Arrived to do a performance maintenance. Upon arrival homeowner mentioned issues getting hot water to the house. Found that the pilot to one water heater was not lit. Tried to get the water heater ignited and was unable. Reached out to the plumbing manager for assistance diagnosing the unit. Switched focus back to the furnace maintenance. Set up for combustion analysis temperature split and static pressure tests on each system. Found that the upstairs system is operating close to its overheat limit. Verified operation of all mechanical and electronic components of each furnace. Checked blowers for cleanliness and to see if there is any play in the bearings. Found that the fan for the upstairs system is coated in dust debris. Checked each systems heat exchanger to ensure proper venting of flue gas. Verified operation of the humidifiers. Replaced both furnace filters and humidifier panels with homeowners supplied products. Furnaces and humidifiers are operational at this time. Found that