know you incoming pressures, which you've been asked for a few times yet haven't provided them. You need to know these before you make any decision on what route to take.

He told me it was measured at 1.6bar before he started the work. Not sure what it is now - need to re-measure when he is next here.

 

[SJB060685]

1.6 bar is not good for unvented. As I said above, around that pressure you need a breaker tank and pumped mains with accumulator.

 

[ShaunCorbs]

Ok when he’s here next week get him to fill this out

Pressure static (no outlets open eg just the pressure gauge open) is _______ bar
Pressure dynamic (one additional outlet open) is ______ bar
Flow static (one outlet open) is ______ Lpm
Dynamic (two outlets open) is ______ Lpm

 

[kash]

1.6 bar is not good for unvented. As I said above, around that pressure you need a breaker tank and pumped mains with accumulator.

So his suggestion of 'making up' a breakter tank in loft level 2 is not an unsensible one?

In his defence he has not confirmed if this is what he is going to do but said he will look into it more for me and come up with the best solution based upon the space that I have.
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Ok when he’s here next week get him to fill this out

Pressure static (no outlets open eg just the pressure gauge open)
Pressure dynamic (one additional outlet open)
Flow static (one outlet open)
Dynamic (two outlets open)

Sure - will do.

 

[SJB060685]

A breaker tank is installed on incoming mains to propert, it is pumped thereafter either buy a pump or negative head pump to an accumulator. Both breaker tank and accumulator need to be sized correctly and installed correctly. It's called a breaker tank to isolate house water from mains, preventing any back flow into street mains which could cause problems and harm others. What hes suggesting in the loft could be called a breaker tank but not in this sense. Google boosted mains and look up the above. 1.6 bar is nothing and like Shaun says you need to know static and dynamic pressure and flow. Your incoming mains may not be suited to your requirements and should of been considered when designing the system. Remember a larger incoming pipe will give greater flow rates.

 

[Scott_D]

What size and material is your incoming water main?

 

[kash]

A breaker tank is installed on incoming mains to propert, it is pumped thereafter either buy a pump or negative head pump to an accumulator. Both breaker tank and accumulator need to be sized correctly and installed correctly. It's called a breaker tank to isolate house water from mains, preventing any back flow into street mains which could cause problems and harm others. What hes suggesting in the loft could be called a breaker tank but not in this sense. Google boosted mains and look up the above. 1.6 bar is nothing and like Shaun says you need to know static and dynamic pressure and flow. Your incoming mains may not be suited to your requirements and should of been considered when designing the system. Remember a larger incoming pipe will give greater flow rates.

The I've read the manual and it says "Water supply An adequate and reliable mains water supply is essential to ensure Albion Ultrasteel, Ultrasteel Plus and Aerocyl cylinders deliver the quality and reliable performance you’d expect. We recommend a minimum supply pressure of 1.5 bar, with a flow rate of 25 litres/min. "

I defo don't have a flow rate of 25L per minute.

Just waiting to my guy to come back to me and will hopefully be able to get the readings requested.

Also, just for my understanding. Would we need a break tank AND accumulator, or one or the other?
I think he was saying that we would potentially install the tank on level 2 and pump this TO the unvented cylinder.

 

[SJB060685]

As I said plumbing is not my thing, my knowledge lies elsewhere in the industry. My understanding is you would use either an accumulator or a breaker tank, pump set and accumulator. The break tank is usually installed on the inlet to the property, away from areas of quiet interest due to pump noise and pumped thereafter to the dwelling outlets. You are sizing for both hot and cold pipework distribution, so the breaker tank will need to be sized correctly. This also provides a short fall should your incoming mains be subject to problems ie, work being done in the street. If pressure is ok (in your case borderline) then you could get away with just a suitably sized accumulator. With the pump set you are solely relying on it to provide the pressure and flow to the property, with the accumulator making use of the energy provided.
As I and others have said above, your incoming supply should have been the first thing to check when considering this type of system, quite often and what seems to be your case is the incoming mains to house will not be sufficient and upgrading is necessary, the bigger the supply line the better, pressure will be whatever it is by the provider but your flow rates will be much greater .

 

[kash]

As I said plumbing is not my thing, my knowledge lies elsewhere in the industry. My understanding is you would use either an accumulator or a breaker tank, pump set and accumulator. The break tank is usually installed on the inlet to the property, away from areas of quiet interest due to pump noise and pumped thereafter to the dwelling outlets. You are sizing for both hot and cold pipework distribution, so the breaker tank will need to be sized correctly. This also provides a short fall should your incoming mains be subject to problems ie, work being done in the street. If pressure is ok (in your case borderline) then you could get away with just a suitably sized accumulator. With the pump set you are solely relying on it to provide the pressure and flow to the property, with the accumulator making use of the energy provided.
As I and others have said above, your incoming supply should have been the first thing to check when considering this type of system, quite often and what seems to be your case is the incoming mains to house will not be sufficient and upgrading is necessary, the bigger the supply line the better, pressure will be whatever it is by the provider but your flow rates will be much greater .

I really appreciate all the advice you and eveyone else has given to do date. I'm no expert hence the reason I come on such forums. I like to try and understand as much as I can from non bias sources and not just rely on what 1 tradesman tells me.

In this instance, its obviously too late to go back - obviously these things should have been checked first. Whilst he did show me the flow rate and pressure, i never noted it down and I was told it was decent. However, looking at the manaul now I can see for myself that it probably isn't sufficient for the setup I now have; thus said, now need to find the best solution.

I feel like it's going to be a case of installing these tanks in the loft at the moment. Just hope it's not going to cost an arm and a leg to restore a decent shower and simultanious output in the house.

 

[SJB060685]

You did the right thing coming on this site, there is literally decades of experience between the users. Unfortunately like you said you're past the point of no return. Unfortunately again you have a couple choices, either pay lots more to upgrade incoming mains, add booster pumps, breaker tank and accumulator etc or pay to have an open vented system re installed with same layout as before to achieve the shower you desire, either way is likely to cost a fair amount. Unvented HW supply is a God send but as you've learnt the hard way it needs to be done properly and it appears your installer might not be as well informed as he suggests

 

[kash]

So this what he sent me in terms of the solution, based upon the space I have available (other than ripping out the new unvented tank)

I’ll ask him to take the pressure and flow readings before though.
..........
Installation of 3 x 25gallon tank in small loft to include supply of materials and tanks.

The tanks will be mains supplied and will give cold supply to the new unvented hot water cylinder.

These tanks will also supply cold feed to shower in ensuite and shower in main bathroom (which will be pumped by double pump allready on site, installed in small loft).

hot water will be pumped everywhere in the house by the other single pump installed in big loft (both pumps already on site and available from previous set up)

£730
......

 

[ShaunCorbs]

them pumps arnt suitable for boosting a whole house / what hes intending them for

 

[SJB060685]

Correct me if I'm wrong but is he suggesting piping the cold feed to unvented cylinder from these proposed new storage tanks in the loft?

 

[kash]

Correct me if I'm wrong but is he suggesting piping the cold feed to unvented cylinder from these proposed new storage tanks in the loft?

Yes i believe so....?