Hi can this adapter be fitted directly to the hot air outlet on the diesel heater. I only seem to have 75mm ducting but a 90mm outlet or does it need to be further away from outlet. Thanks Darren

Thank you for your question. Please can you advise your exact heater model? Connecting this reducer directly to the heater is likely to cause overheating in your heater unit.  If your heater model is not designed to operate with 90mm ducting only then fitting a reducer to drop down to 75mm is NOT recommended. I  In this scenario it would only be advisable to install 90mm ducting directly from your heater to the first permanently opeen 90mm outlet. You could then use this 90mm to 75mm reducer after a Y or T Branch to take warm air to a second outlet.