Navien 240A recirculating line

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Jrv

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New guy here, first post . Had a Navien 240A installed a few months ago and hot water seems to take its time getting to the kitchen faucet. The switch is set to internal and dip 1 is on. A few days ago I called the plumber back and he came out and ran what appeared to be a second line going from the units recirc port to the kitchen hot line. He did set the knob to ext recirc and dip 1 to off and 2 to on, other than that it doesn’t look like he did anything else. Kitchen sink still takes its time getting hot .

Should something else have been done? Should a check valve have been installed somewhere ?

I should also add that after reading some of the issues some are having with this unit I hope I don’t regret going tankless.

Thanks
 

Bannerman

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Have you removed the front cover to confirm for yourself the 2-way valve is set to External and the switch settings are correct? Confirm also the circulation pump is actually running.

Assuming the pump does run, does the return line become hot?

Although the Navien Quick Install Guide does not specify a check-valve is required for an external circulation loop using a dedicated return line, I prefer one to prevent cooler water from within the return line from potentially backfeeding to the open kitchen faucet. Post a photo of the connection under the kitchen sink where the return line is connected to the supply line.

Instead of circulating hot water continuously, Navien offer a Hot Button accessory to activate recirculation from the kitchen only when hot water use is anticipated. https://www.navieninc.com/accessories/hotbutton
 
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Jrv

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Have you removed the front cover to confirm for yourself the 2-way valve is set to External and the switch settings are correct? Confirm also the circulation pump is actually running.

Assuming the pump does run, does the return line become hot?

Although the Navien Quick Install Guide does not specify a check-valve is required for an external circulation loop using a dedicated return line, I prefer one to prevent cooler water from within the return line from potentially backfeeding to the open kitchen faucet. Post a photo of the connection under the kitchen sink where the return line is connected to the supply line.

Instead of circulating hot water continuously, Navien offer a Hot Button accessory to activate recirculation from the kitchen only when hot water use is anticipated. https://www.navieninc.com/accessories/hotbutton


He did take the cover off and I watched him turn the valve and change the dip switches. One thing he didn’t do that I saw mentioned in other threads was do the service menus thing with that P 17 setting, but that is not in any manual I have.
As for the check valve, where should that be installed in case I have to call him back? He didn’t do anything under the sink, it was all done in the basement.
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Bannerman

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The Navien NaviCirc manual specifies on page 10, the appropriate P.17 setting is ON, but NaviCirc is a thermostatic valve utilized when there is not a dedicated return line so the home's Cold water lines are used for the return path for Hot water recirculation. Using Cold lines, the water returning to the WH will never be hot so bypassing the Thermal Bypass would make sense.

You might change the P.17 setting to ON to determine if that will correct your situation.

P.12 is the pump run time setting. The default setting is 20-minutes so once the pump is running, it will run for only 20-minutes intervals so be aware of that.

npe-components.jpg
 

Jrv

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So right now I have a line that goes from my Navien's recirculation connection to the kitchen sinks hot water line in my basement. There are no check valves or shut offs on this recirc line. I have no external check valve on the main cold line coming into to the unit.
I called the installer back and was tryng to explain that I need a check valve in the new recirc line to prevent back flow and a shut off on the line by the unit as well for when I do yearly maint ( I saw on a thread where if there is no shutoff then the recirc line will still have water coming out).
The guy basically said I was nuts. He called back an referred me to a diagram in the manual on pg 24 and said I was hooked up exactly like that and there are no shut off or check valves in the diagram. Im guessing this is something Im going to have to do my self, so I cold use a little help . Where do I put the check valve, which line and where?
Thanks for any help
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Jrv

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Just a follow up - my installer reluctantly came back out to the house and called Navien to ask about the shut off and check valve on the recirc line. Tech support said no check valve is needed, they mentioned I may be thinking of when a Navicirc is installed. There you do need the check valve.
They did say I needed a ball valve on the recirc line at the unit. They also mentioned that during the cleaning process I need to change that that dial to INT recirt to by pass getting solution in the recirc line.
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Bannerman

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Although they may not require a check-valve, I prefer one located where the hot supply line is connected to the return line to ensure no cooler water from the return line can back-feed to the faucet.

This thread was to question why it was taking so long for hot water to arrive to the kitchen faucet even after installing a recirculation return line and programming the appropriate settings for external circulation. You haven't reported if the pump is actually functioning which should cause the supply line to the kitchen to remain hot when there has been no hot water drawn for some time. You also did not clarify if changing the P.17 setting made any difference to the situation.
 

Jrv

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Sorry my bad. Tech support basically told my installer that I was getting things confused. They said you only need to change the P17 setting and install the check valve for the Navicirc. Its not needed for just a recirc line because the unit will sense the water degree change and automatically start the recirculation process. If a check valve was needed it would be in the diagram .

Tech support also said you do not need to by pass the thermal setting (P 17) for a recirc line. My recirculation pump is working and water is flowing. The installer said it is taking time because its a long run in the house. Maybe Im expecting that it should be hotter sooner than it is and Im just wrong.

So basically at this point its installed and all settings are the way tech support agree with so the installer is done.

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Bannerman

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I am familiar with the recommended hardware setup and program settings, but you remained dissatisfied with the amount of time for hot water to arrive. I suggested attempting the setting changes to determine if the arrival time might be more satisfactory. If the settings changes were found to be of no benefit, they could then be returned to default, no harm done.

Setting dip switch 2 to On should have increased the pump speed for external circ. The flow rate is typically sufficient for hot water to be delivered fairly rapidly even when there is a long piping distance. Page 45 of the Installation Manual specifies the setting for Intellegent Pre-heating which you may find beneficial.
 

Reach4

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I am familiar with the recommended hardware setup and program settings, but you remained dissatisfied with the amount of time for hot water to arrive.
What starts the pump? Momentary flow detected?
 

Bannerman

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Recirculation will normally run until shut down by the internal Thermal Sensor sensing the return temp. As the water within that sensor cools, the pump will reactivate as needed. In bypassing the Thermal sensor using P.17, the pump will operate while ignoring the return temp detected.

Recirculation may be scheduled by time presets but when Intelligent Pre-Heating is enabled, a schedule will be developed based on the user's usual usage patterns (ie: hot water needed @ 7:00am M-F so start pump @ 6:52 M-F).

As Schedules do not allow for much variance from routine, Navien offer a Hot Button accessory option which will allow users to activate recirculation by demand. For JrV, a button in the kitchen when pressed in advance of whenever hot water will be needed, will activate the pump for a preset interval so hot water will arrive prior to any use.
 
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