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Tankless water heater - not enough water pressure to run it?

5 years ago

Hi guys, I'm hoping someone has some insight on this. I searched the forums but most posts made about tankless water heaters are very old. We just put in a top of the line tankless heater after our regular tank water heater died after 14 years. I assumed it would work well to keep hot water flowing. First, it takes a very long time to heat up, like 5 minutes? Seems long compared to the old system. But that I can deal with. The main issue is we don't produce enough water pressure to KEEP it warm/hot. So it gets warm for a while then goes cold mid-shower. My husband watched the meter and it went cold after .4 gallons used. Not enough for a shower. So the next experiment we did was to turn on the sink and run the water there WHILE using the shower. That worked great. So we figured out it wasn't pulling enough water pressure to keep it providing hot water. Almost like it is TOO energy efficient for its own good. So I ordered a new (high pressure) shower head. Here's the kicker, it works great for me, but I take pretty hot showers. My husband doesn't take quite as hot showers, so it starts going cold for him mid way through again. I am pulling out my hair over this one. Any ideas for me? Is this normal?

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