Thermostatic radiator valve advice.

Discussion in 'Plumbers' Talk' started by Michael Doherty, Mar 2, 2015.

  1. Michael Doherty

    Michael Doherty New Member

    Hi All
    I am trying to solve a few problems with our Heating system that was installed last year by the previous owner and wonder if some of the problems we have is due to bad workmanship.
    A few of the radiators have the Thermostatic Valve on the bottom of the radiator and I have been told that they should be on the Top.Also on a couple of radiators the IN and OUT are on the same side (Top and Bottom)These are 1.500mm radiators.Again I have been told that the in and out should be on opposite sides for larger Radiators.
    Could this set up cause bad flow and cold bottoms we are having with some radiators on the system.

    Thanks for any advice
    Mick
     
  2. Hi Michael.

    'Old' systems which worked on gravity, or even 'one-pipe' systems, tended to have the rad valves fitted on diagonally-opposite ends of the rads. This was because it relied for its actual circulation on the water cooling and sinking to the bottom, and hot water rising to the highest point - that gave it its 'flow'. Rads from these days had the same connectors in all 4 corners, and peeps had to blank out the 2 they didn't need to use depending on the type of circuit they were going to be used on.

    More modern pump-driven, 2-pipe systems don't require this, and modern rads also tend to have just 2 connectors - both at the bottom (and a bleed screw at the top).

    So, what system do you have?!

    I presume it does have a pump. But is it a one-pipe or 2-pipe system?

    Look underneath your rads - do the 2 pipes disappear into the floor separately, or are they also joined together by a connecting pipe?

    I'm not sure what the situation is with having both connectors on the same side, top and bottom, but it doesn't sound ideal at first glance (mixed metawhats...). I do remember, tho', the time when rads came with rubber bungs inside them that needed pushing out - or not - depending on the kind of system it was to be installed to, so possibly it's that kind of setup?

    But I don't know.

    First thing, tho' - what type of system do you have?
     
  3. sam spade

    sam spade Active Member

    It doesn't matter. The important thing is that the flow through the TRV goes in the correct direction. Look for arrows on the metal body of the valve. If two arrows, the flow can go in either direction, If one arrow (rare nowadays), the water must flow in the direction of the arrow - towards rad on the hotter pipe, away from rad on cooler pipe.

    This also does not matter. In fact, the British Standard (BS EN 442) for testing radiators specifies same end connection as, in theory, it produces the maximum output - by 2%!

    If it was a completely new system, including pipes, it's very unlikely to be a single pipe system.
     
  4. Michael Doherty

    Michael Doherty New Member

    Hi Devils Advocate
    Its a 2 pipe System.All the pipes Disappear into the wall separately.The system installed is a modern one all new radiators and pipe work.
    We live in a very old large house so the previous owner put a new central heating system in by himself with help from a friend in the business.I suspect that corners may have been cut to save money as the house was up for sale during the Heating work.
    The Radiators at the far end of the house only warm up a bit.I suspect the pump he put in is not up for the job.Some of the Radiators that we are having problems with are fitted as I mentioned in my post.This is why I hope its just a simply fix and can sort it out myself.....with some good advice :)
     
  5. It might be as simple as the system not having been balanced - do any rads get hot? If so, which ones.

    How quickly do the 'hot' ones heat up from cold?

    Make and model of boiler, and how many rads/rooms?
     
  6. Dave does Gas

    Dave does Gas Screwfix Select

    Probably as DA says you may well need to ballance the system. If your lucky its a simple job but quite often it a bit laborious. Have a search on here its been covered in detail in the past and should help you out without you having to spend any hard earned money.
     
  7. Michael Doherty

    Michael Doherty New Member

    To be honest I thought I had Balanced the system but now I am having 2nd thoughts to weather I did it correctly.I started from the nearest the boiler and adjusted to the far side of the house (being opened fully)
    Should I have adjusted top to bottom of the house or end to end ??
    We have 3 floors to heat up.
    Also I don't think I turned off the Boiler when I balanced the system.....could this also be a problem ?
    We have a total of 16 radiators working on the System and the ones close to the boiler (on 3 floors)get piping hot.Its the ones at the opposite end of the House that stay warm.
    I will spend the afternoon balancing the system.....thanks for all your help DA, Dave and Sam
     
  8. sam spade

    sam spade Active Member

    It would be an even bigger problem if the boiler was off!

