My gas hot water heater is making a high-pitched whining noise in the evenings. This has happened two nights in a row at about 7pm. No water using appliances had been used, nor had anyone in the house used the shower or tub in the hours before the noise. The first time it happened, I turned on the hot water in the kitchen, and the sound stopped. I thought that was a fluke but tried it again last night. Sure enough, the sound stopped abruptly as soon as the water in the kitchen got warm after I turned it on.
Does anyone know what the cause of this might be and if it is dangerous? The water heater is about 7 years old and it was pre- installed in my manufactured home that was built in 2000.
Thanks in advance for any help, Kim