Grin, not trying to get around the rules. Just find this rule could be interpreted in different ways.

So for example if the aim is to prevent a valve from freezing up in use different methods could be used;

- bolt the valve to a heat sink of some kind, maybe with some fins.
- Use some electronic heating of some kind which only heats to ambient temperature
- Use heat from other areas to heat the valve through positioning / fans

Two of these would be legal and the other one not, even though they all in effect add heat to the valve / CO2 system.

Other solutions, the cooling comes from the gas expanding and one of the places that happens is where the gas leaves the system, still under some pressure. So using a pipe to allow the system to vent at some distance from the valve area can help. Certainly allowing the system to vent near the valve will cause condensation and freezing to occur to a greater degree.

One final thing (and it may be our imagination), but we switched from getting our pub CO2 bottle which we used to recharge our system, filled at the local welding shop to a fire extinguisher supplier, and the gas seemed to contain less water?!?!