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System 2000 blinking 145° error

stubingstubing Posts: 7Member
My oil fired system 2000 is (5-7) years old.
It started shutting itself off with blinking 145 error = circulator or temp sensor.
Both have been replaced but the problem persists.
I have had to disconnect the red wire from temp sensor and turn the high temp
control down to 139° to get it to provide heat .
Any ideas on what's going on


  • HVACNUTHVACNUT Posts: 1,589Member
    edited December 2017
    This is an EK Frontier? I wasn't aware there was a 145 error code on the digital manager.
    A 140 error is power was sent to the burner but boiler temp did not increase in 20 minutes.
    Bad circ would cause a 140 also but you replaced it. Correct direction?
    Possible closed or blocked bypass.
    Is the system operating fine from the high limit?
  • dobro23dobro23 Posts: 55Member
    Blinking 140 is a return temp run time error. basically the return water did not come back hot enough in a certain amount of time. (I think it's 20 minutes). to reset the error code on the manager all you have to do is turn off the switch and back on and the burner should start again. Now the important part.. have you ALSO had to press the reset button on the burner itself? if so, THAT is the cause of your problem. not the error 140. if not, then it usually points to a bad circulator. if youve already replaced this make sure its pointed in the right direction ( often times OEM vs regular circulator motor orientations are opposite) on the system 2000 the correct way is that the direction of flow arrow on the circulator is pointed towards the front of the boiler. also give a good purge and make sure youre not airbound preventing flow and make sure youre plate heat exchanger is not plugged or restricted. it's a good place to start.
  • stubingstubing Posts: 7Member
    Thanks, I will check circ direction and check for air. I haven't had to use red button, just off wait 30 seconds then on and it sometimes cycles normally for hours and sometimes (right side) heat light don't come on at all to answer (leftside) demand lights.
    The domestic heat exchanger is an interesting possible culprit. We recently had to stop using it (switched to electric) because of clogging due to water quality issues. I will check to make sure it is still not in the loop.
  • stubingstubing Posts: 7Member
    Sorry I meant to report 140 blinking error. With the red wire disconnected the unit is work with high limit, when it is turned down to 125°, any higher and it runs and overheats the house regardless of thermostat settings.
  • stubingstubing Posts: 7Member
  • stubingstubing Posts: 7Member
    Not sure if it is called a Frontier, this is what controller looks like in Board Service Mode, red wire disconnected.
  • Jim HankinsonJim Hankinson Posts: 87Member
    Sounds like there may be a restriction/blockage in the boiler side of the heat exchanger. The heat will work fine in service board mode because an adequate return temp is not necessary for the zone valves to open. However, the boiler will stay hot so your system efficiency is much less than it normally would be so have someone clean or bypass the HE
  • stubingstubing Posts: 7Member
    Thanks for all of your help. It looks like it was a bad zone valve stuck open. Not sure will see how it goes tonight. Thanks again
  • HVACNUTHVACNUT Posts: 1,589Member
    A stuck open zone valve is not going to throw a 140 error. If it's truly stuck without 24v to the motor, neither the Manager or the burner can see that. I would keep looking or find a certified EK service company.
    Click on the Find a contractor link at the top of the page.
  • stubingstubing Posts: 7Member
    I think the symptom of the stuck valve cause the issue: Too much cooler water after a set period of time trigger the error not the actual electro-mechanical failure. That is how I understood it...maybe I got it wrong. Regardless I will keep an eye on it well as my bill for the circulator and temp sensor both of which didn't need to be replaced.
  • Jim HankinsonJim Hankinson Posts: 87Member
    The sensor will not cause a 140 flash. A failed circ will, however, almost always when the circ fails it just does not run.
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