The automatic bypass valve (ABV) is suitable for all heating systems up to 10 bar static pressure where a boiler bypass is required or where thermostatic radiator valves (TRV) are installed.
The ABV provides a simple method of ensuring adequate flow through boilers which require a bypass as well as reducing system noise.
In systems fitted with thermostatic radiator valves, the ABV opens automatically as the TRVs or zone valves start to close and the resistance of the systems starts to exceed the preset pressure of the ABV.
Technical Data:
Working Pressure: 10bar max
Working Temperature: 100℃ max
Capacity: 1-5m3/h
Connection: 22mm compression
Range: 0.1-0.5 bar differential Pressure
Automatic Bypass valves perform two functions:
. As a boiler bypass as required by the boiler manufacturer.
. As a system bypass to accommodate pump overrun and to alleviate system noise that can be caused by increased pressures when TRVs or zone valves start to close.
Setting:
The valves can be manually adjusted from0.1 to 0.5 bar.
The flow chart shows the flow curve for the individual settings. A setting of 0.2 to 0.3 bar is sufficient for most common installations.
ldeally the pump curve should be plotted onto the chart to indicate the correct setting.
When the Delta P of the pump is unknown, setting the ABV is accomplished as follows:
. Set the bypass valve to 0.5 bar
. Open all radiator valves including any zone valves present for the control of hot water cylinders or other heat sources.
. Ensure the pump is set correctly to adequately heat all of the system demands.
. While the system is heating at full capacity, gradually turn the adjustment knob of the bypass valve towards 0.1 bar until you begin to feel the outlet pipe from the bypass valve begin to feel warm.
. Once this heat is felt, turn the setting back towards 0.5 bar by half a turn to prevent constant flow.
. The valve will now only begin to bypass when the various TRVs and other variable control devices begin to close in response to room/zones temperature increases,
. One at a time, slowly close the TRVs and recheck for system or bóiler noise. If excessive noise can be heard slowly decrease the setting on the bypass valve until it stops.