3 Feb 2006
Reaction score
United Kingdom
I purchased a full central heating system in April 2005 and opted for a Glow worm 30CXI boiler. I have had nothing but problems. Three new heat exchangers, one new circuit board as it blew and new overheat sensor. It has been flushed twice, but still having problems. According to Glow worm there is dirt in the system and it has caused ALL these problems and now refuse to repair it! The boiler is apparently made by Valliant so that's their problem. The system was not installed by Glow worm so installation problems are not their's either. What do they do exactly? Anyone had similar experience?
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First & foremost problem is with installer (still u/g until april) has it been flushed properly (byusing a machine with the help of chemicals)
I did the glow worm training recently, thought they seemed to be a decent bit of kit, especially now vaillant are involved.We now fit them & so far no problems. A lot of newish boiler problems do stem from incorrect commissioning/cleaning. Lets face it, how many installers have time to spend giving the system a good clean. I spent a day cleaning my parents, haven't been back yet[1 yr]. There are 2 types of gas operative, srew 'em to the wall & f**k off, or spend your life fixing 'em. Anyway I know that's not solving anything, but for my money get the installer back, I don't reckon its the boiler.


Milk, no sugar ta.
It has been flushed twice
What sort of flush? All day with a machine, or jist a fill and empty?

Depends who do what flushing and when, and what guarantee was given. With Fernox even, saying you leave 20% or more grot in the system, I wouldn't give a guarantee that flushing would mean absolutely no issues with dirt.
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8) I could write chapter and verse about the 30cxi, basically its a **** boiler. I work for a company that is resposible for about a thousand of these and there is not one of our engineers would have one in there own homes.
the heat ex problem is more than likely the seals to the flue which are prone to leaking condense. never had a problem with the heat ex itself just the seals.
the siphon trap is badly designed and prone to blockage, again condense leaking.
the cartridge in the diverter valve again is prone to problems, we change on average 3 or 4 of these a week.
if i moved house and inherited one of these the first thing I would do would be rip it out and get another boiler.
when you say heat exch do you mean the d.h.w one these are prone to blocking especially after power flushing and is a common problem on all combis the flue condense have been modified because the early ones leaked ,from 2003 there have been no problems the vaillant ecomax used the same part and had the same fault. the new siphon has not given any problems since changing the cap and float, the divertor block has been upgraded because some grundfoss mouldings split so you do not need to worry about the problems mentioned by peirrot.
i have and will continue to fit these boilers and have a 38cxi at home without any problems
Is that because they gave you one for bigging them up on forums? Only kidding!
The secrets out will try vaillant or veissmann next worcester wont play ball
Well I'm the biggest advert for Buderus in Scarborough but they wouldn't give me the team off their sh1t. Don't know why I bother. The guys fitting Ideals are probably making a killing, who cares what happens in five years is the attitude, make loadsamoney now.
It seems quite clear to me that the original installer did not clean the system properly!

More worrying is that at least one person above implied that most installers dont spare the time to clean the system.

There is only one way to clean a system and that is to power flush it using the correct chemicals and that takes the best part of a day.

Even power flushing with the correct pump will not prevent some problems. I went to one and he had spent a day power flushing but had used the wrong chemicals, he said the shops sell it locally! That does not make it suitable. The shops sell it because its cheap and the installers dont want to pay for proper branded chemicals.

Even after power flushing, he then produced lime scale because he had not commissioned the boiler properly. He used the right equipment and spent a long time on it but did not have the skill to do it properly or use the right chemicals.

Here we go again.
It has been 4-5 months since an Engineer had to attend my boiler, which is the longest it's run without a problem!
I guess that is because i haven't actually had the central heating on, just the hot water. As soon as i put the central heating on two day's ago -guess what-----F14 error code again.
Now we have no hot water. I will have to call Glowworm again and they will blame the installer and say "It wants flushing". This will be the third time!
I think what i'll suggest is that I will pay for the system to be flushed---£500.00! and if the problem persists I will ask for Glowworm to refund my money as they were wrong!
What do you think?
All I can tell you is these are a nightmare for blocking up, went to a brand new installation recently on its second hw hx and now up for its third. It would be easy to blmae the installer for incorrect flushing but the whole system was brand new as a replacement for a warm air unit and the first blocked hx was within a month. I can't explain it except for something I heard recently about the wrong inhibitor being used causing excessive corrosion.
fitted a brand new system last year using 30 cxi.squelling after four months. so for the second time , i added a cleansing agent and allowed it to run for a while. then returned and flushed refilled and added x100.still squelling. g/w attended and said it was dirt in system , but sorted it by changing some part in the boiler with no charge to customer. :confused: :confused:
i moved in to house last year with one of these boilers (WHAT A PEACE OF S**T) i have had nothing but problems f14, f1, you name we have had it . the only thing you can do is get some decent boiler cover i had boiler cover with my barclys acount you pay about £10 for this acount and you get car cover boiler cover the lot its well worth getting as its saved me £800 last year and you get a thousand pounds a year cover on your boiler. if you have a GLOW WORM 30 CXI YOUR F**KED

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