That shouldn’t be the case.
A mega flow won’t necessarily help at all. It only stores the hot water pressurised?
Unfortunately, most plumbers haven’t got a clue how to deal with this and try and sell vastly over specified system that cost a fortune.
Questions 1 - do you have a section of lead water main coming into the house?
You can tell if this is in the old coal cellar by the old appearance and the fact it has lumps and protrusions on it. A modern water main will likely be blue. If you have a lead main get it upgraded.
Hint - check that the stop taps are fully open - it is amazing how many times we find them partly closed. Be very careful not to force old stop taps. This also applies to the valve by the water meter in the street.
Question 2 - does the lead main start from the boundary and only go to your cellar?
Question 3 - how fat is the copper pipe that leads from your stop tap? If it is 22mm then all is good - if it is 15mm that will be an issue.
A lot if plumbers believe, wrongly, that because you have a lead main it is pointless fitting a decent sized pipe. If it is 15mm it will need to be upgraded.
Question 4 - can you test the water flow rate *not* pressure in the cellar. If it is over 30l/min then the problem is elsewhere. You need 15*l/min to run a shower.
Question 5 - what kind of boiler cylinder do you have? Is it a combi (instant hot water) boiler or a cylinder?
Question 6 - what ,in L/min, is the flow rate from the bath taps - fill a bucket and time it then divide. Try the same at the kitchen sink see if there is variation.
Question 7 - what is the best flow rate of *hot* water you can find in the house. Out if a bath tap/kitchen tap etc.
Question 8 - Does one shower output more than 15l/min? If it does then you need to change the shower head to a more eco friendly one. Particularly if it is the lower one this will starve the upper shower.
Solution 1 - Essentially if you have a 22mm pipe Q3 coming from the cellar and more than 30l/min coming into the house Q4 then you can then just fit this mains booster type of pump. It works absolutely fine to give excellent pressure and flow to the top floor bathroom - a joy at kids bath time!
https://www.free-instruction-manuals.co ... 001795.pdf
Personally I’d go for this over the accumulator unless you really need something fancy and have the need to spend an awful lot of money. It will also certainly make the showers usable if the answers to Q3 & Q4 are in line.
Solution 2 - if the incoming flow rate is less than 30l/min then you need an accumulator tank and probably booster pump. This can go in your coal cellar. Again plumbers tend to over specify these things.
The question to ask yourself is how much water do I need to store? If you have X people taking showers Y mins long and the flow rate is Z then you can size the accumulator yourself as it is simply X x Y x Z - also allow for the fact that the accumulator will be fed water all the way through this by the pump.
Also be mindful of what will fit in the coal cellar.
Something like
https://www.anglianpumping.com/product/ ... -c2b-300lv
With this pump
https://www.anglianpumping.com/product/ ... x-60161181
Hint - if you can connect the toilets to the mains before the pressure is boosted - when you flush them at night they won’t be so noisy.
Obvs you will need to get your instsller or supplier to spec the system.
Installation is another matter!
Let us know how it goes.
