Would pouring hot water into the drainage pipings of air-con to clear chokage spoils the air-con?

My air-con used to leak every 2 months. The air-con technician explained that it was due to drainage pipe being choked by mould and mildrew. He suggested that we pour hot water to clear the choken drainage pipes. I tried it and it worked. But, will hot water damage the drainage pipe or even the air-con? Plse advise.