Question

1. a leak in the condensate return piping:

image of rusted pipes
○ may allow water out of the boiler

Explanation:

A leak in condensate return piping would allow water (condensate) to escape from the piping system. The option "May allow water out of the boiler" is incorrect as the leak is in the return piping, not the boiler itself, but if we assume the option is about water escaping the piping (maybe a typo in the option text), the logic is that a leak in piping permits fluid (water) to exit.

Answer:

The correct option (assuming the option text has a typo and refers to water out of the piping/condensate system) is the one stating "May allow water out of the boiler" (though technically the leak is in the return piping, not the boiler, but it's the only option about water leakage). So:
The option (e.g., if it's the only option with water leakage logic) like "May allow water out of the boiler" (with the understanding the leak is in the return piping, so water exits the piping, maybe the option has a wording error).