HOT WATER SWITCHED ON DOWNSTAIRS = A COLD SHOWER UPSTAIRS!!

[boombastictiger]

Hi

We have a problem in our house at the moment. If someone is having a shower upstairs, and a hot water tap or washing machine etc is turned on, all the hot water in the shower goes, until the tap or whatever is using the hot water is turned off.

So if i am having a shower and my mum decides to wash her hands downstairs, ill be having a cold shower until shes finished. We have a normal conventional boiler, which is around 25 years old. We will be replacing it soon, and want to know if there is any way this problem can be countered. We now have 2 showers, 1 upstairs and 1 dowstairs.

Another problem that we are facing is the water pressure in the house. It is so poor for both hot and cold. The shower pressure is really bad especially. How can the water pressure be increased? The hose in our garden has the worst pressure. When only the hose is using the water everything is ok, but when a tap is turned on the hose pressure more or less fades by about 80%.

Please help me as we will be fitting a whole new ssytem soon and would like to know what possiblities and options are available to us before hand.

We have:
4 Sinks
2 Showers
boiler on ground floor
hot water tank on first floor
cold water tank on 2nd floor (atic)

Ill be really greatful for all your help.....

Boombastictiger.

 

[ChrisR]

First it sounds like your garden tap is off the tank - should be off the mains.
Was sure you were going to say you have a combi but no, so you stand a chance! But its impossible to tell without seeing pipesizes, tap types (some may be flashy but designed for high pressure only), etc. A "whole house" pump is one answer but they'e always hard to site.

We could proceed if you measure your flow rates at every tap individually. EG bath tap (off tank system) should be 20 litres/min.

Kitchen H tap shouldn't affect shower THAT much unless pipework is bad.

 

[croydoncorgi]

Simple answer is unbalanced pressure at the shower valve.

Maybe the cold to the shower is straight off the main? Or the pipe sizing on the hot supplies (as has been suggested) is wrong, so that when another use of hot occurs, the available pressure on the hot supply to the shower valve drops. At this point, cold pressure wins and you have your cold shower. The way to test this is to turn the shower to max hot then open a hot tap downstairs. If the flow slows or stops, you need to consider a pump. If it keeps going, a pressure balancing valve on the hot and cold supplies to the shower may be enough to fix it.

Garden tap should be off the main and should have a non-return ('double check') valve in-line to it.