The connection to the regulator is common fir butane or propane but the end that connects to the cylinder is specific to each gas. Do you have a picture of your pigtail connection to the cylinder and the cylinder too.So the issue we are having is that the butane pigtail is 20 mm and the fixing on our regulator is smaller so trying to find a fixing to screw onto the regulator to attach the pigtail but can’t seem to find any answers on the issue
I also noticed that the regulator had been fitted as an in service replacement, (and there are many that have because of the high number of Truma branded regulators which failed. I replace the failed Truma on our last caravan for the same reason).The regulator is a motorhome unit and is a single inlet from the cylinder and single outlet to the appliances.
The other smaller connection is a test point and MUST have a sealing blanking cap fitted to it.
If that cap is missing then the regulator MUST be replaced.
The regulator pictured is not the original regulator , which was a Truma unit, so this is something a previous owner has fitted .