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Need help with Bosch zwb42-3a combi boiler code

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Hey so I have a bosch zwb42-3a combi boiler that also does my DHW and had it installed about 5 years ago with no problems but over the weekend I got a code A7 and when I look it up it says it’s a temp sensor and would like to replace it myself but having a hard time finding the right on when I look it up in the book…also I never had any service done to it and having a hard time trying to find anyone in my area that even works in them.. is this something I can do I’m very good with tools and I’m also an electrician but not trying to pay an arm and a leg to swap out a sensor 

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  • JUGHNE
    JUGHNE Member Posts: 11,074
    edited February 2023
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    5 years with no service, what does the book say for regular maintenance?

    You can probably do it yourself as needed. I know electricians (being one myself) are capable. ;)
    Foxrider714
  • Foxrider714
    Foxrider714 Member Posts: 3
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    When I talked to Bosch they even told me should not need anything for about every 5 years.. sucks I called some shops on there site and they tell me they don’t work on them 🤷‍♂️.. so I’m just going to change it but I wanna make sure I get the right sensor and change the correct one 
  • JUGHNE
    JUGHNE Member Posts: 11,074
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    Book should give you correct ohm/temp readings.

    You could check them all and find the one out of spec.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,607
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    @Foxrider714

    Who installed it? They should be able to work on it
  • Foxrider714
    Foxrider714 Member Posts: 3
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    Ya I have to find it or look it up online.. like I said shows a code for A7 and when I looked it up it says DHW temp sensor.. so should only be one I just have to find the part number
  • fenkel
    fenkel Member Posts: 162
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    check the wiring first for shorts..
    part number is 87145001170
  • Big Ed_4
    Big Ed_4 Member Posts: 2,805
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    It is not very hard , drop and drain hot water pressure .Leaving the hot water drain open. Lift up the spring clip until it stops which holds the sensor in place , You will have to twist and pull out ,install the new sensor using a little silicone grease on the new o-ring to insert it fully .

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