Navien NFC-200 in cascade with NPE-240A

[RemyTCO]

Hello,

I have a NFC-200 & NPE-240A in cascade - all controlled by a Navilink. There are a couple of issues that it seems that I cannot figure out ... The first is that the "Weekly" setting in the Navilink is greyed out - once I have the two units in the Master-Slave configuration. However -It shows there if I kill the cascade. Second - with the schedule set in the NFC-200 (master) unit - I see that the NPE starts recirculating the water (I do have a return line) at the right time - but the burner does not start. It's recirculating the cold water over and over again. IF - I open a faucet while doing that - the burner will start - but since I have the cold water in the recirc. line - it will take forever to make it to the faucet. What Recirc. Interval and what recirc. sampling time do you recommend using? Thank you.

 

[Breplum]

I can’t help, being mainly trained on water heaters NPE series and limited combi field experience.
I am surprised and have never heard of cascading a combi and WH. Do you have that much high GPM useage for DHW or what?

 

[Sponsor]

 

[GReynolds929]

I'm assuming they are connected with a readylink cable and properly set up as master and slave following instructions starting at page 93 of the installation and operation manual. The master is where all settings are made. Slave follows masters programming.