Announcement

Collapse
No announcement yet.

Worcester Heatslave 12/14 oil combi locking out after 4 1/2 mins

Collapse
  • If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Worcester Heatslave 12/14 oil combi locking out after 4 1/2 mins

    Combi is 12 years old. Installed it myself and no real problems. New pump and nozzle fitted 5 years ago. Good knowledge of electronics, electrical and mechanical. Have DMM and some test-kit.
    All going well until last week - Boiler ignites and flame appears, but lock-out triggers after about 4 1/2 mins approx. Can be reset and burner fires again, but lock-out occurs again after about 4 1/2 mins. Can keep re-starting but lock-out keeps occuring after roughly same time delay.
    Have already bled the oil pump bleed-valve, no air present and oil emerges. Flame on burner appears good. Photo cell appreas to detect when flame is extinguisinig if I bleed oil as it briefly loses pressure and flame goes out deliberately. The system then energises the transformer and spark-circuit to re-ignite the flame automatically. All seems to behave okay, but still locking-out after about 4 1/2 mins.
    Yesterday, I bought a new Honeywell Burner Control Unit tf 832.2 (30) but the same problem exists.
    Both water heater thermostat, cross-over valve and heating thermostat appear to still control temp and everything. The flow control valve still works.
    Any more suggestions since I am now at a loss.
    Help???
    PaulB

  • #2
    FYI - the boiler continued to lock-out, however checking the fuel solenoid valve, (Danfoss 071N0051) I noted this was getting hot on one side. It has been working but I suspect intermittently (once it gets warm). The solenoid coil has now however gone open-loop and the oil is not being delivered to the jet anymore. Have ordered new solenoid coil and will update once fitted. I originally checked the resistance of the coil at the beginning when the fault first appeared, but the coil would have been cold!
    Suspect the coil has been partially connected but once it warms up - thermal expansion has caused it to go O/L and shut off the oil. Only a theory, but have disassembled the whole control circuits, relays, checked every solder joint and wire - no other faults found (so far).
    To be continued..........
    Paul

    Comment


    • #3
      Problem solved.
      The solenoid coil controling the fuel from the pump to the burner was intermittent. When cold it showed a resistance but once used for a few minutes and it warmed-up, the coil went open-loop and shut off the oil - hence the lock-out.
      As temporary measure whilst awaiting a new coil, have used a v. similar coil from an old washing-machine that has exactlly the same resistance and 240VAC and almost the same size. It has been working okay for several days. New part arrived now and all okay.
      Lesson leant - resistances may look okay when everything is cold - but thermal expansion can change a part's status.
      Paul

      Comment


      • #4
        PaulB you are a superstar. Also, isn't the internet brilliant. Oh, and this website is great.
        PaulB, I had similar symptoms with my 12/14, and your thread pointed me straight to the solenoid. I had a spare solenoid on an old boiler I had kept at the bottom of the garden for exactly this Fitted in 5 minutes and so far its working fine.

        Comment


        • #5
          Originally posted by PaulB View Post
          Problem solved.
          The solenoid coil controling the fuel from the pump to the burner was intermittent. When cold it showed a resistance but once used for a few minutes and it warmed-up, the coil went open-loop and shut off the oil - hence the lock-out.
          As temporary measure whilst awaiting a new coil, have used a v. similar coil from an old washing-machine that has exactlly the same resistance and 240VAC and almost the same size. It has been working okay for several days. New part arrived now and all okay.
          Lesson leant - resistances may look okay when everything is cold - but thermal expansion can change a part's status.
          Paul
          Hello all,

          New to this site but having a similar problem with our heatslave 18/25 just wondering if it could be the same cause? Have had a engineer out and he changed the control unit which has helped for about 2 weeks but the boiler has started to do it again. The symptoms seem the same boiler works fine when cold or you use the reset button under the front panel but will shut down after the burner has fired maybe once or twice.

          Comment


          • #6
            Same problem

            10 year old Worcester Heatslave 12/14. Symptoms: would only burn for around 12 minutes before locking out, whether providing hot water or central heating. (Therefore tended to lockout after coming on in the morning.) Simple to check the Oil Pump Coil with a multimeter - isolate boiler and remove connector from the coil check across the two adjacent conductors. When cold gives approx.2.5KOhms, immediately after lockout it is open circuit. Simple matter to replace coil (approx. 20) only tool required - appropriate size allen key.
            Many thanks to PaulB and to Boilerguide. Long may you maintain these forum posts for the benefit of those of us prepared to have a go at fault finding ourselves.

            Comment


            • #7
              Just wanted to sign up to say thanks to the advice/outcome in this thread, my boiler is now working again!!
              Being without heating over Christmas was no fun and i resorted to fixing it myself because it was really hard to get someone to come out!

              Comment


              • #8
                Replacement Coil?

                Hi Stuart - where can i get an Oil Pump Coil?
                My symptoms are exactly the same as this
                Cheers. Adz




                Originally posted by StuartN View Post
                10 year old Worcester Heatslave 12/14. Symptoms: would only burn for around 12 minutes before locking out, whether providing hot water or central heating. (Therefore tended to lockout after coming on in the morning.) Simple to check the Oil Pump Coil with a multimeter - isolate boiler and remove connector from the coil check across the two adjacent conductors. When cold gives approx.2.5KOhms, immediately after lockout it is open circuit. Simple matter to replace coil (approx. 20) only tool required - appropriate size allen key.
                Many thanks to PaulB and to Boilerguide. Long may you maintain these forum posts for the benefit of those of us prepared to have a go at fault finding ourselves.

                Comment


                • #9
                  Just a quick update - most grateful to the help provided by this Forum, through StuartN and PaulB. The Danfoss 071N0010 pump coil was replaced and now working perfectly. Thanks again. Adz

                  Comment

                  Working...
                  X