assistancee required please guys

[tom609]

if they have had a new main fitted the water supplier wil test to see what volume of water there is at the boundary that will then tell you where the issue lies there could also be another valve upstream of the stop tap check all the pipework , connect a hose on to the new stop tap and see what flow rates you are getting there

 

[jfb]

I agree with AWheating you should have checked both static and dynamic pressure. However have you installed any isolation valves in the main cold water supply pipe that could restrict the flow. If you have replace them with a fullway valve. Also be careful if you decide to install a pump on the water main, if it pumps more than twelve litres of water a minute you will need to install a breaker tank. Even even though you have replaced the main water pipe this will increase the flow rate but it is not infinite, an average 15mm tap will use about 8litres of water a minute the more you have on the more the dynamic water pressure will drop.

 

[Bronze_tap]

And the problem will go away because the customer will contact legionnaires disease and die. Okay perhaps a bit melodramatic but hot water should be supplied at 50 degrees or more to prevent bacterial contamination, particularly at showers etc. where droplet inhalation is most likely.

I'm afraid there are two problems legionellas breeding inside a typical combi boiler or pipework after it: 1. The water doesn't sit there long enough (20-30 sec max when flowing), and you need at lest 4-5 hours in the favorite conditions for it to become a problem; 2. Usually there is no much nutrients for them in a clean tap water (unlike inside a split air conditioner) + there may be some chlorine/chloramine in there too. Also If your's incoming mains water is full of them, then the typical showering with 65 degrees hot MIXED with contaminated cold water to 39-38 would not eliminate them :-( I'm not sure anybody would like to take UNMIXED HOT shower at 50+ degrees... Legionellas can be a problem if you have an vented HW tank, with the head tank full open and full of dust sitting at 25-45 degrees for weeks. Also the host should have severely compromised immune system (or be 85 years+ of age). Than it is better to take a bath than a shower...

 

[Mike Jackson]

Since when has water only sat inside a combi for 20 -30 seconds? Mine is full of water all of the time and will regularly sit for 8 hours overnight without being used. If the hot water temperature is only set to 40-42 there is a chance of bacteria breeding.

In a typical mixer shower the cold water will enter at less than 20 and the hot in excess of 50. This minimises the risk.

Good practice in the prevention of legionella dictates that hot water in excess of 50 should reach the outlet (or mixing valve) within 1 minute and cold at less than 20 in less than 2 minutes.

Practically the risk may be low but should it occur you do not have the defence of having followed best practice.

 

[SafeGasInstall]

flow restrictors to kitchen sink and send flow to shower .......