I have a mares prestige octopus. Noticed if I give it a shake there is a rattle. If I just put the slightest pressure on the purge button and shake, no rattle. It works fine. Haven't noticed if the rattle is present while pressurised.
It is almost brand new. Any ideas?
Thanks!!
The sound you are hearing is most likely the demand lever, if so it's nothing to worry about. It "may" however be set too low. Having said that it's hard to be definitive over the Internet. Can you take it back the shop or a shop and have someone look at it for you to be sure?
1+.
Short answer 
: Your Prestige is probably normal.
Long-winded answer :blinking:: Most Mares 2nd stages, when properly tuned, will rattle slightly if you gently shake them
while the regulator is pressurized. What you are hearing is the tip of the demand level tapping against the diaphragm. It is normal for there to be a very tiny amount of "slack" for these particular 2nd stages. There should
not be any tapping or rattling when the regulator is
depressurized however.
The reason the rattle stops when you slightly depress the purge button is that it takes out the slack and brings the diaphragm into contact with the lever.
How much slack should there be with the regulator
pressurized??
- The should be a slight rattle (like lightly tapping a fingernail on an empty aluminum can). Not a loud clacking.
- Pressing the purge button should produce an airflow after the purge has traveled about 2mm, but not much more than this.
- There should never be any rattle with the reg depressurized. This indicates a demand lever that is WAY too low.
The reason for a tiny bit of "slack" is to reduce the possibility of free flow in a strong current. If the demand lever is so high that it contacts the diaphragm with the regulator pressurized it will make the 2nd stage overly sensitive.
The reason too much slack is a problem is that it delays beginning of airflow as you inhale, and taken to an extreme will limit the overall travel of the demand lever, making the 2nd stage breath poorly.
If you have doubts certainly get the reg checked, but what you described sounds "normal", and is exactly how I tune my Mares 2nd stages when I service them.
Best wishes.
