navien npe 240A Not circulating. Tested and replaced multiple parts. But still nothing.

[Lesschamps]

Hi, I have an navien npe 240A on city water, with a recirculating line. It went through a freeze back in early 2023. I replaced the pump because it was cracked. Ever since then the water in the house takes a long time to heat up and the water pressure seems low.

I recently got fed up with this and started to dive back into the heater. I contacted Navian and they recommended I replace the pb board or the pump. Long story short, I have replaced the pump twice(new one installed yesterday) the PB board, the flow sensor and the control panel on the front. But still I can’t get the flow up.

To test the pumps before I install them I plug them in for a second and can hear them turn on. I don’t dry run them as I know that will damage the pumps.

When I go through the tests settings the GPM is about .2

The navien rep had me bleed the air out of the system by opening the drain coming out of the pump while it cycles through the test. Opening the drain when it is on and closing it off before it turns off. When the drain is open I can see the GPM’s go up to about 1.8.

I have cleaned the filters, and run tests. I get error 438 but then it goes away.

I have run the system in both internal and external settings. Currently it set to external with the first two dip switches on. Nothing improves the flow or gets it to recirculate. I’m at my wits end as there’s not much left for me to replace and I feel like I have done a decent job of trouble shooting. Any help would be great!

I’m happy to call a trained professional if I felt like they would do something different than I’m doing.

Please help.

 

[WorthFlorida]

Does the recirculation pump ever turn on? In the current condition, is there hot water when opening a faucet? If you open several faucets, does the flow rate increase? I assume you have a three pipe system with one for dedicated re circulation. Are there any check valves for the recirculation system. A two pipe system there will be a check valve at the furthest faucet.

Navien 240A recirculating line

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...

terrylove.com

 

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[Lesschamps]

Does the recirculation pump ever turn on? In the current condition, is there hot water when opening a faucet? If you open several faucets, does the flow rate increase? I assume you have a three pipe system with one for dedicated re circulation. Are there any check valves for the recirculation system. A two pipe system there will be a check valve at the furthest faucet.

Navien 240A recirculating line

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...

terrylove.com

I can get it to turn on when I test it so yes it does run. As far as normal operation no I don’t believe it turns on. As far as I know there are no check valves outside of the one inside the hot water heater. Happy to keep answering questions and thanks for the reply.

 

[Breplum]

In my installation manual for NPE A is says for External recirc the dip switches should be 1-OFF, 2-ON. Only dip switch 2 should be ON.
The 2-way valve should be in the down lever position for EXT.
I am trained, but nearly every service visit, I get on the phone with the tech center and they have me do a step by step check if I don't immediately see a problem.
And almost always, pull the check valve. The check valves are failing here after about one year or less. The o-ring swells and caused the check valve to stick open. That's not your problem but I mention it because it is soooo common.

 

[Lesschamps]

This is awesome. I’ll reset the unit so the valve is set to ext(vertical) and make sure dip switch 2 is on. I am willing to replace check valve I was also thinking of replacing the water adjustment valve. What do think of the replacements? I’m just running out of things to check.

 

[Breplum]

Replacements were over the top. But, good work...save the parts bc they may be all still good.

 

[Lesschamps]

Replacements were over the top. But, good work...save the parts bc they may be all still good.

So far I have not replaced the two valves. Only the pump and the pcb board. But I think that was overkill. It sounds like there is no need to replace the parts. But then I am back where I started with a non recirculating heater with a working pump and valves and dip switches set correctly. Open to more ideas!

 

[John Gayewski]

I'm pretty sure the dip switches don't need to be set. As in none of them should be on. The valve for external recirculation should be switched but that's all that needs to be set on the A2.

Your set to "always on" in the recirculation settings?

The only time the dip switches are changed is for propane conversion on the A2.

 

[John Gayewski]

 

[Breplum]

I'm pretty sure the dip switches don't need to be set. As in none of them should be on. The valve for external recirculation should be switched but that's all that needs to be set on the A2.

Your set to "always on" in the recirculation settings?

The only time the dip switches are changed is for propane conversion on the A2.

OP said A not A2

 

[John Gayewski]

OP said A not A2

I don't have one of those manuals, so I'm out of this one.

 

[Lesschamps]

Update. I was taking pics of the dip switches and valve settings and saw some drips. Found that the siphon behind the pump has two big cracks in it. Ordered new siphon. Thinking the cracks are allowing air into the system so the pump can’t create enough pressure to circulate properly. Just a hypothesis but can’t see what else is wrong.

I’ve attached pics of my dip switches and valve settings and recirculating pipe for reference.

 

[Lesschamps]

Welp, I’ve replaced the Syphon and have the dip switche 2 set to on and the valve set to EXT. When I run the pump test I get less than a GPM. Still the same issue with no instant hot water. With this issue being caused by a freeze I am afraid there are other parts I can’t see that are broken. No other signs of leaks in the system. Is time to call a plumber? I’ve had one out before for this specific issue and they did not fix it.

 

[Lesschamps]

I wonder if I should dive into the parameters and try and get the pump to circulate more often. I also am wondering the 240a thinks there is an external pump. Has anyone messed with parameters?

 

[GReynolds929]

The pump should be producing more than 2 gpm when run. I suspect the pump is dead

 

[Lesschamps]

I had the same thought. I replaced the pump 2 times. And when I plug it into the power line to test it, it spins up. So there must be something in the system that tells it not to engage. Thanks though!

 

[GReynolds929]

When you replaced the pump did you open the siphon to release trapped air and make sure the pump isn't air locked?

Has the pump filter been cleaned?

What happens if you set to internal recirculation at the dip switch and 2-way valve?

 

[godbreath]

How do you run a pump test? Is there an internal setting to force the pump to run? My navian is having similar issues.
The hot water return pipe never gets warm so I think the pump may be broken. It has never worked for me since it was installed 3 years ago. The pump itself gets very hot to the touch, but I never heard any noises from it. Hot water takes around 3 minutes to reach my furtherest fixture.

 

[Lesschamps]

When you replaced the pump did you open the siphon to release trapped air and make sure the pump isn't air locked?

Has the pump filter been cleaned?

What happens if you set to internal recirculation at the dip switch and 2-way valve?

I didn't open the siphon after I replaced the pump, I'll have to look how to do that, any suggestions. I did bleed the air out of the pump by running a pump test and opening and closing the drain on the bottom of the pump and the front of the pump many times. When I talked to the tech this was his suggestion as well. I'll try and bleed the air again and see if I can bleed the air out of the siohon as well.

How do you run a pump test? Is there an internal setting to force the pump to run? My navian is having similar issues.
The hot water return pipe never gets warm so I think the pump may be broken. It has never worked for me since it was installed 3 years ago. The pump itself gets very hot to the touch, but I never heard any noises from it. Hot water takes around 3 minutes to reach my furtherest fixture.

I can't remember exactly but you have to hold down one of the two buttons above the reset button( the guy with wrench or i button), I think it is the guy with wrench. Then the letters TST will appear on screen, use plus/minus button to cycle till it says Pump. I think it is #2 after vent, so hit plus once to get there. Once you see pump, hit the i button and you should hear the pump cycle on for about 10 second then off. It will cycle a bunch of times ( I never counted, but It feels like 5 times) afterword it may give you an error code or the gpm of the unit. I would make sure your dip switches are set correctly and the Internal/external valve is set and then run pump test. The pump is about $150 to replace and is relatively easy. You can just replace the motor and leave plastic housing if it is in place which makes the replacement easier. Make sure to bleed the air out. Good luck.