4. MaintenanceRegular maintenance s

4. MaintenanceRegular maintenance should be performed at least once per year or more often if reduction in loadoccurs earlier. A typical maintenance interval is an inspection after every 2500 hours operation time or once per year, whatever comes first.Normal maintenance interval is based on regular gas. If the average sulfur content of the gas is much higher than that of the average regular natural gas (approx. 15 ppm sulphur), more often maintenance might be required. Put the boiler into operation on maximum load and wait until thermal equilibrium.Determine load, fan speed, CO2, CO, Tflow, Treturn, Tflue gas, Measure pH of the system water.In case of fill, refill or top up, please write down amount of added water in the table.Write down the measured values in the table above.Put the boiler into operation on minimum load and wait until thermal equilibrium.Determine load, fan speed, CO2, CO, Tflow, Treturn, Tflue gas, Write down the measured values in the table above.Compare the load on maximum power with the one which was measured during installation of the boiler.In case the load is now 5% lower or less, then there is probably an obstruction in the air inlet, flueoutlet, burner, heat exchanger, fan or venturi.  Switch off the boiler and disconnect from the main power.  Close the gas supply.  Read the installation and maintenance manual. And read all appropriate warnings. Wait until heat exchanger is cooled down sufficiently, before starting removal of the inspection covers.