I've just changed to larger buthane 7kg Calor Gas bottles and bought 2 new regulators ( one as a spare) and noticed that they are marked 29mb. while the old ones were 28mb. A caravan service manual quotes 30 mb. Just to make things interesting I have a very old scrap one marked as 27mb. I can't find any reason for the difference and I'm aware of the 2003 change in new caravans , but will 29mb damage my Carver water heater? or the Fridge?