14 years old, Rheem Classic 90 Plus, Model #, RGRA-7EMAES, ignitor won't start. Heating contractor replaced the inducer motor, preassure switch, made sure intake & exhaust are clear. Determined that the heat exchanger is clogged? Condensation will not drane when furnace is running. Once the motor stops, then water drains. Does this sound like the correct diagnosis?

Not being there it would be hard to say, I`ve never seen a clogged heat exchanger,as for the water not draining that could be fixed I`m sure,did the contractor say what it was stopped up with? That's a new one on me,, sounds like a push to sell you a new unit,, but again I`m not there,to check it out