Our house was a new build 14 yrs ago, we are original owners. Gas central heating, cheap and cheerful as fitted throughout the estate, and the pipes are all micro plastic things. We added an extra 3 rads about 10 yrs ago when we did a loft conversion, which was just within boiler capacity. Hot water is gravity hot cylinder setup.

Boiler has had a few problems over the years and we have had various cold spots in rads. System is under a Scottish Gas maintenance contract which has paid for itself tenfold….

System was powerflushed (twice) last year to try and sort out coolish radiators, to no great avail, with some of them still taking 3 or 4 hours to get proper hot.

The service engineer is coming tomorrow for annual service and I want to get some ideas about sensible cost effective ways to sort, Ripping out all the thin diameter pipes and replacing with proper bore ones would do it I expect, but that is major upheaval to walls, floors etc. Wondering whether a newer bigger boiler would solve it ? If so is sticking with gravity water cylinder best option, or would a combi one be better/cheaper/more to setup ???

I know little about heating, apart from paying the bills 🙂

on mine I had the cold rads thing. It was the cold water feed that had blocked up the pipe where it split meaning I had about 10% flow downstairs and 90 up. stick a magnet on your pipes and see if they are magnetic = sludge buildup. Cant get it out with a screwdriver after ive cut it out so a powerflush wont touch it.

Small bore pipes won’t cause issues like that – build of crap as above will.
Small bore helps as there’s less fluid in the system to move/heat so you actually get a faster warm up time.

the powerflush guys reckoned that system seemed quite clear, which makes me wonder if the boiler is just too old/crap … pump has been replaced a few times, so can’t imagine it’s that.

Are they the furthest rads in the system? I take it the basic stuff has been checked – pump settings/efficiency, balancing the system properly etc.

If you isolate the coldest rad by turning off the lockshield valves to the rest, does it get hot?

not furthest away, but I think the builders arsed up the route when they built the house anyway. All basics have been checked a fair few times. Isolating coldest does work, for a few weeks/months, then they start cooling at the base again.

flow issue then.

blocked or pump.

thanks. Doesn’t sound like a new boiler is the solution then…

Could be – “new builds” are notorious for being built to a price.
The whole estate here is renowned for poor boilers – Ideal is the make.
British Gas hate them, they spend so much time/money replacing boards and pumps because they are junk owners have taken the builders to court recently.
Same as the radiators – the literal bare minimum that the calcs say they can get away with – useless basically.

Are all the rads on TRV’s?and are they set sensibly (i.e. all on a low-mid setting, not one on high somewhere stealing all the heat?).

We’ve got a truckload of rads in out house, some so big/heavy I can’t even lift them off the floor let alone move them on my own. But after taking them all off the walls and jetwashing inside, then running couple of bottles of CH cleaner through them they all get hot in some sort of order as the ones closest warm up, the valves close, the next one warms up etc. No balancing required as the inherent imbalance is corrected for by the TRV when those rooms get too hot.

I have 30yr+ old Microbore in our house. Rads warm up uber quick, no problems.

hammy – think you have hit nail on head

TINAS – yes, all on TRV’s and balanced out, bizarrely, the only one that isn’t on a TRV is in the ground floor hall and is one of the ones that takes hours to get warm at base, suggesting poor flow… they have had it off wall and cleaned out, so last time they reckoned pipe was a bit blocked, then it got ok for a month, now crap again…

matt – lucky you ! 🙂

one in hallway will be the one that the thermostat needs to work.
If there was a TRV on it the boiler would end up in a demand loop.

ah, you can see how little I know about it 🙂

Will see what they reckon tomorrow.

Cheers

Here’s a wee story about plumbing: back in about 1980 a pal of mine was looking around for work and he somehow ended up on a building site. The bloke asked him if he could do plumbing and he lied “yes”. Next morning he found himself with a borrowed plumbing kit working his way through dozens of houses on the estate; he reckoned it was pretty straightforward once you remembered the principles. After a week or so the boss came up to him with a big box of brass things, saying: “You’ll be needing these as you’ll be running out by now.” My pal had no idea what they were so he casually replied: “Oh… never worked with that model before. Where does that one go?” The boss told him and he shot off back to all the houses he’d finshed to install the vital brass bit he hadn’t installed first time round.

