A steam iron generally produces steam in use as the movement allows water in the reservoir to move around and small amounts will escape into the heated sole plate.
The button to produce extra steam is mostly a small pump similar to those found in trigger sprays and hand soap bottle pumps and this is connected to the sole plate by a small-bore hose. It is far from unknown for one or more of the little hose(s) to become disconnected, often because of a limescale build up - even though the modern steam iron is advertised as needing only tap water, this is suitable only in soft water areas. Irons used in hard water areas tend to have a much shorter life so an alternative is advised.
My description doesn't apply to every steam iron - in some older designs the extra steam button opened a valve in the bottom of the reservoir to allow water to gravity feed into the sole plate. Although almost exclusively found on irons from the premium end of the market they were a nightmare of rods and rubber seals no longer lasting or reliable than those with a cheap plastic pump.
Clearly your iron needs dismantling and repairing if you can do this yourself, or replacing if you can't due to the disproportionately high repair shop cost. Some years ago my wife gave up on premium irons and began to buy the cheapest and was at first happy to replace them fairly often saying she found them no better or worse than the expensive ones. The first couple only lasted a couple of years each but the last one is now six or seven years old and still going strong.
Answers & Comments
A steam iron generally produces steam in use as the movement allows water in the reservoir to move around and small amounts will escape into the heated sole plate.
The button to produce extra steam is mostly a small pump similar to those found in trigger sprays and hand soap bottle pumps and this is connected to the sole plate by a small-bore hose. It is far from unknown for one or more of the little hose(s) to become disconnected, often because of a limescale build up - even though the modern steam iron is advertised as needing only tap water, this is suitable only in soft water areas. Irons used in hard water areas tend to have a much shorter life so an alternative is advised.
My description doesn't apply to every steam iron - in some older designs the extra steam button opened a valve in the bottom of the reservoir to allow water to gravity feed into the sole plate. Although almost exclusively found on irons from the premium end of the market they were a nightmare of rods and rubber seals no longer lasting or reliable than those with a cheap plastic pump.
Clearly your iron needs dismantling and repairing if you can do this yourself, or replacing if you can't due to the disproportionately high repair shop cost. Some years ago my wife gave up on premium irons and began to buy the cheapest and was at first happy to replace them fairly often saying she found them no better or worse than the expensive ones. The first couple only lasted a couple of years each but the last one is now six or seven years old and still going strong.