Garden Railway Forum

Hi, while unscrewing my safety valve, a number of parts fell out, these are the ones i retrieved but im not sure if ive found all of them?



please could you let me know and tell me how to put it back together
Cheers
Joe

You're missing the spring!

ok thanks, once ive found that, how do i put it back together?

I would suggest "under supervision" - you're fairly new to all this and this is something you need to get RIGHT. Also, it will need to be calabrated so getting some help might be a very good thing.

what do you mean by calibrating?

You've got to make sure that the safety valve blows off at the correct pressure, for which you need either a boiler or a source of compressed air, together with a pressure gauge which has been checked against another one. With the valve under pressure, you then need to screw the top down until the safety valve blows at the correct pressure. This is NOT something a beginner like yourself should do, and once you've got it sorted, you should NOT fiddle with it again!

Your locos boiler is called a pressure vessel Joe, and as such has a limit how much pressure it can stand. The safety valve is designed to release pressure at a set point, keeping your boiler from exploding (bursting basically) The calibrating is the setting of the safety valve to lift at the required pressure and is obviously quite critical so after its been dismantled, it needs to be reassembled correctly and be reset very carefully. It really is best not to tamper with it cos it can be both dangerous and very expensive

ok cheers, I will probably get a new one from roy wood as they only cost 9 pounds, do they need calibrating as they are adjustable? or will it come pre set and calibrated?

cheers Joe

By the way the reason i was unscrewing the safety valve was to drain water from the boiler as for some reason all the water wouldn't come out just from the top up valve but unfortunately the safety valve top came of and came apart.

If you tell Roy what loco it's for, he'll set the valve accordingly (and he'll probably reset the dismantled one, too).

If you take the safety valve out again, make sure you unscrew the very bottom of it (but you already know that, don't you??).

If you're keeping the boiler drained because of the low temperatures, getting nearly all of it out will be sufficient.

ok cheers, yeah i was unscrewing the bottom of the safety valve and then the top came of without me unscrewing that bit which makes me think it wasn't set correctly

I've got a safety valve tester, if you want to drop it in the post I'll reset it and make sure it wont come apart again.

Hi Dan, thanks very much for the offer but ive lost the spring for it because it fell apart ,
thanks anyway
Joe