Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to repressurize a boiler [title] Turn off the power to the heating system. [step] After turning your boiler off, wait a few hours so it can cool. If you don't turn it off and allow it to cool before working on it, you could damage the system or hurt yourself.

Ending1: [substeps] If you're working on any mechanical components, consult your manufacturer's instructions for what to do. [title] Use the correct amount of water to avoid splashing over the work surface. Ending2: [substeps] If possible, wait 4 to 6 hours before working on the boiler after you turn it off. [title] Reach under the boiler and pull out the tray that is concealed underneath. Ending3: [substeps] The simplest way to repressurize a boiler is by turning off the heat. Keeping the boiler shut off is the only way to repressurize it and to have it cool down again at the same time. Ending4: By getting your boiler running again at least 30 minutes before you bring it back to a normal temperature, you can quickly repressurize it. [title] Understand why isolating a boiler can be hazardous.

Answer format: ending1/ending2/ending3/ending4