Cooling radiators as heating warms up and it's not the TRV's

Discussion in 'Plumbers' Talk' started by Christian8888hyde, Jan 25, 2015.

  1. Christian8888hyde

    Christian8888hyde New Member

    I have a worcester greenstar 28 boiler. I live in a moderate sized semi. I have recently replaced two undersized radiators in our two main bedrooms with some bigger column rads!! Very nice too!
    The problem is when the boiler fire up in the morning within twenty min the upstairs bedroom radiators are hot and all the rest in the house. As the temperature rises to near its setpoint after say one hour the radars in the bedrooms begin to cool, as if the TRVS were kicking in, but they aren't there fully open! If you feel the pipes the feed is hottish for a while but the return I'd stone cold! I've but a stethoscope on the two valves and nothing can be herd! The upstairs bathroom radiator is bouncing and the little bedroom does as it's told!! I've tried balancing the system and this does increase the warm up time, but the underlying cooling down problem still exists.
    The pumps on full iii 3
    I had a couple of ideas but I'm being to disappear up my own backside

    Thought sludge might have gone into the system from the old radiators and blocked the pipes?? Not convinced!!
    Thought he pump may slow down when the temp gets closer to the setpoint??? That's **** is it does!!
    I've got all the gear, but am running out of ideas??
    Come on fire a few ideas over my bow please!
     
  2. tom.plum

    tom.plum Screwfix Select

    have you connected then up correctly ? some have a tube that comes in at the bottom and if its piped upside down it won't work as it should, o_O
     
  3. Glad its Friday

    Glad its Friday Active Member

    That's almost certainly your problem.
    As Mr Plum says, with many of the column rads, you have to ensure that the flow goes in the correct end. Often there is a bit of metal on the inside of the rad that you have to knock aside to get the flow through the rad right.
    Best go back to your rubbish bin and dig out the instructions and check. :(
     
  4. Christian8888hyde

    Christian8888hyde New Member

    Thanks for that, but I don't think they can be upside down, they came with air vents in which is obviously the top!! I don't know if they have inlet and outlet specify ports, but the inlet is opposite the air vent end! I have another radiator to this identical in the living room and it's bouncing!!
     
  5. Christian8888hyde

    Christian8888hyde New Member

    I'm not sure or aware of that bit of metal ill have to invest age! But as I said to tom plum, I have an identical radiator in the living room that is pipe exactly as the one in the bedroom. The mystery to me is why it gets hot and the cools as the rest of the house warms up!!! It just like the TRV'S are kicking in, but I've got them wide open! One other thing I did was to listen to the radiator with a stethoscope when it was heating up you could hear flow, when is was cooling it was as quite as a mouse!! I'm confused!!
     
  6. tom.plum

    tom.plum Screwfix Select

    the trv's don't regulate the temp of the water, they regulate the air temp of the room so they should never be slowing the water flow down, they're open or closed, but out of curiosity take the heads off and see if there's any change, o_O
     
  7. Christian8888hyde

    Christian8888hyde New Member

    I'll give it a whirl!! Milky bars are on me if that's the problem!!
     
  8. sam spade

    sam spade Active Member

    Do you really mean upside down, i.e top to bottom, or do you mean that the flow and return are not the right way round?
     
  9. tom.plum

    tom.plum Screwfix Select

    I mean upside down Sam, the flow and return would make a differance at first cos the cooler water will be comeing first, but after half an hour or so the temps balance out and it would't be noticed, but if the rads upside down and it has one of those tubes inside, it can't work properly, but hey its only guess work, its sure a strange case, :confused:
     
  10. sam spade

    sam spade Active Member

    Has the system been balanced since you installed the new rads?
     
  11. sam spade

    sam spade Active Member

    But the tube also has to be on the flow. so it directs the water up to the top of the rad. If it was on the return it wouldn't work.

    A TRV is not like a switch on or off, open or closed. They are more like the cruise control on a car. You set the required room temperature and the TRV adjusts the flow through the rad (which changes the rad temperature ans consequently the output) so it gives out the correct amount of heat.

    The problem is that so many TRVs do act as on/off switches, but this is because the system is not correctly balanced.
     
  12. Christian8888hyde

    Christian8888hyde New Member

    Sam, Tom plum
    I took the heads off the TRVS in both bedrooms with the problem and to my utter surprise the than are working!!! Well at least for the last two days!!! I've been to costcos for the Milky Bars!!!
    I have now refitted them, but have they are fully open! And things still seem to be ok!
    Why are the TRVS shutting down? Surly they only work when the air temp raises! Both radiator trv's sets are new! They were from columnrad at £75 a set! !! Can't believe they are defective???
     
  13. Christian8888hyde

    Christian8888hyde New Member

    The radiators aren't upside down! The radiators are from columnrad the come with a stop end (lacquer coated) and a air vent in the top!!
    I don't know if they have a inlet and outlet end? Because you can reverse the radiators,the wall brackets clamp to them so you can put them on either side!
     
  14. Christian8888hyde

    Christian8888hyde New Member

    I've tried to balance the radiators working away from the boiler! On the main radiators I set them so there was a delta t of 12 degrees??? The smaller rads were less than that or off!!! Some of the lockshields were far from microadjustable! The delta t figure was something I read somewhere?? I was wondering if there is a different figure for different size rads?
     
  15. tom.plum

    tom.plum Screwfix Select

    £75 a set ??????? kinell, thats the problem they're too clever ( or trying to be) get a cheap set off screwfix £7.99 and send those buggers back, :):)

    ps sent my milky bar to toms tavern,
     
  16. Christian8888hyde

    Christian8888hyde New Member

    They look good!! Next step is to swop the TRVS heads with the two radiators downstairs! If the bedroom ones work downstairs it ain't the TRVS and just a coincidence!!
     
  17. Christian8888hyde

    Christian8888hyde New Member

    20150127_225701.jpg Real pretty! Wouldn't you agree Tom Plum
     
  18. Christian8888hyde

    Christian8888hyde New Member

    Attached Files:

  19. tom.plum

    tom.plum Screwfix Select

    ahh I see where you get the price from, you won't get those for £7.99 :)
     
  20. Christian8888hyde

    Christian8888hyde New Member

    They'd be worth every penny if they worked!! Best not say too much til I've done the next test!! I'll keep you posted!!
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice