Navien CH-180 won't increase supply temp

[Bathsheba]

Subject says it all: I cannot get the supply temp over 155 degrees no matter what. If I set the supply temp to 160, I get 155. If I plug in the outdoor temperature sensor, regardless of what I set the K curve to I get 155.

I tried changing the DIP switch to set the return temp instead of supply, but this didn't work: it kept showing the supply icon and only allowed me to set the supply temp as before.

As long as it's over 20 outside a max of 155 is OK, but below that my apartment drops into the low 60's and I can't deal...it's only a few days a year, but I'd like this to work. Everything I've read says this boiler should be able to supply up to 180 degrees.

What other factors could be causing this limit? Anything I can fix?

Thanks!

 

[Samat]

Subject says it all: I cannot get the supply temp over 155 degrees no matter what. If I set the supply temp to 160, I get 155. If I plug in the outdoor temperature sensor, regardless of what I set the K curve to I get 155.

I tried changing the DIP switch to set the return temp instead of supply, but this didn't work: it kept showing the supply icon and only allowed me to set the supply temp as before.

As long as it's over 20 outside a max of 155 is OK, but below that my apartment drops into the low 60's and I can't deal...it's only a few days a year, but I'd like this to work. Everything I've read says this boiler should be able to supply up to 180 degrees.

What other factors could be causing this limit? Anything I can fix?

Thanks!

You need to change the main Printed Curcuit Board to get it to 180 degrees. Navien supplied me the board for free but I was under warranty at the time. The unit comes standard with a 160 board. I had to do this on my CH210. They also require that you switch to CPVC exhaust piping which is very expensive.

 

[Sponsor]

 

[Bathsheba]

Thanks, I suppose that's probably what it is.

*sob* I've already had the PCB replaced twice. First time under warranty, supposedly with the 180 degree board, then it failed again.

Is there any way to tell by looking at this board which kind it is? I see one can buy them online, but I don't want to spend $200 and get another of the wrong one.

 

[Samat]

Can’t help you there