I have 2 Intellifin boilers. One had to be torn down and re-gasketted / rebiult last year, now I'm being told that I need to have the other one done. Is this normal for these 6 year old heating boilers? It seems excessive to spend $5-6K every six or seven years to rebuild them. Calls to Lochinvar blamed poor maintenance. I have a PM contract for the HVAC equipment to be maintained according to manufacturer spec. I have seen some of the work being done, ie removing the burner and cleaning it, checking the combustion and gas pressures, ect. Is there more that needs to be done annually?