Re-fitting olds rads!

Discussion in 'Plumbers' Talk' started by thestraycat, Sep 30, 2020.

  1. thestraycat

    thestraycat Member

    Hey guys,

    Nice easy one here. I'm currently removing the radiators in my house one by one to decorated the rooms fully. I'm then upcycling the radiators, with new primer and paint and refitting the existing ones back again.

    My question is, should i be using PTFE tape on the male part of the radiator tails even if originally there was none fitted?

    Also, is it DIY friendly for me to change my double lock shield style radiators to TRV style prior to putting them back on? Seems like the best time was all?

    Opinions and advice appreciated. Cheers guys!
  2. andy48

    andy48 Screwfix Select

    1. If you are changing the valves, the new ones will come with new tails. These will require PTFE on the threads which screw into the radiators.
    2. If you are keeping the old valves you will still need PTFE on those threads. They may originally have been put into the radiators with hemp and some form of plumbing putty. If so then:
    2a. It would be best, if possible, to clean out the radiator threads first.
    2b. If not possible, probably need less PTFE.
    3. Using ordinary PTFE (not gas PTFE, which is much thicker), use about 12 wraps to start with. Screw tail into radiator. If it goes in tight, probably enough. If loose, remove PTFE, try again with 15 wraps and so on.
    4. Holding tail with the threads towards you, wrap PTFE on clockwise, i.e. so that screwing it in doesn't strip the PTFE off.
    5. Very sensible time to add TRVs, and renew the lock shield valve on the other end of each radiator at the same time.
    6. TRV should go on the flow side, which is the side which gets hottest most quickly from cold. However, most decent TRVs these days are bi-directional, so this doesn't matter.
    7. As TRVs act on room air temperature they are best placed with the best exposure to air, so not in a corner. With decent TRVs I'd suggest this takes priority over 6. above.
    8. The room with the room thermostat in it should not have a TRV, as they will "fight" each other. However, if it does have a TRV, turn it up to maximum, so that the temperature is controlled by the room thermostat.
    WillyEckerslike likes this.
  3. Dave does Gas

    Dave does Gas Screwfix Select

    Top Tip when you remove the brackets, to plaster? decorate put some long screws into the original holes to keep them marked. Nothing harder than trying to get a rad back in the exact spot.
    Mike83 and Astramax like this.
  4. thestraycat

    thestraycat Member

    @andy48 - Thanks for that detailed break down! Appreciate you helping me out, as a DIY'er this sort of information is invaluable.
    @Dave does Gas - Yes! I normally go one better, take pictures of the brackets left on the wall, label them when there off and leave the screws in so i don't plaster over! Top tips indeed!

    All great information guys! thanks a lot!

    A few other quickies, my pipes in some rooms dont come straight up from the floor boards vertically into the rads. Some have been bent to reach etc. I was planning on just fitting some radsnaps or radcovers to the pipes that come up straight, but does anyone know of any pipe cover product than can deal with curves? I know there a tiny bit of give in the straight covers but not enough to deal with my 90 degree curves.

    Are there any particular brand of TRV that i should be looking out for... Happy to spend if their worth it....Also are the TRV replacements standardized sizes to match my current lock shields sizes? I theory i shouldn't need to adjust or move the existing pipe work etc.

    Lastly, whilst i have the opportunity of having these rads off, is there anything else i should look at doing prior to putting them back on? (DIY friendly of course...)
  5. WillyEckerslike

    WillyEckerslike Screwfix Select

    Radsnaps don't accommodate bends/curves very well in my experience. I'm all ears if they do and I've been missing a trick.
  6. Joe the Plumber

    Joe the Plumber Screwfix Select

    The only curvy radsnaps I've come across are made by Dulux and Crown (amongst others) and you apply them with a brush (ie, paint!)

    Do have a good look at your old radiators. If there's much rust on the bottom or the back (and a single rust spot may be hiding a pinhole),
    I'd think about replacing them.

    Our sponsors will give you nice, new Drayton TRVs and lockshield valves included in the price of each rad at present too.
    WillyEckerslike likes this.
  7. DIYDave.

    DIYDave. Screwfix Select

    I’m with you on labelling the rad brackets so they go back easily in exactly the same place - good tip from DDG

    I mark mine with a L & R and also mark the screw positions so again, end up at exact same height

    Some brackets have a combination of screw holes and slots and usually you can see where the screws has been removed as leaves a mark/dent on the bracket

    I’ve also removed brackets where positioning them correctly was obviously a previous problem as several marks left from changing screw position

    Sharpie pen (or similar) leaves a clear mark and saves time when refitting

    Rads can collect a fair bit of dust and as your prepping them prior to painting, again more dust

    Take them into garden (if practical) and give a good wash down all over to remove all dust and grime prior to painting - especially the fins that collect dust

    Whislt rads are in the garden, good idea to blast them through with the hose to remove build up of gunk and sludge. Get the water flowing through the rad, agitate the rad depending on size, stand on each end and blast again to remove as much sludge as possible. Don’t do this over your patio as the black sludge can really stain

    One last tip for you /
    Once rads drained and removed from wall, flip them over and carry them out of the house upside down

    Saves any sludge dripping out over floors

    Enjoy the process and paint the pipes - if less than straight, no other option
  8. thestraycat

    thestraycat Member

    @WillyEckerslike - I know right... Surprised no ones really bought anything into the market. I get that the proper process should be sand, prime, paint .... but on occasion (from a DIY'ers perspective) A cheap curvy radsnap product to finish off a newly painted radiator with less than perfect straight pipes would fit the bill tbh.

    @Joe the Plumber - Yeah, i've given each a thorough clean and inspection prior to preparing them for upcycling. I'll look into the sponsors rad options.. But due to being out of work atm, this was really an attempt at modernizing and smartening up the existing rads as there in reasonably good nic if i could have got TRV's on easily and cheaply i'd be over the moon.

    @Diydave - My process is exactly as you've described so i'm glad i'm not making a hash of it. I currently have a few pots outside for holding the rad off the floor for sanding, i usually take it over to the drain, stand it up on 2 bits of wood and stick a hose in the other end and watch the sludge come out, very satisfying! How do you agitate them exactly? I havn't been doing that to be honest... I usually blast each 4 times, from the left side and then flip is over and do the left side again and then the same process for the right.. I often find than after flushing through and flipping it i get another blast of sludge for my efforts so have stuck with it. And yes, the tip about flipping them has been a godsend.

    If i were to get new TRV's put on say 8 rads... how long would that take and what would be a fair price for a plumber to do it for me if need be?
    Joe the Plumber likes this.
  9. DIYDave.

    DIYDave. Screwfix Select

    Looks like you’ve got the flushing process all sorted and by ‘agitating’, your doing it already !

    As you know, the sludge sits and compacts in bottom of rad, if you just keep rad horizontal and flush through, then you’re gonna remove less muck

    By flipping rad up/down/ end to end/, and flushing through, your encouraging more crud to work loose and be flushed out

    I’ve heard about tapping base of rad with a rubber mallet to also help loosen muck but no idea if this really helps or not ?
  10. Mike83

    Mike83 Screwfix Select

    I usually do this but occasionally I measure the height of the brackets from the skirting board.
    I note this down on the radiator with tape

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