Is my cylinder big enough for a pump?

[billystar]

Hello,

Great site, lots of information, hopefully someone will be able to help me.

I have a 1 bed top floor flat with gravity fed water system, hot water cylinder in the airing cupboard. I currently have adequate water pressure with a flow rate of 5.2 litres/minute.

I have a 166 litre cylinder (at least from my basic measurements) and wanted to know if this was a sufficient size to support a 1.5 bar pump to give better pressure for showering?

My partner and I have a ten minute shower each in the mornings and so currently that would use 104 litres of hot water. or 2/3 of the tank.

The figures I am seeing online for a 1.5 bar pump are a flow rate of 10-15 litres per minute. At an average of 12.5 l/m that only gives 13 minutes showering time from a full tank so not enough for our usage.

Is my maths right? Or do you think the 166 litres tank will suffice?

Cheers,

Will

 

[Hugh Jaleak]

You need to consider the size of the cold storage cistern firstly! The cylinder is supplied from the cold storage cistern, and depending on the capacity of that cistern will determine how long you get before the water runs out!

Any mixer shower will be taking its supplies from the hot and cold storage, so the shower is ultimately drawing all the water from the cold storage. You may have a limited cold storage capacity in a flat, so supplies could run out pretty sharpish!

 

[dcawkwell]

lets assume the cold water tank is refilling at 4 litres a minute and
you are drawing it at 11 litres a minute. A short fall of 7 litres a minute.
Therefore your cold tank needs to be at least 70 litres for a 10 minute
shower. The time to refill will then be 17 minutes before the next shower.