Siphon Break Valve - how to test?

[neil1967]

This might seem obvious, but what is the best way to test a siphon break valve fitted between the heat exchanger and exhaust? The pipe from the heat exchanger to the siphon break had built up quite a lot of scale, but the pipe from the siphon valve to the exhaust had none. So whilst I have it all apart, I think it would be worthwhile testing it - but how, preferably without too much mess?

 

[Tranona]

Depends on the design. If it has a permanent water bleed it is either working or not depending on whether water is coming out. If it is a valve that exhausts to atmosphere when it breaks, take the cap off and clean. It should have a rubber valve which makes or breaks the syphon. So if it is clean and not broken it works!

 

[doug748]

If it is of the second type, outlined above, then put the lot together but attach a length of poly pipe to the breather on top. Blowing down this pipe should unseat the valve, sucking should firmly close it. Put the tube in a handy position and you can check, now and again, throughout the season.
These valves can dribble a little which is of no account, the main thing is that the valve unseats easily.

 

[neil1967]

Many thanks - exactly the sort of advice I was after.

Regards

Neil

 

[Ruffles]

I can hear mine vent shortly after the engine is turned off. Sort of a gentle farting noise.

It's the vetus sprung version.

 

[ytd]

if you have the volvo type, don't overtighten it when reassembling after cleaning or it will spew a lot more water. From memory it's about 5ft/lbs torque