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Help with laars Endurance EBP 175

Can someone help me with a Laars Boiler.
First no hot water. Replace flow switch. Same problem. F-4 code. Replace supply sensor.
Refill unit with water.. start boiler. Lots of noise. High pressure. Pressure valve release with lots of steam and shut down. No codes. Check and found pump not working. Replace pump. Start unit up. Unit run for 5 minutes and shut down. No codes. Found power strip. Reset start up and run until unit say 161 and go into sleep. After 2 minutes. It start up again run until it say 161 and shut down. No codes. Help.

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970
    edited November 2022
    I believe the 161 you are f=referring to is the boiler water temperature. If that is true, the normal sequence of operation for the combination heat and hot water EBP will stop the gas flame at 158° if there is no call for heat.
    from page 22 of the manual:
    The EBP modulating combination boiler will
    start from any of three input signals: (a)T-T closure
    for space heating. (b)A demand for domestic hot
    water, signaled by water flow activation of the water
    flow switch. (c)A call for heat from the minimum
    tank temperature sensor at 158°F (tank charge mode).
    In tank charge mode the red LED located below the
    green LED on the PCB will be lit. In modes (b) and
    (c) which are priority modes, the internal anticondensing valve will be closed. On a T-T call for
    heat the valve will remain closed until the priority
    modes are satisfied


    In this mode if there is no call for heat, the system will cycle on the limit temperature of 158° (and possibly over shoot to 161°) until the water tank is charges with hot water and the hot water priority is satisfied.

    If there is a call for heat, the tank must be charged until the hot water priority is satisfied, then the space heating can commence.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • hot_rod
    hot_rod Member Posts: 18,218
    Sounds like an air lock in the boiler. How are you purging it when you refill?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970
    do you have the manual? the trouble shooting is in there. https://www.parts4heating.com/v/vspfiles/images/pdfs/EdpEbpManual.pdf
    A couple of things that may still be wrong
    Can you confirm that your system is properly piped and that there is no air in the piping system?

    OR


    These piping arrangements use a system circulator(s) for space heating. They do not utilize the internal Boiler circulator for space heating.
    Is (are) the system circulator(s) operational?
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • ArchimoreHorie
    ArchimoreHorie Member Posts: 23
    Thanks for responding. I have this system from 2004. Piping is ok
    I have pipe running up stair to get hot water. Hot water run for 5 minutes and go off and comes back on again for 5 minutes.
    Heat is on. Boiler is cycle every 5 minutes.
    I bleed the coin valve two of them. I then bleed the heater line.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970
    edited November 2022
    @ArchimoreHorie OK then there is heat getting to the radiators? Yes or No
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • ArchimoreHorie
    ArchimoreHorie Member Posts: 23
    Yes
    But i believe the boiler is short cycle. Why the hot water is getting cold
  • ArchimoreHorie
    ArchimoreHorie Member Posts: 23
    Heat is getting to the base board ok. Circulating pump is working ok
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970
    Good. the problem is in the priority on the DHW. Let me look at the manual for a possible cause.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970
    One cause could be the flow switch. This switch lets the boiler control know that there is hot water being used. the control goes into a DHW priority mode and stops space heating and also uses the internal boiler circulator pump to take heat from the boiler and direct it into the DHW heat exchanger. If the flow switch drops out during the use of hot water. the boiler control will thing the hot water was turned off and direct the boiler hot water to space heating or shut down the burner if there is no call for heat. It sound as like the 5 minute short cycling is happening during a "no call for heat" situation so the burner stops. then it has to go thru the start up sequence to relight.

    Still checking for more. don't order the Flow switch yet.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970
    edited November 2022
    Two other possibilities for short cycling. Contamination of flue gas into the combustion air inlet. this is for Direct vent systems only. Does your system have 2 pipes to the outdoors for the venting. Or the concentric vent where both pipes go thru a bigger opening?
    Example of concentric vent:
    If one of the exhaust pipes has a leak and the exhaust is getting into the combustion air intake, then you get this cross contamination that can cause short cycling.

    Look for a damaged vent pipe. inside and outside

    The other one is the anti condensation valve on the EBP models may be stuck. it is #17 0n thei illustration Try tapping on this with a small hammer or a wooden mallet for tenderizing meat.
    Be firm but gentile. If that corrects the problem, then order this kit:
    VALVE, ANTI CONDENSING, REPAIR KIT 2400-538
    If the vent leak (could not find a vent leak issue) or the anti condensing valve (tapping on valve does not make a difference) are not the problem then you probably need the flow switch.

    I would order both the flow switch and the valve kit if I was in your situation. Since both require draining the boiler, then is would do both at the same time.

    Disclaimer: The last time I worked on one of those was 2011. My memory on this product is limited to only 2 different customers. Neither had your issue.

    I hope this helps



    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • ArchimoreHorie
    ArchimoreHorie Member Posts: 23
    edited November 2022
    Ok. New flow switch. I have two vent pipe. One of the vent pipe that fix on the burner did come loose. I tape it with aluminum tape. To secure it.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,970

    Ok. New flow switch. I have two vent pipe. One of the vent pipe that fix on the burner did come loose. I tape it with aluminum tape. To secure it.

    What is the pipe made of? PVC plastic? stainless steel? Metal tape is not a permanent fix.
    Flow switch and the other anti Condensation kit. If tapping on the part 17 gets that to move the way it is supposed to then you have narrowed it down.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • ArchimoreHorie
    ArchimoreHorie Member Posts: 23
    I will try that in the morning.
  • ArchimoreHorie
    ArchimoreHorie Member Posts: 23
    No more short cycle. But DHW is still on and off. Sometimes hot then. Cold