storage tank and L8 issues

[dumbsparky]

pretty much every single wash basin in my building is outside of the legal temps for L8 readings. At the mains the temp is coming in at 16.4c, in the middle of the tank it's 18.3c, but when I go to the closest point and take the temp it jumps up to 25.5c which is obviously a very dangerous temp for legionella to spread. The hot comes out at around 62.5c but i'm slowly adjusting the boiler until it reaches <60c and I have confidence in that so it's not a problem. What I would like some help with is getting the temps down so they are inside the L8 requirements.

Q/ how do I lower the temp of the water so it's <20c? -obviuosly as low as possible would be the best-

Q/ could it be a pump issue? or perhaps the cold pipes are going through a hot spot i.e next to a boiler, is that a resonable assumption??

any help would be great guys as I'm new to this job title (multi skilled engineer) and i'm a sparky by trade so please don't be haters and help me get this done and dusted,

kind regards

Dumbsparky

[AWheating]

if the temp is increasing between the tank and the outlet then its got to be picking up heat between the two. Check pipe routes and lag pipework.

what tpye of system is it?

[dumbsparky]

it's a cold water supply for the wash basin's and cleaners cupboards it feed's 15 wash basin's, 4 showers and about 30 mobile sinks. We are a lab enviroment. I hope this helps im still coming to terms with general terminology as I'm a sparkie.

[Kimou]

The feed to the tank should be on the opposite side of where the down service is. You could install a destratification pump also.

[dumbsparky]

ok thanks very much guys the lagging does look quite old and it is a very busy part of the plant room, I shall make a recommendation to the client as to install new installation and let you know how it go's, thanks very much.

[LegionellaSlave]

Your tank is gaining nearly two degrees so it needs lagging, or maybe you dont use enough water. Pipes could be oversized. The pipework might run alongside heating pipes. Does the tank just supply cold taps?