Apologies - I have an unvented hot water system - water cylinder is 290L and boiler is 37KW. I had the mains pipe renewed during building work. Let me know if you need any other information. Thanks
One reason could be the cold water hasn't been taken off the balanced supply.
An unvented has a Pressure Reducing Valve, if your mains pressure is higher than, typically, 3 bar and the tap feed has been taken straight off the mains then it could be at a higher pressure.
There is what's called a combination valve that supplies the cold water to your unvented cylinder. That has a Pressure Reducing Valve in it to limit the mains water pressure that enters the cylinder. At the bottom of that valve there is what called a balanced supply outlet. That allows the cold outlets to be supplied with the the same cold water pressure as the hot.
- they all don't look like this but this is a typical combination valve - the outlet at the bottom is normally used as the balanced outlet.
It's to help certain types of taps/showers that mix the hot and cold water directly in the body, to be fed with the same water pressure, just helps them work correctly.
Your mains pressure can be tested using a pressure gauge attached to say an outside tap or a washing machine valve, anything that isn't fed from the balanced supply.
thanks - very educational. If you have an unbalanced supply can it cause noise problems in the pipes? reason I ask is I get loud banging noises around the area of the taps.
No, I wouldn't say that the banging is due to unbalanced supplies.
It's usually water hammer - the outcome of when a valve closes quickly (is associated with higher water pressure too) and it sends a shockwave back down the pipework, the pipework then resonates especially if it's loose/isn't clipped or touching something and creates a banging/thumping sound.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local