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Baxi 100HE / heating system advice

Discussion in 'Plumbing and Central Heating' started by ChrisW79, 15 Sep 2012.

  1. ChrisW79

    ChrisW79

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    Location:
    Hampshire
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    United Kingdom
    Hi,

    I was hoping someone would be able to help me with a few queries:

    I have a Baxi 100HE heat only boiler, seperate OSO hot water tank, Zilmet expansion tank, pump etc. The pressure gauge on the expansion tank has recently stopped moving when the hot water is switched on. Previously, it would settle at 1.2bar cold then increase to about 1.8bar with the system at full tilt which you'd expect. Now, it just sits at 1.5bar maybe increasing to 1.6bar with the system running. The filling loop is disconnected.
    I'm assuming this would point to the bladder pressure in the expansion tank being zero or near zero but I thought I'd ask for another opinion, there is always a chance the gauge could be dud!
    If it does sound like the bladder needs to be press'd up again, would it be better to depressurise the system at the boiler drain on the H.Exch than use the relief valve on the expansion tank? I've heard the relief valves sometimes don't seat properly if they're used to drain down the system?

    The other thing concerns the boiler itself - I'm fully aware that the 100HE is a complete turkey but I've nursed the stupid thing along this far and it now works quite well. The main problem was with the ignition spark doing anything it could to escape actually jumping across the electrodes, preferring instead to jump to chassis / other wires / dust in the electronics box and so on...this was compounded by the slow spark rate of the 'old' style ignition PCB...leading to explosive ignition! There's now a new style green ign PCB which has a faster and I'd imagine stronger spark and the leads / electrodes have all been changed to the latest type. With the colder weather looming I'm still in two minds whether or not to change the boiler out, the main problem I have is that it is a top floor flat, so a change to another make would require a new vertical flue and all the associated costs (mainly the need for a scaffold to install it!).
    I contacted Baxi and was told that I could re-use the existing flue with their Solo HE boiler as it retains the same H.Exch / internal layout as the 100HE. Can anyone tell me if this boiler is likely to be as hopeless as the 100HE? I have a brand new H.Exch in the loft for the current one as it's starting to corrode so shall I just have this swapped or is the Solo HE improved enough to justify a complete swap?

    Many thanks in advance for any help,

    Chris.
     
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  3. gaspro1981

    gaspro1981

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    Chris are you an rgi ??
     
  4. ChrisW79

    ChrisW79

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    I'm not an RGI myself, any previous work on anything to do with the H.Exch / burner and all associated gas parts has been carried out by a registered professional. The only thing I've ever done is repair or swap out the PCB's (I'm a registered EngTech myself) I wouldn't attempt anything else!
     
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