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Discuss Replacement radiators with/without replacement pipework?k in the Central Heating Forum area at

  1. damovs

    damovs New Member

    I live in a small 2-bed bungalow, with a relatively new Worcester Greenstar 30Si Compact combi boiler running 7 radiators. The radiators and micro-bore pipework are about 18 years old, having been installed just prior to me moving in and with a previous boiler. Current boiler is 2.5 years old.
    Since the new boiler was installed, it doesn't seem to have been working as well as the replacement, (by that I mean the house felt cold), and I did get a Worcester engineer out after about a year and was told it was a 'circulation problem' and nothing to do with boiler. So I had a power flush/clean done by my plumber, but was also advised that the boiler was too powerful for the number/size of rads, and they would benefit from replacement. It was also recommended that I upgrade pipework. Plus, I know this winter was cold, but my gas consumption was up 25% on prev year, and that is on the back of a new and supposedly more efficient boiler.

    So after that preamble, I would like advice on whether there is any benefit in replacing the radiators without replacing the pipework too, and upgrading to 15mm pipe? The reason I ask is only because of the disruption it will cause, from point of view of redecorating required after upgrading to 15mm pipe. I definitely think that all the rads could do with replacing with larger ones, but then would micro-bore be up to the job? Or even new microbore rather than 15mm, as that would still be easier? (Although all the existing pipework comes down from loft rather than running under floor, and is boxed in, extra size to box in 15mm pipe for bathroom would prevent door closing.)

    Apols if this is covered elsewhere on forum. I did search but found nothing to answer my question.

    Thanks for all advice.
  2. scott_d

    scott_d Plumber GSR Top Contributor!!

    Microbore should cope as long as it's not a badly designed system or sludged up.

    You could try replacing one radiator and seeing if it's an improvement?

    Loft insulation will help bring heating costs down and also a good programmer and thermostat and thermostatic radiator valves
  3. damovs

    damovs New Member

    Thanks for the quick reply and advice Scott.
    I should have said that I also added extra insulation to loft after boiler installed, as I assumed this must be the reason why the house felt cold. So all good there I think.
    And there is remote digistat fitted with boiler.

    I must also add that the rads do get hot, it's not that they don't, but in the winter the house didn't feel warm, which is why I am all for an increase in rad size. I just didn't know if that is a false economy without replacing the pipework at the same time.
  4. Rob Foster

    Rob Foster Top Contributor!!

    do a heat piccy of the gaff when it gets colder or at night to see where the warm stuff is going use an app for this
  5. scott_d

    scott_d Plumber GSR Top Contributor!!

    If the rads get hot it suggests the pipework is ok

    So either the rads are too small or you now have better control of the heating and it's shutting off when the house is up to temp and you feel it's colder than it use to be.

    Where is your thermostat and what do you set it to?
  6. damovs

    damovs New Member

    The room stat is in a bedroom, near doorway and away from radiator & window. During the winter I may have it set to about 21c, but there have been times (on coldest days) when it practically took all day to reach it, maybe starting at 15/16c when it was off all night. Needless to say it has been dormant these past few months, but thought I should try and resolve problem before cold arrives again.
    But I think I will take your advice and initially replace 3 rads for larger ones, in 2 bedrooms & lounge, and see how that goes. (Not myself, but get someone who knows how! I have done it in the past, but with caused a leak when reconnecting! And I guess they will have to be exactly the same width as pipework already in place.)

    And thanks Rob, I will look into a heat pic of house, tho earlier in the year when we had snow it wasn't thawing on the roof so I took that to be a good sign.

    Thanks for the advice.
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