Hi Grant,
Finally got to check the new calorifier this weekend and after running the engine for over an hour, the water was barely luke warm and in fact, no better than the old system we had. I checked the top hose afterwards and although it was hot where it sits near the engine block, it was distinctly cold before it arrives at the calorifier although the bottom hose was very hot. Poss airlock maybe? The yard are going to look at it this week so I will let you know the results later.
Looks like there is little or no circulation but I did notice that instead of the engine maintaining a steady 80 degrees as always, the temp was 90 for 45 mins??
Watch this space!
Jim