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Navien Model 240A

Posted by dreamer16 (My Page) on
Thu, Apr 24, 14 at 10:42

We are building a new house and our builder has suggested this tankless model for heating water for the whole house. The house has 3.5 baths and the plumbing is somewhat spread out. I told him that I wanted instant hot water and he said that this model can provide that. I've seen some bad reviews but many seem to be for the CR model. I believe ours will be the NR model. Would love some opinions on what you think of it....thanks!


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RE: Navien Model 240A

This is a a tankless heater with a circulating pump.

It has the potential to do what you need it to do. However, it still requires reasonable plumbing design. Kitchen, 3.5 baths, and Laundry that's spread out is going to be tough to have "instant" hot water.

Be sure that hot water lines are well insulated, including the circulating return line. This is not just to reduce energy usage on a circulating system, but to reduce "cool down" between uses that would cause you to wait for hot water.

Without seeing your floorplan, I think you should be open to the idea of more than one heater located at different ends of the house.


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RE: Navien Model 240A

Thank you for the response. I guess I don't necessarily need "instant", but I don't want to wait very long. The furthest fixture will be about 50 feet from the tank. Any idea how long it would take to receive hot water if the lines are well insulated?


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RE: Navien Model 240A

The contractor spec'd that heater because it contains a water pump that circulates the water through the pipes - keeping the water hot. How long you wait is completely dependent on how well the system is designed - you could conceivably have very little wait time at that fixture. The problem becomes designing the recirculating system so that it keeps water circulating through all of the branches when a house is spread out.

The big design problem is a large house with plumbing that's spread out. It's not uncommon to see a water heater in a garage at one end of the house and the master bath at the far end. It's incredibly bad design.

There are a tremendous number of other variables, the basic design of the plumbing (branch, home-run, hybrid) the size of the pipes, the length of the run, how often the water is used, and how well the pipes are insulated are some of the big ones.

I don't know your floorplan, etc. but if you are asking about a water heater, this one is one of the most efficient and has a circulating pump to reduce wait times on long runs. One of the drawbacks to a circulating pump is that it will increase your energy use through the heat loss in the pipes... again, so you want to insulate all of your hot water pipes.

All that said, be open to the idea of two of these - at different ends of the house if it's needed.


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