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How to remediate a badly-designed central heating system?

  • 24-11-2021 9:38pm
    Registered Users Posts: 4,722 ✭✭✭ Dilbert75

    I'm renting a dormer bungalow and the landlord told me when I moved in (June) that the radiators upstairs "sometimes get airlocked" and that he'd probably get me an electric heater. Now that the cold weather has come, I realise that means that that means "never work". It was 10 degrees in my bedroom this morning, and peaked at about 12 degrees in the middle of the day. It was 9 degrees in the bathroom and peaked at 11 in the middle of the day. This is with the heating on 6 hours a day. In the short term I can use electric heating but it sticks in my craw a bit that I've oil fired heating on and have to pay for electricity for it too (and he had committed to a high cost tariff before I moved in, so I'm stuck with it).

    So it turns out that the plumber who installed it when it was being built ran the pipes to the 3 radiators at the front of the upstairs over the ceiling of the upstairs, so the hot water goes to the 3 radiators at the back of the house but not at the front of the house - presumably it gets to the apex of the pipe and then stops. From what I can gather, it's one pair of pipes to the middle rad, branched each way under the floor from there.

    The landlord and his plumber have both commented on how it could never work the way it is. I'm not sure what they've tried already and I know he doesn't want to spend big money on it (spent a fortune fixing the place after the last tenant). it's so cold that I don't know that I can have my partner and her kids stay over even the odd night but I have zero alternative rental options so I want to see if he'll bite on a suggestion of a straightforward way to remediate it, if such a thing exists.

    The way I'm thinking is that there are three ways to connect those three radiators at the front of the house to the heating system at the back: over the ceiling, under the floor (timber joists) and around the periphery.

    1) Over the ceiling - not working with natural convection, so would fitting a small circulating pump to that leg force hot water over?

    2) Under the floor - would have been best at install but I'm not sure there's a clear run from front to back between timber joists, and there's no access to the crawl space at the front, so it would entail ripping up floors / putting a hole in a wall (which I doubt he'd be up for). If it were my house, I'd totally do it but it's not.

    3) Around the periphery - the crawl space at the back extends to the gable at one end, so I reckon that two pipes could be put through the back bedroom, into the front bedroom and connected into the existing rad - the question is whether, if the up-and-over loop were closed off, this would then allow the 3 rads to be fed from the end rather than the middle.

    Any thoughts?

    Post edited by Dilbert75 on


  • Registered Users Posts: 3,392 ✭✭✭ 10-10-20

    I'm no plumber, but since you asked...

    1. This would be my preferred option.
    2. This option was not initially chosen for some reason. That may be an indication.
    3. It seems like a fair bit of work, but may be viable if you can access the main feed & return pipes. Could you pull the pex pipe out of the attic to make up this run through the crawl-space?

    Option 4 may be that there is an air-lock at the highest point. I'm not sure that auto-vents are recommended in that instance, but would that be an option to fit?

  • Registered Users Posts: 30,628 ✭✭✭✭ Lumen

    I realise this isn't helpful but two things stand out:

    1. The landlord re-rented it in the middle of the summer when the crap heating wouldn't be noticable, and warned (in a misleading way, mind) at the time the upstairs heating was dysfunctional. And you took it. It's not your fault, but the lesson the landlord has learned is "I can rent this the way it is".
    2. Old dormers are often a total heat loss nightmare. Even if you got the radiators working it would probably cost you a fortune in oil to keep it warm up there.

    I would seriously look for somewhere else. Is there really nowhere?

    That said, you possibly have peak leverage with the landlord right now, because if you leave any potential tenant will experience the ice box for themselves.

  • Registered Users Posts: 9,775 ✭✭✭ Effects

    When you say over the roof, do you mean above the ceiling?

  • Registered Users Posts: 4,722 ✭✭✭ Dilbert75

    Thanks. I'm also no plumber so I'm trying to apply what little knowledge I have to fixing the problem.

    There are auto-vents fitted, I believe, but they're apparently not having any effect.I'm not sure it's an airlocking problem - I suspect that the water is getting pushed up to the top but maybe the pump isn't strong enough to force it back down to the radiators, or maybe it's just taking the easier path through the other radiators. Balancing the system might help, but I'm not sure.

    I'm not sure if the house started life (in 2004) with the upstairs converted or if that followed later but the plumber who plumbed the upstairs at least is a moron (unfortunately I'm related to him, so I may be biased!). My only reservation about the pump idea is that it's on a zoned system, so there's a little bit of complexity in only have it run when the zone is open but not a big deal (landlord is an electrician).

  • Registered Users Posts: 4,722 ✭✭✭ Dilbert75

    Yes, I think you're right on the first point. It was very much by-the-way, implying that it's a minor, occasional problem when it's really not.

