by pass valve

Hi all.
1)If the heat leak of a CH system is provided by a rad in the bathroom fitted with 2 lockshield valves so that you can not shut it inadvertently, would you still need to fit an automatic by pass valve to your combi if it does not come with it?.......or you only need to have one or the other??

2)When you close the hot water tap, would the pump over run of a combi push the secondary circuit hot water towards the heat leak rad or elsewhere within the combi case?? Thank u 4 your time.

You need to check with the manual as to the bypass requirements.

Most modern combi's have an internal bypass that is normally sufficient providing you don't TRV too many rads.

If you have TRV's on most rads I would advise you fit automatic bypass to reduce noise through the valves.

Some combi's don't have pump overun after DHW usage, the ones that do will push primary (heating system) water around the bypass circuit.

Gasguru said:

You need to check with the manual as to the bypass requirements.

Most modern combi's have an internal bypass that is normally sufficient providing you don't TRV too many rads.

If you have TRV's on most rads I would advise you fit automatic bypass to reduce noise through the valves.

Some combi's don't have pump overun after DHW usage, the ones that do will push primary (heating system) water around the bypass circuit.

Click to expand...

Many thanks.