A boiler service visit is a set of checks, some tests, and a short written record at the end. This walk-through follows the visit in order. Your job is to clear the way, ask questions, and keep the record. The trade does the work on the boiler.
Before the visit
Find the model plate and the install year, and keep them where the technician can see them. Find the manual if you have it. Clear a path to the boiler and the electrical panel. Note any sounds, odd smells, or changes in heat you have noticed since the last visit. Write them down. Those notes give the trade a starting point and help you check the visit record against what you saw.
Arrival and the first look
The technician should confirm the appointment and the equipment being serviced. Ask them to walk you through the checks they plan to make. Look for a visual inspection of the boiler, its piping, the flue or vent, and any visible leaks. Ask about the condition of the space around the boiler. A short walk with the technician is a good time to ask what they see.
The tests
Expect checks on the burner and gas side, combustion readings where the trade uses them, the water pressure and the expansion tank, the pressure relief valve, the circulator pump, and the controls and thermostat. Ask what each reading means in plain words and what range the trade expects. Ask whether anything fell outside that range and what they recommend.
Cleaning and adjustments
Some visits include cleaning the burner or the heat exchanger, and some include adjustments to the controls or the gas input. Ask which steps are part of the service and which are extra. If a part is needed, ask whether it is on the truck or must be ordered, and whether a second visit is needed to install it. Keep those answers in writing.
The sign-off
At the end of the visit, ask for the written record. It should list what was checked, what was cleaned or adjusted, the readings taken, any parts recommended, and the next service date. Read it before the technician leaves. Ask any remaining questions while they are still there. Keep the record with the install year and the model plate so the history stays in one place.
What to do with the record
File the record with the manual. Plan the next visit from the record, not from memory. If the boiler is in the later part of its typical service life, add that to your notes so any future replacement conversation starts with the full history. The boiler page on this site sets out typical service life and when to plan.