How will you heat the water without a heating element? Unless you are heating water with a firebox, as in old-school samovar heater, you will have to worry about an electric heater which has a coil and does need power. Some manual-fill boiler lever manual pump espresso machines (e.g., Olympia Cremina) have no electric pumps, but some do for auto-filling the boiler from a reservoir (Londinium, e.g.)
If the OP can open his machine and the cause for steam escape is obvious and fixable, then I would try a fix. Otherwise, search for a new machine. Money put into parts and even more, labor, might be better put toward a new machine with a warranty. Steam escaping is possibly a rupture in a water line somewhere with wetting of the boiler or some other hot surface. It could also be a failure of a solenoid or possibly of the pressurestat with boiler overpressure tripping the steam overpressure valve and boiler overheat safety switch.