Today I arrived on site Drain Line Issue:The drain line for the heating system was found to be clogged. Unclogged and flushed the drain line twice. System is now operating. When arriving at the client's property. The client was not in the house. I contacted the client, the client told me that he left the basement door open so that I could enter in case he was not at home. The client explained to me on the phone that I tried to flush the boiler but no water came out of the drain valve. I proceeded to verify the unit. I found the drain line clogged. Unclogged and flush the united unis 2 times. Previously when I was doing the maintenance of the unit a week ago. I found the drain line clogged. I cleaned and drained the unit about x3 times at that time. I recommended to the client and explained that it is necessary to do a steam treatment in this unit to clean the system inside. The client told me that he will tell the office to confirm and schedule the appointment to return to