Arrived on site to perform furnace maintenance on 20+ year old furnace maintenance. Unknown age. Prior to starting Homeowner stated that they have not used the furnace in a very long time and have no need for it. Does not remember when the last time they turned it on was. I cycled system for heat. Upon inspecting heating sequence, the gas valve never engaged and furnace did not kick on all the way. System kept going through cycle but never kicked on. Checked all wiring and made sure everything was connected correctly, still did not kick on. Checked for voltage at the gas valve and it is recieving proper voltage but not engaging. Tried hitting gas valve to see maybe if it was stuck due to it not being used in so long, but had no luck. Informed homeowner of findings and informed could not fully complete a maintenance on the system without it being operational. Discussed the price of the repair, but homeowner ultimately just wants to leave it for now as he does not use it and does not wan