Tankless hot water pressure is terrible

Old 03-01-15, 11:28 AM
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Tankless hot water pressure is terrible

I have a Burnham V8H oil boiler that was installed roughly 5 years ago. It is a tankless hydronic system. I have have well water. My cold water pressure going all the way into the boiler and coming out of the faucets is superb. The hot water pressure is just terrible. The more faucets I turn on the worse is gets. I have one zone. I have no issue with the heating system. It's just the sink faucet, shower and tub, bathroom sink and washing machine. All horrendous hot pressure. I have changed out faucets, cut out and replaced copper pipes from and to the boiler as well as replaced several of the ball valves. I also had a new mixing valve put in about a year ago but I have had these issues for a few years now. Any ideas? I am going crazy with this.
Old 03-01-15, 11:49 AM
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Welcome to the forums.

You had a new boiler with tankless water heater installed 5 years ago.
Was the hot water flow good back then and did it get slower gradually or all of a sudden ?
Old 03-01-15, 01:00 PM
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Most common is a plugged coil do to mineral build up from your well water.
Old 03-01-15, 02:29 PM
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What Tom said. Been there, private well.
Old 03-01-15, 02:34 PM
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You are mistaking volume (flow) for pressure, they are NOT the same. You have low VOLUME (low flow rate) and THAT is caused by the tankless coil being restricted by the build-up of mineral deposits.

You MIGHT be able to "boil out" the coil with an acid solution although that is normally not a DIY project and often not all that successful. Your best bet is to install a separate water heater and abandon the "thankless" coil as it is the second worst method of heating domestic water that has ever been devised.

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