Navien NR-210A Circulation Pump; Remote Display Questions

[kbo]

Hi,
I have a Navien NR-210A water heater installed in 2013. I just replaced the circulation pump and the remote and I have two questions I'm hoping someone can help me with

* In the Service Manual the last step in the instructions to replace the circulation pump is: "24. Open air vent on top of pump to release air.". Both the old and the new pumps have a red cap and I wonder what is that I need to do here: push the red cap up? unscrew the whole vent? something else?
* I had to replace the remote due to a broken display and I want to make sure that everything is OK with the new one/there are no other problems: the display shows the "Recirculation Indicator" all the time (I have internal recirculation turned on) regardless of whether the water heater is actually recirculating or not. All other indicators are displayed only when the corresponding function is active (e.g. faucet is open, etc.). Unfortunately, I don't remember whether this was the case before since the display was broken quite some time ago...

Attached are images of the old pump (the new one is identical) and the remote with the recirculation indicator shown (please ignore the schedule - it will be updated!).

Thank you!

 

[GReynolds929]

Yes, pop the red cap up and run the circ pump to purge air. Once air is purged close the cap. I believe if a recirc schedule is set the icon will always be present. Do you have a manual?

 

[Sponsor]

 

[kbo]

Thank you, @GReynolds929!
I popped the cap and closed it after the pump run. I didn't notice any air coming out, but the cap is in very tight place, I can barely reach it. I tried to feel around the cap, but couldn't feel anything. Is there a way to know that the air was purged?

For the indicator: yes, I have the manual, but there is nothing in it saying whether it stays on all the time or not.

Another question: some of the elbows, e.g. under the flow sensor have a black, foamy tape-like on them and they started to deteriorate and are shedding small black pieces inside the water heater. What is this material and can I remove it or replace it?

Thanks again!

 

[kbo]

Update: I saw that the recirculation indicator flashed while the water heater was in use, so it looks like its behaving differently than the other indicators? I would like to make sure that the replacement remote is not malfunctioning and that this is not an indication of something else.

Thank you!

 

[GReynolds929]

Which remote do you have? NR-10DU is what came with the heater. Newer ones may or may not be fully backwards compatible. Not sure.

 

[kbo]

Both the original one and the replacement one are NR-10DU.

I have a follow-up question about the circulation pump: Is there a way to know that the air was purged? I tried feeling around the red cap, but I didn't feel anything.

 

[GReynolds929]

If it's working and not making unusual noises it fine.

 

[kbo]

Thank you!
This is what I thought, but I just wanted to be sure!