Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

WM series 2 Ultra 155 b-25 error code

stephen11962 Member Posts: 40
edited May 2016 in Gas Heating
Ultra 155, TekMar controls, 8 years in service, b 25 error code, outlet temp rise too fast:
Boiler pump, Taco 0014-F1, has 125v at junction box but I cannot tell if water is circulating. Everything else seems OK. Could the boiler pump cartridge be bad?


  • njtommy
    njtommy Member Posts: 1,105
    Yes if pump is not running you will get that fault. I would make sure the pump is running first.
  • stephen11962
    stephen11962 Member Posts: 40
    I am at a loss about determining if the pump is running. I did slowly close down one of the ball valves isolating the pump and heard what seems to be a restriction of flow of the water.

    The boiler sends out (seeming) protests of expansion noises when firing, starting about a month ago. This noise was the thing that got me paying attention to boiler and once while trying to locate the exact source of the noise I saw the error code, which I have now seen seen several times. I followed the trouble shooting steps in the manual, including air in the system, etc.

    So, now I seem to have determined that some water is circulating, but enough?? Is is possible for the pump to be working but not at enough capacity?
  • SWEI
    SWEI Member Posts: 7,356
    Put a torch on the pipe near the pump inlet and see how long it takes for the pipe to cool down after you remove the heat.
  • njtommy
    njtommy Member Posts: 1,105
    Are you amble to check the voltage or amp draw at the pump?
  • stephen11962
    stephen11962 Member Posts: 40
    Voltage yes, amperage no - not sure how to do. Have the meter thought.
  • njtommy
    njtommy Member Posts: 1,105
    I would check to see if the motor is very hot to the touch and check voltage to it. Also if the boiler is off for a while does the supply and return water temps seems to be close in temp?
  • stephen11962
    stephen11962 Member Posts: 40
    Prior to posting here, I called WM to try to talk to someone. They were busy then and finally called back a little while ago:

    They indicated that the Taco circulating pump was probably the problem if every thing else seemed to be normal. So, I ordered a replacement cartridge on line. Three supply houses in my area do not stock this item (Taco 0014-004RP) so I have to wait for the UPS man. WM said that the wait should not be a problem since the b-25 error code indicates that the boiler is "protecting itself" by shutting down and would reset itself in 10 minutes.

    I'll report the results. Thanks for all suggestions.

  • SWEI
    SWEI Member Posts: 7,356
    A 0014 is a lot of pump. You might be able to get by with something smaller, which would cost less both to buy and to operate.
  • kcopp
    kcopp Member Posts: 4,188
    edited May 2016
    Grundfos 26-99 would work... speed 2/ medium
  • 4Johnpipe
    4Johnpipe Member Posts: 479
    How's the heat exchanger? Clogged heat ex will mimick bad pump.
    Considerate People, Considerate Service, Consider It Done!
    email: [email protected]
  • unclejohn
    unclejohn Member Posts: 1,830
    Whats the delta T at the boiler. does and rads or baseboard heat.
  • stephen11962
    stephen11962 Member Posts: 40
    Back again...
    -Pump size is pretty much fixed - unless that can be changed without removing the whole pump assembly. Change out the cartridge is 4 bolts and some water on the floor.

    -Heat exchanger? Boiler powers radiant heat in concrete slab (3,000sf), hot water storage and FTR on second floor.

    -Delta T? Do not have thermometer for that

  • lchmb
    lchmb Member Posts: 2,997
    has the system been serviced?
  • stephen11962
    stephen11962 Member Posts: 40
    Back once again. Responding to comments above:
    Boiler pump sized by WM, came with boiler.
    Pump is often very hot, water circulating in loop can reach 180 degrees and whole pump assembly is in intimate contact with piping.
    Radiant heat works, but is low temp and does not trigger error, b-25, too fast rise in outlet temp.
    The new cartridge did not make a difference. Lost $$$.
    Talked to WM again. Said to check outlet water temp sensor. Bought new one at $13. Installed. First observation, everything seems to be OK, but I am skeptical. Too easy a fix. Have to wait for several more cycles.
    Boiler still makes loud clicking noises (new the last 2 months, with error code?) that come from the boiler itself. Putting the boiler cover on significantly muffles the noise. Tried locating source by touching various parts with metal rod (too hot to touch). No luck. Frustrating job. Have to wait indeterminate time for the next noise.
  • Tom_133
    Tom_133 Member Posts: 848
    Sorry stephen, without tooling like a amp probe, and an ohm meter it's hard to nail down pump or sensor. That code is either supply or return sensor, bad pump, or bad control, typically. It can probably show up with a host of other ones, but those are the trouble makers.

    Montpelier Vt
  • KCA_2
    KCA_2 Member Posts: 308
    Interesting! I know someone here by me that has a very similar issue.... :-))
    :-) Ken