    I'm not a cold-blooded creature so I think if the radiators were working I'd be happy enough there. And I'm not exaggerating when I say there really is no alternative - any half-habitable house gets snapped up around here and you're left with a choice of apartments in developments with...."reputations". And I worry I might have a problem getting my deposit back if I leave before the year is up.

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  • Registered Users Posts: 4,722 ✭✭✭ Dilbert75

  • Registered Users Posts: 30,628 ✭✭✭✭ Lumen

    OK, well if you have no other options and the landlord won't be gently persuaded to fix it....

    According to Threshold (

    Timeframes for Repairs and Maintenance

    The Minimum Standards Regulations do not specify timeframes within which a landlord/agent must carry out necessary repairs and maintenance to a rented property. Threshold suggest some timeframes below which serve as a guideline only. However, it is important to know that it may take longer depending, for example, on a trades’ persons availability, ordering parts/replacements etc.


    Urgent: These are repairs that need to be carried out quickly to allow the tenant to enjoy their tenancy and to avoid damage to the house. Examples of urgent repairs

    are: broken fridge, cooker or shower; heating system not working (particularly in winter), build-up of mould.

    Suggested timeframe for urgent repairs: 3-5 days.

    Clearly the house has a heating system and it's not working particularly in winter. I doubt the landlord can get out of his legal responsibility to fix it by supplying you with an electric heater, but you might want to give Threshold a call to get some advice.

    I'm not sure you should get sucked in to suggesting solutions. It's his legal responsibility to maintain the home which you pay him for.

  • Registered Users Posts: 9,775 ✭✭✭ Effects

    Sounds like a real pain in the ass alright. Does the system have separate valves to control upstairs and downstairs, or is it all just one circuit?

    I'm presuming it's a sealed and pressurised system, rather than gravity/tank fed?

    Can you turn off all the other rads, and see if it will then go to the ones currently not working? Make sure to note how many turns to shut the other rads off, so you can reverse to the previous setup.

    Might also be worth getting the thread moved to the plumbing forum.

  • Registered Users Posts: 12,042 ✭✭✭✭ Varik

    as above, that single zone, and close off all the radiators except the nearest blocked one.

    Should be a valve on the boiler to add water to the system with that and bleeding you might get the air out if it's that after enough attempts doing and redoing it.

    After that maybe a plumber with a compressor would clear it.

  • Registered Users Posts: 4,722 ✭✭✭ Dilbert75

    Thanks folks. I'll keep the Threshold option in mind. I'd prefer to not go nuclear with the LL but it will have to be an option.

    It is a sealed, pressurised system and I do know how to pressurise it. I've been able to bleed it - well, no air comes out, just water.

    Plumbing forum is a good idea - didn't know there was one!

    The idea of shutting off the other zone makes sense to me - I'll just have to see if the upstairs zone is fed directly from the boiler or if it's fed off the downstairs zone. Good advice on that too.

    I really shouldn't have to deal with this myself alright. Part of me likes the problem solving challenge but at the same time it's very stressful.

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  • Registered Users Posts: 30,666 ✭✭✭✭ listermint

    Tbh, your probably doing the right thing. The advice about leaving, finding somewhere else or going to threshold is all well and good in regulation world. Here in the real world there isn't homes to rent available the market is extremely limited, the landlord will get their back up and there would be months of cold until any resolution is found.

    Trying to solve it amicably and with some fault finding yourself and testing is the most sensible practical advice.

    I'd start first by seeing if you can balance the radiators. That means knocking all of them off and working back through the system one by one. There's various YouTube on methods for this.

  • Registered Users Posts: 12,042 ✭✭✭✭ Varik

    Even within the same zone just close the valves on the radiators themselves except for the first one that's bad so you've only to bleed one to get the most of the air out.

    Even if water is coming out at first the air will be at the high point so it won't be in the radiator itself yet, so you've just to keep going bleeding and pressurizing.

  • Registered Users Posts: 4,722 ✭✭✭ Dilbert75

    So, the LL got a plumber in (because of another, separate problem) and they had a look. They figured that the hw cylinder was starving the heating, with the circ pump possibly not up to the job of pumping to the top of effectively a 3 storet house. There's a valve on the return from the hot water cylinder and they shut that almost fully off. Li and behold the feed pipe started getting hot and the front rads did too.

    For some reason, it didn't last long though. With nobody touching anything, it stopped working after a week or so. So last week I spent a while tweaking trv's (balancing valves are mostly seized). Most are now turned fown to almost nothing but are still heating adequately and the front rads are back heating...for the moment anyway... Hopefully this won't be a constant dance...