My Polti steam cleaner has ceased to work. The cylinder powers-up successfully but the "gun" on the end of the hose fails to produce steam. It seems to me that this is because there is a blockage either on the cylinder at the point where the hose locks in or, alternatively, that the hose is blocked. If I am right, how does one unblock the blockage or, if I'm wrong, what else could be wrong?

Allan Palmer, January 2011