DIY Doctor UK DIY Forums

hi, im busy fitting my own central heating pipes and radiators ready for my combi boiler. im doing a 2 pipe flow and return system and ive been told i need to fit an auto bypass valve. is this true and if so where and how is it fitted? what pressure setting and so on.
any advice much appreciated.

Thanks Chris.

an automatic bypass valve ensures optimum flow rate from your boiler if you system is fitted with TRVs. as TRVs around the house close in response to temperature levels it can cause an imbalance of pressure across the system. the auto bypass valve compensates, taking some of the strain away from the boiler and pump.

as you are installing a new system from scratch then you may as well put one in - assuming that you are using TRVs? the easiest place to put it is usually close to the boiler and it will bridge the flow and return.

for exact siting and pressure setting you will need to follow the manufacturers instructions. depends on the size of your system and other factors so cant really comment without sight of the job.

Thanks for your comments Chris, all rads are fitted with trv's so i best fit the auto bypass. Thanks again.

Hi, I am wondering how you got on with this? I have a problem with my heating system and it has been suggested that I need to install a bypass.

What did you do and what type of valve did you fit?