New radiators needed or just new valves?

Discussion in 'Plumbers' Talk' started by Little cabbage, Jan 5, 2014.

  1. Little cabbage

    Little cabbage New Member

    Hello,

    I'm hoping that someone can advise me about a problem with our central heating. We moved into a 1920s detached house two months ago and have found that the boiler cuts out every 2-3 weeks. A heating engineer has diagnosed this as being due to the radiator valves leaking, which causes loss of pressure in the system. We have open taps on the boiler to top up the system, but the engineer says we can't keep doing that as it will draw corrosion-contaminated water into the boiler each time, which will eventually damage it.

    The radiators are probably from the 1970s or 80s. My question is - should we just replace all the valves to stop the leaking (quoted approx £250 plus vat), or would that just be putting off the inevitable? Should we just bite the bullet and replace all the radiators as we are planning to be here for a good 25 years!? The quote for that is approx £1400 plus vat. Would new radiators be more energy efficient and therefore save us some money that way?

    I'd be grateful for any advice, thank you.
  2. joinerjohn1

    joinerjohn1 Screwfix Select

    Probably best to replace everything. ;);)
  3. Little cabbage

    Little cabbage New Member

    Thanks, can you explain why please?
  4. joinerjohn1

    joinerjohn1 Screwfix Select

    Well, the rad valves will be the same age as the radiators (or should be) It could be a combination of valves and rads leaking. Radiators could be sludged up (in the bottom of them) What sort of boiler do you have ??
  5. Little cabbage

    Little cabbage New Member

    It's a combi boiler, roughly 7-8 years old, made by Ferroli. Is it bad to have sludge in radiators?
  6. teabreak

    teabreak Active Member

    My two pennyworth would be unless you have rads cold at the bottom and hot at the top (sludge symptoms) or bad rusting / pin holing of the rads, just renew the valves. Valves often leak after a very short time, rads last donkeys years.
  7. Little cabbage

    Little cabbage New Member

    I've just checked, and they feel hot all over. And I can't see any rust or small holes either. Are newer radiators any more energy efficient? I think a couple will need replacing anyway as they're too small for the size of room.
  8. joinerjohn1

    joinerjohn1 Screwfix Select

    Can you see where the radiator valves are /have been leaking?
  9. teabreak

    teabreak Active Member

    Any tiny saving from a better rad would be offset by the cost, By all means get the smaller ones changed, you can ask your installer to treat the system with a cleaner something like Sentinel X400, which can be run for anything from 2 hours to three weeks in the system before flushing out according to how bad it is. Chances are a few hours would be enough as yours has no symptoms.
  10. Sean_ork

    Sean_ork Screwfix Select

    if you've got K1 rads then a K2 or K3 will impart heat (from the CH system) into the room much more efficiently - but it won't save you any money (unless there's a lot of heat being lost on route to the emitters)

    you'd be very unlucky to have every valve leak - if you can find the leaky 1, or 2 a simple tighten might solve the problem

    get it dosed with a cleaning agent and have a filter fitted - and clean the filter (not really a traditional filter) every few days for a couple of weeks after dosing - then once a week until you get bored - if you are really keen you could remove the rads and manually flush them out with a standard mains water garden hose - or pay someone a few £100 to do the same - but the fact that they all get uniformly warm is a sign that they aren't even partially blocked

    don't just assume that it all needs replacing simply because a plumber tells you so
  11. Little cabbage

    Little cabbage New Member

    Thanks for the replies so far. Joinerjohn - one of the radiators that we know for sure leaks, gets wet copper pipes below the valves on each end. Another one has wet carpet around the copper pipe. I think we'll try and find out for sure which leak and which don't, and just replace those valves.

    Having googled what K1, 2 and 3 rads are, most of ours are double panel with fins.

    Thanks for all the advice - much appreciated.
  12. Devil's Advocate

    Devil's Advocate Well-Known Member

    Little Cabbage.

