Through a process of elimination I've worked out that I've a blockage somewhere in the heating circuit of my vented central heating. When the 3-port valve is totally h/w, the boiler works fine and we get hot water. When the valve is totally c/h, the boiler thermostat cuts the boiler out about 1minute into it. Every time. Quite an old central heating system, and it seems to be a single fee/return all the way round (i.e. one 15mm passing each rad, teed off twice to each side of the rad). The piping is all under the floorboards (of course, it'd be too easy otherwise!) so any ideas HOW I can find where the blockage is? I've read about using a magnet - does that have any legs, although of course I can only get to the above-floor pipes, of which there aren't many. I considered hiring a powerflush machine but am of the view that the blockage is probably quite significant as the boiler really doesn't last more than 1min on c/h before it pops. I'm proper skint and don't think I can afford an expert without selling one of my kids ... please ... any ideas anyone would be VERY VERY much appreciated
Ideas on HOW to find the blockage?
- Thread starter cinman2003
- Start date
Sponsored Links
Having read the boiler pops if the temp drop isn't at leat 11degrees then I've stuck the 3-pos valve on A+B so it's servicing BOTH the c/h and h/w. The idea is that the heating "eventually" get's warm at least, even if it takes hours, then when I stick the valve over to c/h it should be okay. Worth a shot I s'pose as I'm tearing my hair out right now, kids freeze at night, missus bugging me to do something and I'm about to be redundant so trying to save money
... that I've just had cleaner in it for over 2 months (too scared to remove it over winter in case "this" happened!) It should be as clean as a crappy old system gets. I've removed 2 rads and flushed 'em in the road, and they were kinda cruddy, but considering (when this is fixed) fitting a magatech or spirocoil jobbie to catch the mess.
Sponsored Links
Your logic has one little flaw.
If you put cleaner in a dirty system and leave it there, the dirt stays in too.
Most cleaners stop working after a few weeks, so it may dislodged some crap from all over the system which then happily congregates at the lowest point of the system.
I've just flushed the whole system and stuck some inhibitor in. Same prob, but the water that came out wasn't that dirty. I'm presuming something's either built-up or just some crud's jammed downstream. I like the hosepipe idea, 'cos I could effectively go from rad to rad until I find one with little or no flow, which would point to the blockage being before or upstream of that rad, presumably? If they all flow, then it points to the boiler return?
That's because the cleaner stopped working a month ago, so now the dirt is sitting on the bottom somewhere.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
