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DHW heat exchanger Worcester bosch 37 CDI - please help!:(

Discussion in 'Plumbing and Central Heating' started by pjriest, 2 Sep 2013.

  1. pjriest

    pjriest

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    Hi all. For a while now our boiler has been overheating and turning off (water goes cold) and then comes back on. Very annoying. Wifes gone mad.

    Technician has confirmed that the DHW is dirty and needs replacing. I've bought a new one but he cant change it, saying that he needs space to move the heat exchanger 'back' (towards the wall) to take it out, but there is only about a 3mm gap between it and a pipe running there. He said that since the HE could not be moved back, he would have to drain the whole system in order to take loads of the boiler parts out first.

    Now this confused me. Less than a year ago I'd had the HE replaced (apparently with a new one by WB but i suspect i was short changed as it's already gone). The entire system had not been drained then as far as I recall.

    So I checked the service manual as the quoted price concerned me. the procedure appears to be quite simple. It says that the 'hydraulic block' should be removed first. Given what i've seen from the inside of the boiler, I can only assume that this means something that's in *front* of the HE (there is nothing behind it!!). If that is the case, surely it comes out by moving toward the front of the boiler and NOT backward as suggested by the technician.

    Im sure someone out there can just tell me: Standing in front of the boiler, does the DHW move backward to be dismantled, or forward, toward you. Should I just go with what my technician says and pay him hundreds to replace the H.E? He does not seem like an expert with WB boilers though is obviously gas safe registered.

    Thanks.
    -PJ
     
  2. john90

    john90

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    usually I take out the plate from the back (towards the wall) - can be straightforward but can be a right pain if space is restricted
     
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  4. pjriest

    pjriest

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    The thing is almost touching a pipe (that runs horizontally across the whole H.E). I guess that's a preferred method then.. but am i right about the formal instructions in the service manual? they appear to say that the thing in front should be taken off in which case it would pop out.
     
  5. pjriest

    pjriest

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    From the manual:

    29. DHW Heat exchanger
    
    Remove the Hydraulic block from the boiler (See Removing the Hydraulic Block).

    29.1 Undo the two screws (B) securing the plastic housings to the heat exchanger.

    29.2 Remove the heat exchanger.
    
    To refit, follow the above in reverse. Ensure any seals that have been disturbed are renewed
     
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