Navien npe-240s pm

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ratsandtats

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Please note this is for 1 slave in an 8 unit cascade system. None of the units are currently pmable. Same problem with all.
I have everything hooked up, pump running with vinegar through cold iso valve, nothing coming out of hot iso. Any ideas or help is greatly appreciated.
 
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ratsandtats

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Were you getting water out of the unit before you started the cleaning ?
Unit works fine when powered on. Seems to me like something is set to make its flow valves ‘normally closed’ when no power to avoid cold water entering the rest of the system. Gonna edit original post to include its an 8 unit cascade system and this is a slave. None of the 7 slaves are pmable currently
 

Twowaxhack

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If you’re getting water out of the unit when operating then that means there’s no obstruction in the heater.

Check to make sure your isolation valves are working properly and your pump works.

Double check the cleaning procedure in your owners manual.
 

ratsandtats

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If you’re getting water out of the unit when operating then that means there’s no obstruction in the heater.

Check to make sure your isolation valves are working properly and your pump works.

Double check the cleaning procedure in your owners manual.
All thats been done and redone. A valve is closing internally somewhere for some reason when power is off.
 

ratsandtats

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I did call tech support and I've never had better. You cant pm a cascade system in cascade mode. What i thought but had no idea how to change programming-thats where tech support shined. A shame the 5 state master plumber that came to teach me yesterday didnt bother to show me that (or do it) while he was teaching me yesterday…..


Thanks for trying to help.
 

Twowaxhack

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I did call tech support and I've never had better. You cant pm a cascade system in cascade mode. What i thought but had no idea how to change programming-thats where tech support shined. A shame the 5 state master plumber that came to teach me yesterday didnt bother to show me that (or do it) while he was teaching me yesterday…..


Thanks for trying to help.
Glad you got it figured out, Navien tech support is some of the worst I’ve ever experienced.
 

havasu

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When I had my Navian installed, a tech actually came to my house and worked with the contractor to get my system dialed in perfectly. It did help that their manufacturing plant was 30 miles from my house.
 

Twowaxhack

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When I had my Navian installed, a tech actually came to my house and worked with the contractor to get my system dialed in perfectly. It did help that their manufacturing plant was 30 miles from my house.
What did they have to do ?
 

havasu

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Their biggest concern was gas pressure and used a manometer to verify. They made sure all bypass lines were connected properly, adjusted the remote, which was in another room, and verified the recirculation system was plumbed correctly. This was my contractor's first TWH install, and he was really a disbeliever until the tech built his confidence up. This was in 2009, when Navien was looking for design improvements and also looking for feedback, so it was a win-win for me.
 

Twowaxhack

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Their biggest concern was gas pressure and used a manometer to verify. They made sure all bypass lines were connected properly, adjusted the remote, which was in another room, and verified the recirculation system was plumbed correctly. This was my contractor's first TWH install, and he was really a disbeliever until the tech built his confidence up. This was in 2009, when Navien was looking for design improvements and also looking for feedback, so it was a win-win for me.
Gas pressure problems are the biggest issue I find with tankless.
 
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