I have recently purchased a 1976 mobile home that has had an Intertherm gas furnace installed around 6 years ago. When the furnace clicks on to cycle for heat (before the fan kicks in), it makes a buzzing sound that continues after the fan comes on and goes off when the unit turns off after satisfying the thermostat. Model no. MGHA-090AAAPQ-05. Any thoughts or suggestions?
You describe a noisy fan relay. It could be because it is old and sticky – so needs replacing, or the voltage is low from bad wire connections – so the wire connections nned to be cleaned and tightened.
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