Just wanted to post on this thread in case, like me, other users come across it when trying to diagnose a similar problem with their HE 30 ISAR boiler.
Like Niggelvr6 I was repeatedly woken up the other night to what sounded like a lorry passing through my home. It was in fact the boiler making this sound when the hot water on my combi boiler tried to kick in, as it periodically does for a few seconds every hour or so when not in use.
Had also heard the noise earlier in the evening when I took a shower, the water wasn't as warm as usual. The central heating didn't seem to be producing this noise. By morning boiler was displaying LF error and would not restart.
This is not the first time it happened. 3 months ago I had the same problem having heard the boiler periodically make the same noise, which eventually got worse and more frequent. The central heating was also responsible for making the horrid noise on that occasion not just the hot water.
I had a plumber come over as the discharge pipe was leaking, he stuck a 'snake' down the pipe to clear it out and there was a lot of grey sludge in the pipe, the leak stopped temporarily.
The boiler packed up 2 days later and would not restart. This time I called a boiler repairer who diagnosed as my plumber had done, that there was either a blockage in the pipe that carried both the waste from the discharge pipe and the condensate drain pipe (it so happens that both these pipes have been fed in to the 1 plastic pipe which runs under the bathroom and out doors) or the positioning of this pipe was such that the water wasn't able to drain out of it successfully.
I can't access this pipe for various reasons so the boiler was temporarily fixed by cutting into this plastic pipe and allowing the water from the condensate drain to pour into a bucket which I have to empty. Didn't get around to re routing the pipe as I should have done.
It's worked absolutely fine for 3 months. The last couple of weeks however the bucket hasn't been filling up with water and muggins here didn't do anything about it. 2 days ago the events in the first paragraphs happened.
I choose to call out an engineer through ideal heating. This cost £245 including all parts and labour except a replacement heat exchanger. For extra £55 I could extend this service for 12 months with unlimited call outs. There are certain exclusions such as clearing sludge in the system, plumbing issues etc.
I have sludge in my system and that is why my boiler has behaved like this. The trap and seal kit was so badly clogged with compacted dirt it couldn't be completely cleaned so i wasn't given a new one.
I need to powerflush my system, this is not included in the repair price but that was explained to me when i purchased it. I need a plumber to do that. I think prices range from £300- 700.
The boiler will stop again if i don't do this, possibly in weeks. I have read enough to suggest that these boilers are prone to getting clogged up, not sure if that's true but wanted to share my experiences with you in case it saves anyone time or money.
Personally i think i'm going to take the hit and replace the boiler and start again if i can afford to for piece of mind. There are other reasons for this which I won't bore you with, but have also read enough bad reviews to suggest the make is very poor. Then again I suppose nobody thinks to write when boilers are working fine.
Apparently my boiler was installed 8 years ago according to Ideal's records. This doesn't fit with was I was told by previous owner, then again they did mysteriously loose the installation certificate....
My advice is act quickly as soon as you hear any noise and hopefully before the boiler stops completely (not like me), and get your boiler repairer to check the boiler for sludge first and foremost.
Remember most repairers can't come the same day because they are too busy fixing other peoples boilers so it pays to not wait around. A trusted local provider is usually better and cheaper than going through a large company like Ideal or British gas.
