Non-motoring > Central heating Miscellaneous
Thread Author: bathtub tom Replies: 15

 Central heating - bathtub tom
The bungalow I've bought has three of nine radiators replaced. Switched the system back on and the boiler was cutting out. Found the pump wasn't turning. Got it going and it was making an awful noise for a while, sludge I presume. It's a gravity system, non-condensing boiler, no t/stat, but TRVs on most rads (bathrooms don't have TRVs). I'm expecting to get the boiler replaced in the near future. Do you think it's worth draining and re-filling the system a few times to try and flush out the muck?
 Central heating - sherlock47
Probably get some desludge chemical into it first and then flush. I used a hose to reverse flush radiators which was fairly effective. However prepare yourself for desludging to discover all the pin holes in the pipes and radiators!

If you connect a hose with mains water pressure to the system, make sure the header tank is empty and that the overflow is effective.
Last edited by: sherlock47 on Sat 23 Apr 22 at 09:41
 Central heating - James Loveless
I'm in the middle of a major issue with central heating. Some weeks ago I realised many radiators were not hot all over. Bleeding air made no difference. Since then my plumber has fitted a new pump and flushed the whole system and also removed each radiator, reverse flushing it while beating it with a rubber hammer. One radiator still had problems and was replaced. Now the boiler seems to have failed, an eleven year old Vaillant. I'm just hoping that all will be well when it's replaced and that there aren't any further problems.
Last edited by: James Loveless on Sat 23 Apr 22 at 10:00
 Central heating - Fursty Ferret
If the system is drained then Hozelock connectors will usefully screw onto a radiator valve if you wanted to flush them.

If it's just you then do it in situ but get the expensive connectors and check that they'll hold the hose under full mains pressure lest you spray black sludge over your house.

If there's two people then carry each radiator into the garden and do it there.

If you're feeling flush and you think they're not in good condition (pin hole leaks etc) then just replace them. Not desperately expensive.
 Central heating - sherlock47
Worth a read, when was the house built?
Last edited by: sherlock47 on Sat 23 Apr 22 at 10:12
 Central heating - bathtub tom
Had a couple of quotes to replace the (30-year-old?) boiler and rads, with an Ideal Logic Max 30Kw.
Any comments on this boiler? I understand it comes with a ten year warranty and as we're in our 70s...........................................................
 Central heating - CGNorwich
Had the same make and model installed just over a year ago. Not much to say about it really. Works fine, no problems. A lot quieter than the old boiler it replaced.
 Central heating - Fullchat
Had one fitted in the daughters house. Does the business. For the 10 year warranty you do pay a bit more on the base price. Has to be serviced every year to maintain the warranty.
Plumber friend says its really easy to work on and the parts are easy to get if required.
 Central heating - smokie
I replaced an older boiler a couple of years back and it has highlighted a problem elsewhere in the system. It's a Vaillant but that's probably irrelevant. it has many more sensors and fail safes than the previous one, and regularly trips out because the inflow and outflow temperatures are too far apart.

It apparently gives it three seconds (or three attempts) to correct itself then shuts down with an error.

The first we know is the tank only has enough hot left in it to cover the time it takes to lather up, so rinsing off is under cold.

The engineer reckons the pump is a bit slow starting, which is going to be another £200.

There was nothing wrong with the old boiler (except uneconomical) and I wish I'd not bothered spending the £2k or whatever it was to change.
 Central heating - sherlock47
10 year warranty - will only be any good if the manufacturers requirements are followed to the letter and the the system design meets their recommendations along with annual services and system chemistry checks. It maybe worth getting your quote from one the manufacturers installers, not just any local (trusted?) plumber. From what you said earlier it sounds as though a very thorough power wash will be required.
 Central heating - Crankcase
>> 10 year warranty - will only be any good if...

And the parts are still available, and the warranty provider is still in business, of course.

My brain would say if it just comes with the warranty, hurrah, hope it works if ever needed. If it's an add-on for £500, well, maybe. And if it requires rigourous things like only certain plumbers or chemicals at precise intervals, well, maybe not then.
Last edited by: Crankcase on Tue 26 Apr 22 at 07:46
 Central heating - smokie
AIUI there isn't a lot to change in them anyway. It's pretty much all on one board apart from some sensor. But I like having the manufacturer extended warranty, and it works for me as I get the thing serviced each year anyway which is the main requirement.

IIRC the power flush at install time was a warranty requirement anyway.
 Central heating - bathtub tom
The (surprisingly affordable) quotes I've had so far include a power flush, nine new rads, magnetic filter and chemical treament.
 Central heating - Zero
Asomg as you steer clear of the national names, it's good value for money over 10 years
 Central heating - Fullchat
With Ideal you can book your services through them and they maintain the servicing record. So if something doesn't comply to their requirements its not your fault.
Things got a bit out of kilter with Lock Down but back up to speed now.
 Central heating - James Loveless
An update on my issues.

The boiler has now been replaced. There is apparently some shortage of Vaillant boilers at present and my plumber's suppliers gave him the run-around with them being impossible to obtain, long waiting lists etc etc. I went online and a few days later the new boiler was delivered.

Cost so far: £1,400 or so.

What is supplied doesn't include a flue fitting and a few other essential bits; my guy also fitted a pressure release valve between the c/h and hot water circuits, and gave the system yet another flush. The extra bits plus one day's labour came to £1,140.

Total cost: £2,540.

What had killed the old boiler was a near-complete blockage near the boiler itself, which flushing the radiators had probably caused or worsened.

I compared the bills to the cost in 2008 for a boiler replacement, in the house I rent out: £3,018. The cost to replace the boiler here in 2010: £2550. It seems this time I have done OK, allowing for inflation.
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