Radiators keep leaking - F&E system

Discussion in 'Plumbers' Talk' started by PenaltyCharge, Feb 14, 2020.

  1. PenaltyCharge

    PenaltyCharge New Member

    Hi guys,

    In the past 18 months I have had to replace 6 radiators (out of 12 in my house) due to pinhole leaks. The first 3 developed leaks on the ball by the lockshield end. On the last 3 the coating bubbled between half way up and near the top of the rads. The latest rad to go is a designer rad that I installed only a year ago! The others I believe were installed when the house was built (around 20 years ago).

    On most replacements I drained down the whole system so I could replace the old TRVs for new ones at the same time, each time I added inhibitor when filling the system again.
    On the last drain down I filled up with a cleaner for 5 days, drained down and filled up again with inhibitor.

    I thought I had loads of sludge because rads were only getting hot up the sides and top but I beleive my system isn't balanced properly because they all get uniformly very hot when I turn all the other rads off.

    Don't think it's related but for as long as I remember the HW & CH both have to be on the control panel for the rads to come on (I think it's the 3 port valve).

    My heating system has a light banging through the pipes when it's on, more when it first comes on then subdues after 30ish mins which started a couple of years ago.

    Last night I discovered this (see pic) in my airing cupboard and wondered if I'm on the brink of a disaster and if its connected?
    20200214_071523.jpg 20200214_071536.jpg 20200214_071552.jpg 20200214_071602.jpg

    I am not a professional plumber but competent enough to tackle most jobs.

    I just want to stop replacing rads!!
  2. dcox

    dcox Active Member

    That air separator in your pictures is clearly perforated so needs changing ASAP before you get a serious leak.

    Does the F&e tank pump over or get warm? If new water is constantly getting added to your system it will dilute any inhibitor so radiators will corrode from the inside out.
    Last edited: Feb 14, 2020
  3. dubsie

    dubsie Active Member

    As above could be any number of issues, air, diluted inhibitor due to pumping over or faulty valve, leaks etc etc.

    Position of the pump is a possibility as that will drag air in which cause serious corrosion.
    Last edited: Feb 14, 2020
  4. PenaltyCharge

    PenaltyCharge New Member

    The f&e tank does get hot water flowing into it from the expansion pipe, I have now lowered the pump setting to it's lowest. The plumber who fitted it a few years ago told me to just leave it on max.

    I bent the ball valve down sligtly so it doesn't keep filling with fresh water.
  5. The Teach

    The Teach Screwfix Select

    Which boiler do you have ?

    Others will always have different ideas how to sort the system out but from the info above:(


    Remove the air separator,reconfigure the openvent&cold feed to either a combined feed/vent or just a 22mm cold feed.

    Thoroughly flush all the central heating pipes,expansion tank and fit new radiators.

    locate and repair any water leaks & air being pulled into the system,

    Investigate wiring to get it working as per 3 port valve/programmer instructions.

    Flush the system hot,refill & run hot,basic balance.Check the water quality with a TDS meter.

    Add inhibitor & final balance the system with thermometers.

    Job done :D
  6. PenaltyCharge

    PenaltyCharge New Member

    It's an Ideal Classic if that helps?

    Do I have a type of air separator that is now obsolete? The ones available look very different.
  7. Jez Brown

    Jez Brown Member

    If you have still got sucking down and pumping over with the pump on low, you may have to raise the header. How high does the expansion pipe rise above the header tank ???
  8. Jimbo

    Jimbo Screwfix Select

    Likely there is a blockage at the point that the cold feed meets the boiler flow just near the pump.

    The corrosion is precisely because of the pumping over which has oxygenated the water. Without oxygen the corrosion by oxidisation cannot occur.

    I would suggest draining down, replacing the blocked section, replace the pump with a proportional pressure unit (eg ups 3), replace any remaining old radiators, replace the air separator with a spirovent and add a magna clean. then refill with a system cleaner. Circulate for a couple of weeks, and clean the magnaclean regularly during this time (to start with, after just an hour). Finally drain, flush and refill with x100.

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