Combi Boiler fault finding

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Combi Boiler fault finding

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  • #386142
    Neil Wyatt
    Moderator
      @neilwyatt

      Today our combi boiler has started blowing the internal fuses.

      They go almost straight away if it is in radiator + hot water mode, but in hot water mode I was able to run a bath before the fuse blew.

      I'm wondering if this is most likely to be the pump or something else?

      When I have daylight I will check the pump head and that the pump rotor isn't jammed, but any suggestions what else it could be (and how to test)?

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      #26349
      Neil Wyatt
      Moderator
        @neilwyatt
        #386144
        Alan Waddington 2
        Participant
          @alanwaddington2

          Need a bit more info, boiler make/model etc.

          However generally speaking blown fuses are usually down to pump, or water leaking into diverter head.

          #386146
          alan-lloyd
          Participant
            @alan-lloyd

            modern boilers are designed to fail safe to hot water only

            #386148
            Alan Waddington 2
            Participant
              @alanwaddington2

              Posted by alan lloyd 3 on 17/12/2018 19:18:26:

              modern boilers are designed to fail safe to hot water only

              Sorry Alan, but that’s not correct

              #386150
              blowlamp
              Participant
                @blowlamp

                If & when you end up needing a new boiler be sure to consider an Intergas

                I think there's only four moving parts inside. yes

                Martin.

                #386153
                Neil Wyatt
                Moderator
                  @neilwyatt
                  Posted by Alan Waddington 2 on 17/12/2018 19:12:30:

                  Need a bit more info, boiler make/model etc.

                  However generally speaking blown fuses are usually down to pump, or water leaking into diverter head.

                  It's a Main boiler I think a Combi 30 Eco condensing boiler (not 100% sure of the number)

                  I can't see any leaks. THe PCB doesn't show any signs of damage.

                  Irony is the pump is a Grundfoss UP XX 50 which everywhere says is one of the best!

                  #386154
                  bricky
                  Participant
                    @bricky

                    Check whether the condensate tube inside the boiler is not leaking and finding it's way into the electrics.This cost me a new boiler.

                    Frank

                    #386156
                    Alan Waddington 2
                    Participant
                      @alanwaddington2
                      Posted by Neil Wyatt on 17/12/2018 19:39:11:

                      Posted by Alan Waddington 2 on 17/12/2018 19:12:30:

                      Need a bit more info, boiler make/model etc.

                      However generally speaking blown fuses are usually down to pump, or water leaking into diverter head.

                      It's a Main boiler I think a Combi 30 Eco condensing boiler (not 100% sure of the number)

                      I can't see any leaks. THe PCB doesn't show any signs of damage.

                      Irony is the pump is a Grundfoss UP XX 50 which everywhere says is one of the best!

                      Take the diverter stepper motor head off, Black plastic thing with a 3 wire plug attached ( Pull out the metal clip and it will come off) look for signs of water ingress from the brass diverter body and stainless pin that the motor acts on…………if its dry, come back to me. If its wet you need a diverter rebuild kit and probably a new stepper motor.

                      #386157
                      Alan Waddington 2
                      Participant
                        @alanwaddington2
                        Posted by blowlamp on 17/12/2018 19:30:12:

                        If & when you end up needing a new boiler be sure to consider an Intergas

                        I think there's only four moving parts inside. yes

                        Martin.

                        On the money there Martin, my boiler of choice, fitted around 100 of them so far, great bit of kit.

                        #386165
                        Neil Wyatt
                        Moderator
                          @neilwyatt

                          Fired it up and I see steam coming from that 3-wire plug…

                          Looks like you are spot on!

                          diverter stepper.jpg

                          The stepper appears to work though, will it be OK to clean the contacts and dry it out?

                          Is the diverter rebuild within the realms of a DIY job? Will the system need draining down?

                          I see there's a sensor of some sort fitted to the bottom right that's weeping as well.

                          Not what I wanted a week before Christmas…

                          #386170
                          Pete White
                          Participant
                            @petewhite15172
                            Posted by Alan Waddington 2 on 17/12/2018 20:02:27:

                            Posted by blowlamp on 17/12/2018 19:30:12:

                            On the money there Martin, my boiler of choice, fitted around 100 of them so far, great bit of kit. am

                            I am saying nothing, only fitter two boiler and gased three Landrovers, still here to tell to tail, but sadly Mrs. does not ever trust me to work the thermostat these days.

                            But ………. MILs boiler, 94 year old, thats her not the boiler ??? bless her some would say, kept tripping the circuit breaker, traced by the gasman, no gaslady, to a leaking diverter valve, solenoid was replaced by the gasman a week earlier. Valve not checked properly…………thinks incompetent one.

                            #386171
                            Neil Wyatt
                            Moderator
                              @neilwyatt

                              I have found a motor and cartridge set.

                              I assume that I just have to:

                              Isolate mains and water.

                              Drain out using valve on right of boiler + hot taps.

                              Unscrew the valve cartridge from top of diverter.

                              Fit new cartridge + motor.

                              Close drain and refill

                              Good to go???

                              #386177
                              David George 1
                              Participant
                                @davidgeorge1

                                Hi Neil It is worth cleaning the pump rotor on the Grundfoss as well as the new spiral rotor collects debris and slows flow. I recently had to clean my pump. You just remove the four screws holding the pump to the housing unplug the cable and look at the spiral fins mine were full of bits of material. flow in the system was restored.

                                David

                                Edited By David George 1 on 17/12/2018 21:37:25

                                #386178
                                Alan Waddington 2
                                Participant
                                  @alanwaddington2
                                  Posted by Neil Wyatt on 17/12/2018 21:07:48:

                                  I have found a motor and cartridge set.

