Combi help + identification

[timmyquick]

I have a combi boiler which has been cutting out when heating is on for a period of time, so i got the manual out and been studying it as i swear it was a dodgy install. as when i changed the bathroom it was only 15 mm pipe to the hot tap and this is all the way from the boiler. anyhow it says in the manual as recomendation to fit a bypass vavle between the feed and return on the central heating side to stop cutout of the boiler if you have a few radiators turned of and this seems to decsibe my problem so can someone tell me if this pic below is a bypass valve as it does not look like any one i have seen on the net.

 

[ollski]

sure looks like it if those are your main flow and return...it may need balancing though.

 

[timmyquick]

ollski

Yes they are the main feed and return for the central heating. Thanks for the reply i notice that the valve in the pic has i little screw i assume for controling how much water can and can not pass through. Should i try to ajust this? or try to balance my radiators first? though i have noticed all my rads get pretty hot evenly.