Does anyone know why my tankless water heater makes my lights flicker when it's in use?

Question

Everything is connected properly and to specifications. The water heats up fine and I'm saving money. The lights flicker when it is heating water. Nothing else is affected. Any ideas?

Answer 1

If electric you may have an element that is defective.

Could be loose wiring.

Answer 2

Tank less heater draws 10,000 watts or 41.66 amps a lot of power you could have a problem from the pole outside your home to the panel box inside your home, you need a electrical tech to hunt this problem down. It could be the power company equipment.

Answer 3

I would suspect you have low line voltage.  Those on-demandelectric water heaters draw HUGE amounts of power when they run.  You may want to put a voltmeter on the line and see what the line level drops to when that beast kicks on.

Answer 4

You should check to make sure the heater is on it's own breaker and not sharing a breaker with the rest of the bathroom (or half of the house in some cases).  Something that draws that much power should be on it's own breaker to handle the load it creates when it's doing it's job.

Answer 5

Quite possibly a loose connection in the power panel or in the meter. The main buss may be loose and the heavy draw of the water heater is causing an arc.