Tankless Water Heater Question

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Old 03-08-16, 08:39 PM
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Tankless Water Heater Question

I wanted to spec out a tankless water heater to replace a residential unit to cover a shower/tub, dishwasher, and two bathroom sinks.

What would be an appropriate tankless water heater, hooked up to natural gas, for 8-9 gallons per minute. The part that is confusing me is getting a unit that can heat up the groundwater for a winter in Pennsylvania.

Any recommendations on a brand + model number?

Thanks in advance!
 
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Old 03-08-16, 08:47 PM
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Why do you want tankless?

Average ground water temp is 54f in our parts.. Do the math on the units with temp rise, temp you want the water, and GPM you want...

Plus a unit that size a dedicated gas line is needed as these units are 200k btu or more...

Plus youll get a H/C sandwich effect most likely and may not be happy...

IMO stick with a tank...( Unless there is a valid reason tankless is what you need)
 
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Old 03-09-16, 09:41 AM
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Tankless heaters sound great until you start looking at actually installing one correctly. I'd go with a unit with a tank as well.
 
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Old 03-17-16, 09:25 PM
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Don't need

You don't need a dedicated gas line and there is no cold water sandwich. That is if you know what you are doing. Contact someone who is experienced and trained in tankless water heaters. Dedicated gas lines and cold water sandwhich went out over six years ago.
 
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Old 03-18-16, 02:22 PM
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You don't need a dedicated gas line and there is no cold water sandwich. That is if you know what you are doing. Contact someone who is experienced and trained in tankless water heaters. Dedicated gas lines and cold water sandwhich went out over six years ago.
This is your first post so I am intriged by your statements.. Please clarify .

( Note I am a plumber 30 years)


You don't need a dedicated gas line
So in place of my 40k btu tank heater I can dump a 200K btu tankless in its place? Do you think my 1/2 gas line will support the additional btu's I am adding?

there is no cold water sandwich.
There always has been cold sandwich effect with tankless units that need to heat the water on demand.. The only way to overcome this issue is use of a buffer tank..


That is if you know what you are doing. Contact someone who is experienced and trained in tankless water heaters.
So what do I need to know exactly? To know what I am doing means what? Is there some special way to install these to get them to work with an undersized gas line? Or a way without a buffer tank to stop the cold/hot sandwich effect?

Dedicated gas lines and cold water sandwhich went out over six years ago.
Something must have changed over 6 years ago. Can you tell us what it is that changed, that would allow me to use existing gas line?
 
 

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