If by "losing its steam" it's meant that over months it has been putting out less and less steam then perhaps lime deposits on the valve need removal. I would try taking out all the water and putting in a pint of lime remover. Place it upside down to cover the valve opening and shake it every quarter hour a few times. I would then remove the remover, rinse it twice with water and fill and try it out the third time. If this don't work the valve will have to be removed and cleaned. See other post on that.
Warning: do not heat up lime remover.
A Bejarano, January 2011