    If the rads themselves don't leak, there's no need to replace them. However, we can't tell from here whether they are partially corroded through and are likely to leak in due course - hopefully your plumber will be in a better position to judge?

    You mention that one rad at least does leak? Why? Is it rusted through? Is the painted surface bubbling? Can you see where the leak is?

    Bear in mind that the rads will be rusting from the insides, so if one has rusted through, then they are all very likely to have some level of partial rusting inside. You might be able to stop that in its tracks by flushing the system as suggested above and then adding inhibitor - that could well be enough to prevent any future problems, but it's impossible to be certain. For instance, your sealed system runs at around 1 bar pressure. If, for any reason, that goes up to the 'safety' level of 3 bar (and it almost certainly will at some point...), that could be enough to 'blow' the thin corroded shell which has been holding on.

    Bottom line - we can't tell, and good chance your plumber won't be able to either. So, a bit of a gamble here. As there is in any system.

    Will newer rads be more efficient? Not in its use of energy, no. But they could be capable of delivering more heat from the water into the room, but that - of course - means more hot water needed, so no actual energy 'saving' as such.

    Some things to consider, though; I'm guessing your Ferolli is a condensing boiler being only 7 years old? In which case larger rads running with cooler water will give the same heat out to a room, and this will then save you some energy as your boiler will be running more efficiently - doing more condensing, so removing more heat from the hot flue gases. So, if you do need to replace any rads - particularly in the main 'living' areas - then consider going a size bigger (or more panels/fins etc.)

    I'm guessing your plumber has suggested TRV valves in most cases?

    Ok, here's a suggestion. I think what I would do in your position is (a) replace any rads that NEED replacing, and go over-size. But don't bother replacing any that seem fine. With the saving over new rads, instead (b) fit a system filter such as a Magnaclean/ Fernox/ Sentinel and get your plumber to thoroughly dose your system with a cleaner such as Sentinel X800 (the powerful one...) Actually, add the filter and cleaner now. Also with your saving, consider (c) fitting programmable TRVs to all rads in rooms which are only used at limited times, such as bedrooms, study, dining room, etc. (Screwfix do them at around £35 each, I think). These can then be set to turn on these rads only when needed - eg: bedrooms at 9pm for a couple of hours and then at 6am for an hour, etc. and they'll be off during the day and evenings. That way you should save a lot on gas.
    Last edited: Jan 5, 2014
  13. Sean_ork

    Sean_ork Screwfix Select

  14. Devil's Advocate

    Devil's Advocate Well-Known Member

    :D Yep - I saw you refer to them in your other thread.

    And only £25?! That's barely more than a decent quality normal TRV. Awesome!
  15. Sean_ork

    Sean_ork Screwfix Select

    that's heads only - ideal for anyone just wanting to upgrade as they include adaptors to fit every valve known to man - and it's actually £18.75 each as there's a buy 3 get 4 offer
  16. Little cabbage

    Little cabbage New Member

    That's all good advice, thanks. I think it is the actual existing valves that leak, rather than the radiators themselves, as the water seems to come from the connection between the valves and the copper pipe below. We thought we might tie loo roll around this area on all rads to assess which leak - not always easy to tell if it's a small amount of water just running underneath the floorboards.

    We mostly do have TRVs but quite old ones. I really like the sound of the programmable ones so I think we'll change to those.

    Thanks again everyone for your input - it all seems a bit clearer now!
  17. teabreak

    teabreak Active Member

    The trv's look intersting but read the reviews first lot of one stars complaining about noise.
  18. Little cabbage

    Little cabbage New Member

    Will do, thanks.
  19. Sean_ork

    Sean_ork Screwfix Select

    you'll also see a lot moaning about how hard the instructions are to follow :)

    the instructions are in very plain English - but there's lots of options and I can see why some would get frustrated and surrender, but that's not a comment on the quality of the instructions

    the noise a bit like a radio control servo, plastic gears on plastic gears and it's quite hard to hear - and it only does it for a few seconds whenever it changes temp - which might just be a few times a day

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