Dp transmitter is installed next to the lower tapping point and therefore wet leg is short as possible. In that way we have eliminate boiling of ammonia on wet leg side. Dry leg is significantly long (3.5 m)and as soon as outside temperature is below ammonia temperature we have condensation in dry leg. We are considering two options: 1) To fill impulse lines with suitable seal liquid. Question is what is suitable liquid that will not react with ammonia? 2) To install condense pot below the lowest point of dry leg –depending on the capacity of the pot dry leg could stay dry. Any advices on suitable seal liquid or any other solution?