propofolboy
New Member
Hi everyone, first post here. Maybe someone can help me.
I have a Navien CH-240 unit manufactured in 2010.
It has functioned well. The siphon started leaking so I got a plumber in to replace the siphon and well he was in we changed the DHW flow sensor pre-emptively. Easy replacements.
When we replaced the cover and tightened it up I started getting error 12 (flame loss) intermittently. We discovered that this only occurred with the case screwed tight. As long as the front case was left on loose it would obviously suck some air in around the case and it would never get an error 12. The problem was air starvation.
We examined the air intake vent. Its about a 30 foot run of 3" pipe, with one 90 degree elbow and a 45 angle, so well within the 100 feet allowed. With a scope it was completely clear of obstruction. The air intake filter was clear with no debris. There was no flue gas recycling (they are well separated). With the case on but not tight I can feel a good draw of air into the unit.
In my googling I have noticed many people have been troubled by intermittent error 12's, and some describe functioning well with the case off but not on. I also read someone describe that the Navien can 'learn' its operating conditions, including air intake so this can be calibrated..
We are at a loss right now for what to do. Everything seems fine, and it functions flawlessly with the case on but not tight. As soon as we tighten it it can't pull enough air via the intake. Anyone have any suggestions??
I don't want to start just replacing parts (PCB, fan motor, etc).
Thanks.
I have a Navien CH-240 unit manufactured in 2010.
It has functioned well. The siphon started leaking so I got a plumber in to replace the siphon and well he was in we changed the DHW flow sensor pre-emptively. Easy replacements.
When we replaced the cover and tightened it up I started getting error 12 (flame loss) intermittently. We discovered that this only occurred with the case screwed tight. As long as the front case was left on loose it would obviously suck some air in around the case and it would never get an error 12. The problem was air starvation.
We examined the air intake vent. Its about a 30 foot run of 3" pipe, with one 90 degree elbow and a 45 angle, so well within the 100 feet allowed. With a scope it was completely clear of obstruction. The air intake filter was clear with no debris. There was no flue gas recycling (they are well separated). With the case on but not tight I can feel a good draw of air into the unit.
In my googling I have noticed many people have been troubled by intermittent error 12's, and some describe functioning well with the case off but not on. I also read someone describe that the Navien can 'learn' its operating conditions, including air intake so this can be calibrated..
We are at a loss right now for what to do. Everything seems fine, and it functions flawlessly with the case on but not tight. As soon as we tighten it it can't pull enough air via the intake. Anyone have any suggestions??
I don't want to start just replacing parts (PCB, fan motor, etc).
Thanks.