After that job he and his wife sailed their tiny yacht across to Antigua and he ended up instructing at a dive school….

I **** HATE PEOPLE LIKE THAT.

My house was built at a similar time and had a potterton boiler in running on cylinder hot water and a cylinder in the loft and microbore pipes all through.

Best thing I did was replace it with a Worcester Bosch combi boiler, saved me about £30 a month over the last two years and has a decent warranty to back it all up and I got the space back from removing the tanks.

Rads all warm up nice and quick and they installed a magnaclean when they did it to help reduce blockages from the rads rotting away.

somouk – sounds very similar, same make of boiler too. Was it simple to convert to combi ? would you be able to give ballpark of what it might have cost ? (we are 4 bedroom, 14 radiators).

You need to make sure they are properly balanced first.

Mail me on timATj-twren.eclipse.co.uk and I will send you some notes on how a system should be balanced……

had a few folk round, still waiting the British Gas quote. Consensus seems to be poor initial design and installation with drop micro pipes, not aided by cheap Potterton Boiler which was on it’s output limit (in all the houses in the estate and proving problematic for others too)) .

Suggestions mainly new boiler (current 24kw being replaced with 30kw Ideal Logic (not combi) with 7 yr warranty) with filter, balance, upgrade gas piping etc. Best price so far all in is £1900, which is from a guy who comes recommended.

does this appear a good deal ? Google suggests the boiler retails at around £900 so I guess trade a chunk less.

Is your central heating pump variable speed? If so, it might be running too quickly, pushing the water through its loop not giving it adequate time to reheat as it passes through the water jacket? As a thought.

Blockage also possible.

Why go for the cheapest deal? You’re currently dealing ( and for some time) with the consequences of a cheap system. Someone above mentioned that Ideal had the worst reliability record, yet your considering a quote that specifically mentions that manufacturer. Observation really.

Clearly you’re not going to deny the tradesman his profit, so could you just ask him for alternative make with a revised amount? IME, as a once self-employed, tradesman the customer rarely did themselves favours by checking prices on the Internet. I would suggest they bought the goods and I’ll install, but would not take responsibility for anything other than that, problems would be charged extra and I would generally increase my labour rate to compensate for them not giving me an opportunity to make it financially worth my while. Wisdom really.

Anyway, hope you get it all sorted and hopefully it’ll work much better.

I am getting a new boiler fitted this week. Intergas HRE 36/40 combi boiler costing £2313 this includes a magnatex cleaner thing and altering the pipework as the new boiler is in a slightly different location from the existing one.

Just make sure whatever you have fitted it IS NOT an Ideal 😯

I think 10 years is about the best you can expect from a cheap new build boiler. Ours lasted about 15 years and it was a half decent Potterton boiler. We replaced it with a new one and converted from a vented system to an untended system and it is a different world and far more efficient too. If I were you, unless the plumber finds something obviously wrong, then just aim to get it replaced. Although our old one was still working fine, it was quite noisy and took a good 10 minutes or so to warm up the rads – this one is silent (where do those clicks and bangs come from?) and the rads start warming up almost immediately.

Iain I assume you tried bleeding the radiators?
I’m going through the same process with one of my rads at the moment. It was old and couldn’t be bled so I’ve replaced it but its still not making much difference. Just going through the process of trying to balance the system. Anyway, if your system work originally then replacing the pipes IMO isn’t the answer. It’s either build up of crap in the system from the radiators corroding or possibly a faulty TRV/boiler pumps. After your system is power flushed they should add an inhibitor to prevent the system corroding internally. If this wasn’t added sludge will start to build up again causing the same problem. Potterons a decent enough boiler and you should get more than 15 years from it. A decent 30kW combi boiler will set you back between £800-£1300. I’d stay away from brands like Vokera and Ideal. I’d also point out that British Gas might offer you upto £400 off a new boiler, but their install prices are notoriously high so I’d shop around.

lots of good points, appreciated

update – various quotes in, managed to get the British Gas one down to about 30% over the indy one, with a 30kW Glowworm Boiler, 10 yrs guarantee, and extra control valve on the HW side, some updates to flue and electrics, and a Hive controller. (2.6k vs 2k indy (Ideal Logic))

About to press the button on this, given that there is I think better peace of mind and comeback for future should we have issues with it.

any final advice ? (guy is coming round after work to book in etc)