I am changing out an old slant Fin cast boiler to a Viessmann boiler and i probably would be doing it anyway but not for this reason.
The owner had the usual person come in to clean the boiler but he took the LWCO and the vent damper from the system, rewired it to work properly, then sent in another tech from their (well known, reputable?) company and put a red tag on it. The utility then gives a period of time to fix it.
They hope to get the work and often do as the homeowner has no idea what is going on. Totally dis-honest, and this is in winter.