    How are you balancing the system?
     
  9. Hi Michael - (puts on deerstalker, lights pipe in mouth, slowly strokes chin betwixt thumb and forefinger...) - so the rads nearest the boiler get piping hot, and the ones further away only warm?

    Hmmm... :rolleyes:
     
  10. Michael Doherty

    Michael Doherty New Member

    @sam,I thought you need to turn off the Pump and Boiler when Balancing the Radiators.Maybe I misunderstood from Bleeding the Radiators.Watched a couple of good videos on here so should be ok now.

    So Sherlock :)...I tried balancing the system last night and got the cooler Radiators quite hot (Not roasting) so today I will tweek the once on a quarter of a turn as they are not so hot now.
    Because its a Big house on 3 floors and the far radiators are the cooler ones do you think the pump could not be up to the Job?
    Its a Dab pump (Class F,Energy C....if that meens anything to you) No 3 max 0.34.When the pump is on Max setting for a while it starts to vibrate the pipes and needs to be turned down to no 1setting.
    Boiler is a Devil Termique .
    I did notice last week that when we turned the Pump on max the far radiators seemed to get hotter although still cold at bottom but had to tunn down to min setting after vibrating and waking my kids up in the night :(

    I will stick with the Balancing but any ideas if pump needs up-grading and is the cause of the problem.
     
  11. sam spade

    sam spade Active Member

    It would be helpful if you described your balancing procedure.
     
  12. Michael Doherty

    Michael Doherty New Member

    Sam...so last night with the Heating and pump on I turned off all the Radiators that were working well(Most of these were on top floors)The Radiators that were not working so well did warm up better but would not say they were Boiling hot.Then I turned all the radiators (before working well)back on a Quarter of a turn.This morning these radiators were not so hot so I have now given them another Half a turn on.
    So To recap .....all the radiators that were luke warm and cold at the bottom are open full and the radiators that have always been working are at the moment Half a turn open from the Closed position.
    All of this has been done with the Thermostatic Valve turned to max on ALL radiators (not 100% sure if this is correct)
    I have watched a couple of Youtube vid's on balancing and think I have done it correct......what do you think.
     
  13. Dave does Gas

    Dave does Gas Screwfix Select

    Whats the output of the boiler and what size pipes coming off it to the pump
    Incidently is that a French boiler and are you in France, If so can you give us a few photos of the pump and zone valve area and a general idea of the layout of the system
     
  14. BLUEJACKET

    BLUEJACKET Active Member

    Generally on 1 leg, with both arms out if that helps...
     
    plumber-boy likes this.
  15. Dave does Gas

    Dave does Gas Screwfix Select

    :D:D:D
     
  16. Michael Doherty

    Michael Doherty New Member

    So .....yes you are correct Dave we are in France although the System was fitted by a British Plumber and British owner.I understand that most of the material come from the UK so it's not a French system if there is such a thing
    The size of the pipes coming out of the pump are appox 22mm and going into the radiators are 15mm though-out the house.I will try and find out the output of the boiler.
    Here are lots of picture if it helps and also a couple of pictures of the plumbing of the radiators that did not look right to me when I started this post and thought it could just be the fitting of the radiators..... no idea of the layout of the system but willing to find out if it's important and up-load more pictures.
    Cheers guys for trying to help me with this ;)
     

    Attached Files:

  17. sam spade

    sam spade Active Member

    You have the right idea, but you are making much too big changes. Try this method:

    1. Remove all TRV heads and set all wheel valves to fully open.
    2. Set all lockshield valves to 1/3 of a turn open from closed (fully clockwise).
    3. Start boiler and allow system to warm up
    4. If necessary adjust pump speed to increase/decrease the temp difference at the boiler. (See boiler manual.)
    5. Feel all return pipes (cooler one) to see how warm they are.
    6. If they all appear to be the same temperature and there is a noticeable difference between flow and return, go to END
    7. Open the LS valve on the coolest return pipe by 1/12th turn or less. (this may be a different rad each time)
    8. Wait 5 minutes
    9. Repeat from 4
    END

    Do no expect perfection. The adjustment each time is very small and you need to leave time (say 5-10 mins) between each cycle for the system to settle down.

    When finished replace all TRV heads and set to required temperature. Set all wheel valves to required position.
     
  18. Michael Doherty

    Michael Doherty New Member

    Ok ....thanks Sam I'll give it a go.
     

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