post #21 of 21

Most UDS designs suggest fitting three 3/4" pipe nipples for the air inlets, you look to be using two, plus with the standing pipework and the elbows, they will severely reduce the airflow that will reach the fire. Try removing the upright pipes and putting the valves straight on to the nipples and giving it a try. It should help the throughput of air, which in turn may help to carry away any steam/condensation that may be stagnating inside the drum.