Understanding Navien Recirculating Water Heater

RuralOwner

We have a Navien NR-240A installed in new construction in 2012. We are on well water and have a low flowing well. The house is set up with recirculation, though I am not sure where in the house the "T" on the system is located.

We seem to have to run hot water for a long time to get it hot. I've checked the remote controller which seems to show that the system is detecting the flow right away. The recirculation timer is set to operate ever 15 minutes, even though we are often not at the property. I don't hear the heater "fire up" right away when the tap is opened and can't tell if the recirculation pump is running. There are no error codes showing.

We want to reduce waste in using water given our well situation.

Perhaps this is normal--how does recirculation help if the heater is not firing--seems like this would just be sending ever cooler water around the loop. Could less frequent recirculation help? Could there be issues with the heater firing even though there are no error codes?

I hate to pay for an expensive rural service call to have the tech tell me that it is working fine. Appreciate any assistance or advice people can provide here.

Zman

If you can post a picture of your setup it would really help. Their are lots of ways your system may be piped.

Dave H_2

is this recirculation pump just recently installed?
If so, what size/model is it? Typically with tankless water heaters, the circulator needs to be properly sized. So to speak "standard" recirc pumps are too small to get it the water heater to fire.

If it is existing and it has worked in the past, then there may be something wrong with the circulator.

Dave H.

Terry O

You might want to verify if the Navien was installed and programmed for utilizing the "internal" or "external" recirc function.

See link:
http://us.navien.com/Engineers_Features_Benefits/ComfortFlow_Technology/

Larry Weingarten

Hello, You might want to talk with the folks at ACT, 714-668-1200 www.gothotwater.com. They understand systems like this and can help you choose the right pump and control that only recirculates when you tell it to. Research I've seen suggests this will save over 90% of the energy costs associated with 24 hour recirculation, which is essentially what you have. Also, it will get hot water to you quickly... depending on the length and size of branch lines off the recirc loop.

Yours, Larry

rocky_mtn

Dave H said:

is this recirculation pump just recently installed?
If so, what size/model is it? Typically with tankless water heaters, the circulator needs to be properly sized. So to speak "standard" recirc pumps are too small to get it the water heater to fire.

If it is existing and it has worked in the past, then there may be something wrong with the circulator.

Dave H.

If the circ pump isn't producing enough gpm for the flow sensor to recognize, the unit will not fire until a tap is opened and produces more gpm flow. Depending on the pump model, if it's not an ECM pump, you should be able to tell if it's circulating with a simple rotating magnetic pump tester. Grundfos reps hand them out like candy, although I'm sure many other pump manufacturers have them as well.