                                  I assume that I just have to:

                                  Isolate mains and water.

                                  Drain out using valve on right of boiler + hot taps.

                                  Unscrew the valve cartridge from top of diverter.

                                  Fit new cartridge + motor.

                                  Close drain and refill

                                  Good to go???

                                  Pretty much it…….Make a boiler engineer out of you yet Neil cheeky

                                  #386181
                                  Brian Sweeting 2
                                  Participant
                                    @briansweeting2

                                    Only thing that I would add is to start the job in the morning, then if you need something else the chances are the suppliers are still open.

                                    #386232
                                    Neil Wyatt
                                    Moderator
                                      @neilwyatt

                                      Thanks Alan, and others!

                                      Hopefully the bits will come tomorrow. Currently making the electricity meter spin at an unfeasible rate!

                                      #386244
                                      Phil Whitley
                                      Participant
                                        @philwhitley94135

                                        +1 for Intergas!!

                                        #386254
                                        Grindstone Cowboy
                                        Participant
                                          @grindstonecowboy

                                          + another 1 for Intergas as regards longevity and ease of repair if they do go wrong, although I was recently very impressed by the near-silence when running of the in-law's Vaillant Ecotec boiler – unaware of their reliability though.

                                           

                                          Edited to add:

                                          Adding a magnetic filter of some sort is well worth it, whatever the boiler.

                                          Edited By Rob Rimmer on 18/12/2018 13:19:47

                                          #386310
                                          Howard Lewis
                                          Participant
                                            @howardlewis46836

                                            Very interesting!

                                            Our 1973 cast iron boiler must be approaching end of life. (Its had a few thermocouples and the pump impellor has needed reshimming once or twice, so it's a bit like Trigger's broom!)

                                            Is it possible to buy something similar, still, without the complications of condensing, pressure tanks and the like?

                                            All advice gratefully received

                                            Howard

                                            fat fingers again!

                                            Edited By Howard Lewis on 18/12/2018 18:28:33

                                            #386314
                                            Alan Waddington 2
                                            Participant
                                              @alanwaddington2

                                              Posted by Howard Lewis on 18/12/2018 18:27:45:

                                              Very interesting!

                                              Our 1973 cast iron boiler must be approaching end of life. (Its had a few thermocouples and the pump impellor has needed reshimming once or twice, so it's a bit like Trigger's broom!)

                                              Is it possible to buy something similar, still, without the complications of condensing, pressure tanks and the like?

                                              All advice gratefully received

                                              Howard

                                              fat fingers again!

                                              Edited By Howard Lewis on 18/12/2018 18:28:33

                                              Sadly not Howard, all gas boilers must now be A rated energy efficient, which means condensing. The latest building reg's also require the fitting of smart controls, with either load compensation or a flue gas recovery system in place

                                              You can still run them on open vent, however i don't know why anyone would want to, it's a rubbish idea……Best thing to do with a 70's system is junk the lot and start from scratch. Benefits would include a much warmer house, and annual heating bills reduced by around 30%

                                              #386316
                                              martin perman 1
                                              Participant
                                                @martinperman1
                                                Posted by Alan Waddington 2 on 18/12/2018 18:38:04:

                                                Posted by Howard Lewis on 18/12/2018 18:27:45:

                                                Very interesting!

                                                Our 1973 cast iron boiler must be approaching end of life. (Its had a few thermocouples and the pump impellor has needed reshimming once or twice, so it's a bit like Trigger's broom!)

                                                Is it possible to buy something similar, still, without the complications of condensing, pressure tanks and the like?

                                                All advice gratefully received

                                                Howard

                                                fat fingers again!

                                                Edited By Howard Lewis on 18/12/2018 18:28:33

                                                Sadly not Howard, all gas boilers must now be A rated energy efficient, which means condensing. The latest building reg's also require the fitting of smart controls, with either load compensation or a flue gas recovery system in place

                                                You can still run them on open vent, however i don't know why anyone would want to, it's a rubbish idea……Best thing to do with a 70's system is junk the lot and start from scratch. Benefits would include a much warmer house, and annual heating bills reduced by around 30%

                                                I've managed to servive with a boiler and radiator valves and a pump why should I have stuff I've never needed.

                                                Martin P

                                                #386320
                                                Alan Waddington 2
                                                Participant
                                                  @alanwaddington2
                                                  Posted by martin perman on 18/12/2018 18:43:34:

                                                  I've managed to servive with a boiler and radiator valves and a pump why should I have stuff I've never needed.

                                                  Martin P

                                                  Yeah My Grandad managed perfectly well with a horse and cart until he got a truck……..cheeky

                                                  The truth is, since we signed up to the Kyoto agreement, the focus has been on energy efficiency, so the government decides what criteria needs to be met when a new boiler is fitted. Therefore you or i don't have a choice in the matter.

                                                  #386327
                                                  blowlamp
                                                  Participant
                                                    @blowlamp

                                                    I've got my Intergas installed along with weather compensation and an OpenTherm controller. I couldn't be happier with how it 'just works' throughout the seasons.

                                                    Come autumn, the system eases itself back on – barely noticeably at first, as radiators start to warm at very low levels, progressively increasing as the days & nights become cooler. The same happens in reverse as spring approaches.

                                                    It's very pleasing to be able to set the temperature and have the system maintain it despite changes in the weather. I'd definitely go with the same setup again if were were to move house or something.

                                                    Martin.

                                                    #386341
                                                    martin perman 1
                                                    Participant
                                                      @martinperman1

                                                      Thats sorted then I shall get my two open fire chimneys swept and use the coal fires again. what happens when an oap's boiler fails and he cant afford a new one with all the stuff he supposedly needs.

                                                      Martin P

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