New York 5 series error E5

Discussion in 'Maintenance and Troubleshooting' started by Colton Weber, Feb 4, 2023.

  1. Colton Weber

    Colton Weber Member

    I have a waterfurnace 5 series 3 ton unit on an open loop system. I have 2 wells that it utilizes. Pulls from drinking well and dumps back into the empty well.
    Well is only 24ft deep but has tons of water I have never had an issue with flow.

    When it gets very cold, like today it is -15 (windchill it is negative 30deg out) the thermostat will turn red and I get an error E5 freeze detected FP1.

    This has happened every winter since the unit was first installed about 3yrs ago.

    Any ideas what causes this and how to fix it? Is it an install error? Or is the unit just working 2 hard because of outside temps that it freezes up?

    Tap water temp is at 46deg currently.
  2. bpsmicro

    bpsmicro New Member

    I just repaired the exact same problem. TLDR version is that mine appeared to be a bad FP1 sensor. We have a temp fix in while we await the new sensor. But during troubleshooting there were some other things checked. I was fortunate in that I had separate temperature sensors on my in & out lines, so I knew it wasn't actually freezing.

    First thing to check is the filter on the line going in. Make sure it's not clogged up. But there's really no easy way to determine your actual flow rate. The technician in my case had a special tool set that monitored outgoing pressure (from which he could calculate actual flow rate) and the in/out temperatures. Mine were in spec, which pointed to the sensor.

    One thing you can do is, while the system is idling, clear the code and wait for it to kick into Stage 1. See how long it takes to trip the E5. Does your system kick into Stage 2 during this time frame? If it's a flow problem, it's probably a problem cropping up after the system has been running for some period of time, and not so much temperature-specific.

    My original suspicion (now disproven for me) is that while the incoming well had no problem supplying the required flow, I worried the outgoing well didn't have the capacity to take that much and was producing back-pressure. But there's really no easy way to measure that without the special tools.

    Just a note that last night it went down to -34C, and we've been close to that for 48 hours, and my system has been flawless. Not even having to kick into Stage 2. Mind you, we're super-insulated, which helps. But the system *can* handle temps these cold no problem.
  3. SShaw

    SShaw Active Member Forum Leader

    The recommended flow rate is 1.5-2.0 GPM per ton. If your EWT is less than 50F you would need the maximum water flow. Your issue could be related to insufficient water flow.

    I believe the FP1 sensor measures the refrigerant temperature not the water temperature, so you could get the error with incoming water at 46F if the flow was too low.
  4. bpsmicro

    bpsmicro New Member

    That's what I was told. The FP1 sensor is mounted to the compressor itself and is measuring the refrigerant. In our case the EWT is just over 10C (50F), When running in Stage 1 the exiting water temp is 7.5C (45.5F) and FP1 goes as low as 6C (43F). While I don't have the exact number for the low rate, I was told it was "in spec", But it's calculated because there's no actual flow-rate sensor in the water line.

    I ended up setting up one of these on a Raspberry Pi (I already have a Home Assistant automation setup):
    A bit nerdy, but it tells me everything the AID tool does (in a read-only format for safety), and is educational. I just wished I'd gotten the options for more sensors in the WF5 itself.
  5. SShaw

    SShaw Active Member Forum Leader

    I'll have to check out that RPI package. I've got a couple RPIs around.

    I assume you are referring to the refrigeration monitoring package. I've seen that listed as a retrofit accessory kit, so you might be able to add it.

Share This Page