Navien NPE-240A going cold in showers - check valve issue?

Discussion in 'Tankless Water Heater Forum' started by glycoski, Jun 10, 2020.

  1. glycoski

    glycoski New Member

    Jun 10, 2020
    ISSUE: I've recently been having an issue with my Navien NPE-240A sending cold water to my shower after about 4 or 5 minutes. When I first start the shower, the temperature is hot as usual (setpoint at 125 degrees), then a few minutes later, the temperature drops considerably to luke-warm or cool (but not entirely cold). My children have commented that the same is happening in their showers as well at other locations in the house, so that tells me it is not an issue with just my shower's mixing valve.

    INTERVENTIONS: I've been keeping up with the regular maintenance on the Navien as far as yearly flushing, screen cleaning, and vent clearing. A check of these maintenance targets revealed no possible cause for the drop in temperature that I'm seeing.

    I called Navien Customer Service to see if they could help. The rep sort of blew me off telling me that I wouldn't be able to address the issue myself and that I would need to call in a certified Navien Service Technician. He started spewing out that the Venturi probably needs to be assessed and that I'd need to hook up manometers upstream and downstream, possible igniter issues, etc. - things only a certified technician would be able to fix. To be honest, I found him to be condescending and rude. I don't accept that.

    FIX: So, I found the same issue here on this site (thanks mitch22 and HydroAir Joe!). I pulled the check valve out and found that the spring had become mis-aligned and there were a few flecks of dirt around the sealing ring. A quick cleaning with a toothbrush and re-alignment of the spring seems to have done the trick! Now, an 11-minute procedure has my Navien performing as it had been for the previous five years with essentially endless hot water!

    FOLLOW-UP: I have a question...are these check valves so delicate that they should not really be handled very often? I was planning on adding a check valve assessment to my yearly maintenance tasks, but the spring seems fragile and Navien doesn't detail this as part of their maintenance routine. Does anyone see any issues with pulling and servicing the check valve each year?
  2. WorthFlorida

    WorthFlorida The wife is still training me.

    Oct 28, 2009
    Orlando, Florida
    Thanks for your info on the fix. I cannot answer your question, but the problem with companies like Navien is liability. If a service center tells someone how to fix things and that person gets injured, guess what happens? However, the attitude shown show never be especially since you have a good understanding on the unit and seem competent. On this forum I have several times had made similar statements because of the type of questions asked, the person had no idea what he was doing. I don't want someone to electrocute themselves. :)
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