I've install a heating coil with a radiator trap. After installation, there is no heat coming into the coil. I loosen the cap on the trap and steam flies out. Shut off the cap, everything works fine. However, someone has to loosen the cap every morning after turning on the boiler. I did a search and found a thread with similar condition and someone give suggestion saying loosen the cap and try. Is there a explanation and solution to this? No one wants to loosen the cap and shut it every morning right! I'm new to this, can someone help me out? Sorry about the long post.