I have a Waterfunace EW042 W to W heat pump, it has been working fine for 3 years now but as of late it has hiccuped a few times. First in noticed the house was cooling off and went down stairs and found the unit in lockout, the FD was on the display indicating a low thermister temp of 15 def F, i reset the fault and the unit fired backup and was working again perfectly for 2 days. I confirmed my loop temperature was a happy 33 deg F. I happen to be downstairs last night and noticed that my buffer tank circulation pump that is supposed to cycle 4 times per hour was running constantly, it had changed to C which is constant. I changed this parameter and it was working properly again. While i was at it i checked my derivative and which i had set to 7 deg diferential was now set at one causing my unit to short cycle or turn on every time my buffer tank dropped 1 deg it would turn on the HP to catch up. Just wondering if my posibbly my control board is starting to go bad or why else would these parameters start to change. Any insite is appreciated. Thanks
I wonder if something happened to reset it to factory defaults such as constant circ pump operation and 30 deg freeze protection. Have you stepped through all the settings to see what else may have changed?
The FD setting after the lockout was still set at CL for closed loop, If this is the factory default then this is possible. Just concerned about the the timeline and multiple occurances of different settings.
May be a couple things going on. I've seen where a refrigerant leak lowers evaporator so much that it sets off the freeze protection even though the loop water is well above minimums. I had one do this and I initially misinterpreted it as a thermistor problem and then a scaling problem. I first confirmed the thermistor reading with another probe and then checked low side pressure - very low. I added charge and all was well, still need to find the leak, though.
Electricity is like the 1000# gorilla, it does what it wants. If the changes in setting were toggled and not set with dip switchs a spike or surge could have taken the control back to factory defaults.
I had a 3:00am thought on this. Does the unit save settings permanently to flash memory, or is the memory temporary with a battery backup? If a battery backup, my thought was that the battery may be going bad, and there was a power interruption.
I got a HP lockout today, for High Pressure. I cleared and it has been running smooth for an hour. If it was really a High Pressure problem on the load side would'nt it keep coming in? Thanks,
@ geome, i did not see any batteries on the control board to power the RAM during an outage. They must be written to memory. Any waterfurnace rep's out there?
Well its been 5 days and no problems with the unit any more. I reset the circuit breaker at the panel and let it stay off for 5 min to completely reset the system. My conclusion is that the power bouncing a few weeks ago started this mess and really just needed a hard reset. Thanks, for all of your help and remember when in doubt just reset your breaker first.
