Overcoming poor flow rate

[plumb_know]

Sorry for the essay

I hold BPEC unvented card, just seeking more experienced engineers advice

job Back ground:

customer bought house and inherited poor flow rate to (210litre) unvented megaflo in loft. Location of internal stopcock is in middle of house in downstairs toilet.

Mains is 20mm black plastic, reduces to 15mm copper at internal stopcock which then runs through wall, under concrete kitchen floor, feeds outside tap and filtered drinking tap and then passes through water softener feeds kitchen tap and back under kitchen concrete floor to boxing in downstairs toilet all in 15mm copper. It then runs up into the loft increasing to 22mm in boxing somewhere, Where it feeds unvented cylinder and hot and cold feeds to rest of property.

Static pressure - 3.5 bar
working pressure - 2.5bar
flow rate at outside tap 14 LPM
property height 8m
All other outlets flow rate is 8LPM
Baths 1
basin 3
sinks 2
showers with standard heads (15lpm) 2
toilets 3
appliances 3

occupants = 2

showers habits: both shower in morning before work and evening before bed shower durations 10-15mins each

Now I have been in contact with TWS regarding their accumulators and have been recommended MainsBoost MB240 + add on but the cost of this is coming to £2000 just for the units.

I am just wondering if anyone knows of any other companies that do accumulators or if anyone has any other suggestions to overcome poor flow rate for this system?

I was thinking of installing breaker tanks and using negative head pump to supply feed to PRV where I would take balance feeds to house, but would resistance of PRV affect working of pump? Has anyone done it like this in the past?

As as you can tell this is the first time I have had overcome a situation like this and appreciate all the advice you more experienced engineers can offer.

thanks

 

[tolly]

Surely the Mainsboost would be pointless as it charges the accumulator to 3.5bar but your static pressure is already 3.5 bar so it wouldn't help

 

[tolly]

Seeing as the 2 occupants generally only shower, maybe its worth just trying an accumulator.

 

[kris]

Is it possible to run 22mm right up to tank instead of 15 mm. ?

 

[plumb_know]

Hi kris,

Originally customer idea was to upgrade supply pipe and run up to loft in 28mm, but new supply can't be run near existing internal stopcock and 15 runs under concrete floor in newish kitchen. Only way to get 22mm in loft without serious distruption would be to remove softener and have kitchen off as just a spur and property on hard water. But believe incoming mains pipe internal diameter is only 15mm anyway so wouldn't it be bit pointless running 22 with supply pipe internal diameter still only being 15?

 

[plumb_know]

Tolly I'm not sure as this is what TWS recommended on the information I have provided, they said I didn't need the charger as have good pressure? Like I said this is all new to me so am trusting their expertise.

Way they explained it to me was 2 tanks that are under pressure and these 2 tanks can deliver combined flow rate of 30lpm to both showers for total of 9mins. I will copy and past the quote they sent

 

[plumb_know]

Further to your recent enquiry, we now have pleasure in quoting for the supply of the following equipment. The quotation is based on the information supplied and the design criteria noted below;

Position of incoming main
Downstairs WC
No of WC`s
3
Incoming main size
15mm
No of Basins
3
Type of incoming main
Copper
No of Baths
1
Incoming main pressure
3.5Bar
No of Sinks
2
Incoming main flow rate
14lpm
No of showers @8lpm
0
Height of property
7.5M
No of showers @15lpm
2
No of Floors
3
No of showers @25lpm
0
No of Bedrooms
3
No of Body Jets @8lpm
0
No of Bathrooms/En-suites
2
No of other outlets
3
No of Occupants
2A
Water Softener: y/n
Yes
Hot water generator: 210litre Unvented cylinder
Position of Hot water generator: Attic
Position of boosting system: Attic
No of persons to shower: 2 Time Frame:

Notes - design criteria
• Consideration should be given to the position of the TWS MainsBoost unit to ensure sufficient structural support within the loft area.

• The MainsBoost system specified will store sufficient cold water to allow 2 showers with a combined flow rate of 30lpm to operate for approximately 9mins without recovery from the mains supply.



• The MainsBoost system is designed to provide the potable drinking water supply to the property; consideration should be given to fitting MainsBoost tailored insulation jackets to provide protection from Thermal gain and/or potential frost damage.
• Water consumption figures are based on the following average showering times;
Adults: 6 minutes, Teenagers: 9 minutes, Children: 6 minutes



MainsBoost Domestic Water performance system
1No TWS MainsBoost patented water performance system comprising a MainsBoost MB240 WRAS approved water accumulator unit(s) incorporating the patented CAD2 design 100% Butyl diaphragm assembly with copolymer polypropylene liner, stainless steel diffuser and port connection. Each system supplied c/w 22mm upstream line in kit consisting of: 0-10bar inlet pressure gauge, Y pattern strainer, double check valve, pressure regulating valve with gauge, Conex demountable vessel connection; 28mm Full bore lever ball valve. Approvals: NSF Standard 61, CE/PD, WRAS, ACS, ISO-9001.
Standard exterior polyurethane finish: RAL1013 Almond.
Dimensions: 1210mm Height x 535mm Dia.
TWS Product Code: MBD-24022 List price £949.00

MainsBoost Add On (additional stored capacity)
1No TWS MainsBoost Add on Unit(s) comprising a MainsBoost MB240 Unit incorporating the patented CAD2 design 100% Butyl diaphragm assembly with copolymer polypropylene liner, stainless steel diffuser and port connection. Each unit supplied c/w Conex demountable vessel connection; 28mm Full bore lever ball valve.
Approvals: NSF Standard 61, CE/PD, WRAS, ACS, ISO-9001.
Standard exterior polyurethane finish: RAL1013 Almond.
Dimensions: 1210mm Height x 535mm Dia.
TWS Product Code: MBD240AOU​List price £716.00

Optional extras
Tailored Insulation jackets
2No MainsBoost MB240 range insulation jacket(s)
Custom tailored insulation jackets to fit the MainsBoost/ MainsBoost Plus range.
Finish: Grey silicone coated E-cloth.
Product code: MB-240JKT List price £242.00each



• It is the responsibility of the contractor to ensure sufficient site access is available to allow placing of the specified equipment within the designated plant area.


Lead times: 2-3 working days from receipt of order.
Carriage: FOC on 48 hour carrier service to origination of order/branch address.
Delivery to site: £35.00

VAT EXTRA.

We trust the foregoing meets with your approval and look forward to receiving your valued order, in the meantime should you require any further information please do not hesitate to contact the office above.

Yours sincerely,
Martin Coller
Technical Sales Support
​

 

[plumb_know]

Tolly I was led to believe these were accumulators?

 

[Ermintrude]

Could the softner be causing loss? I would be thinking about filled tank of softened water and then BCW pump. Not sure if you can leave softened water for ages tho

 

[plumb_know]

Thanks ermintrude,

customer has bypassed softener in past and it still poor flow rate. Bcw pump? I will look into leaving softened water in tank otherwise I could remove softener and install scale out instead if I was to go down breaker tank route.

Have you installed a megaflo this way before?

Thanks

 

[Rybo_1]

High flow hoses on water softener?

 

[Rybo_1]

Oh sorry missed the post before
mine