NPE-210A2 'Descale Mode' in Advanced Menu

[RCY]

I just had a Navien NPE-210A2 installed. In the advanced menu, there is #5. 'Descale Mode' listed after item #4 - Special Operations, however, the owner's manual makes no mention of this mode and doesn't show it in the Advance Menu settings in the owner's manual, despite the message showing to Refer to Owner's Manual. The Owner's Manual only shows up to #4.

Does anyone have any insight into this setting? I'm hoping it does something magical when it's time to descale the unit.

Thanks.

 

[RCY]

So, I tried using the descale mode and it activates the internal recirculation pump (in the A2). I stopped it without digging any further.

Thoughts? Do you think this means that there's no need for an external pump when descaling the heater? Wondering if I can just fill a bucket with vinegar, connect two hoses to the service valves and activate the Descale Mode, and the internal pump will take care of the circulation?

I asked Navien and they avoided answering the question by stating that a professional should descale (despite the fact that the descaling instructions are in the User's Manual).

Thanks.

 

[Sponsor]

 

[Bob1209]

So, I tried using the descale mode and it activates the internal recirculation pump (in the A2). I stopped it without digging any further.

Thoughts? Do you think this means that there's no need for an external pump when descaling the heater? Wondering if I can just fill a bucket with vinegar, connect two hoses to the service valves and activate the Descale Mode, and the internal pump will take care of the circulation?

I asked Navien and they avoided answering the question by stating that a professional should descale (despite the fact that the descaling instructions are in the User's Manual).

Thanks.

 

[Bob1209]

You are correct. No mention of the mode in the install manual. But it does allow one to do the descale maintenance without the need for a separate portable external pump. Using this mode will use the internal pump of the unit. The run time can be adjusted on the screen.

 

[Fitter30]

m.youtube.com/watch?v=hOqKn2Eystg

 

[BenT123]

It's so easy with the build-in pump that I clean mine twice a year. Here's how I do it:
1. make sure that red cap on top of the pump is screwed down and pump valve is set to EXTERNAL (pointing down)
2. turn off the power
3. close inlet and outlet valve
3. hook up two g1/2 hoses on the inlet and outlet (doing so will only work on A2 model) and route both hoses into a bucket. If you have recirc line - close the valve
4. open valve to the hose on the outlet side
5. I open the valve to the hose on the inlet side
6. open cold water slightly to fill up the bucket with water, add 1lb of citric acid to 1gal of water, add surfactant (I use a household cleaner with octly/decyl glucoside)
7. turn on the Navien
8. turn on the descaling mode
9. open inlet valve slightly to prime the pump if needed, then close it
10. both inlet and outlet valves should be closed and water circulating in and out of the bucket via hoses for the duration of the descaling program

 

[coolgreany]

I contacted Navien Support about using that function for regular maintenance and here's their response.

You can but typically it is advised to use a flush kit with an external pump 1/8hp and to run the descaling process for roughly 45 to an hour at least. Flow aide as the video started would be perfect to use. The built in descale is for quick descaling in case the unit has a blockage.

 

[BenT123]

...

"The built in descale is for quick descaling in case the unit has a blockage."

I am surprised this was their argument against using the internal pump since flush timer menu goes up to one hour, which is plenty for a regular flush, and if there's a blockage I would rather use external pump since it's more powerful and would not want large sediment go through circulator's impeller .

My guess is that they don't want owners running the build in circulator dry which is certainly possible.

 

[Fitter30]

I am surprised this was their argument against using the internal pump since flush timer menu goes up to one hour, which is plenty for a regular flush, and if there's a blockage I would rather use external pump since it's more powerful and would not want large sediment go through circulator's impeller .

My guess is that they don't want owners running the build in circulator dry which is certainly possible.

Chemicals dissolve the minerals and puts them in suspension there are no chunks. When you descale your heater find anything other than similar to grain of sand?

 

[BruceZ]

It's so easy with the build-in pump that I clean mine twice a year. Here's how I do it:
1. make sure that red cap on top of the pump is screwed down and pump valve is set to EXTERNAL (pointing down)
2. turn off the power
3. close inlet and outlet valve
3. hook up two g1/2 hoses on the inlet and outlet (doing so will only work on A2 model) and route both hoses into a bucket. If you have recirc line - close the valve
4. open valve to the hose on the outlet side
5. I open the valve to the hose on the inlet side
6. open cold water slightly to fill up the bucket with water, add 1lb of citric acid to 1gal of water, add surfactant (I use a household cleaner with octly/decyl glucoside)
7. turn on the Navien
8. turn on the descaling mode
9. open inlet valve slightly to prime the pump if needed, then close it
10. both inlet and outlet valves should be closed and water circulating in and out of the bucket via hoses for the duration of the descaling program

I am getting ready to descale my NPE 240A2 and want to use the internal pump. From my research I concluded that to do that I needed to connect the hose to the recirculation inlet port rather than the cold water inlet port. Is this how you did it or did you use the cold water inlet port and were still able to use the internal pump? Thanks.