So the boiler isn’t working again. Every year this seems to happen.
We have a vented heating system which is causing all sorts of problems as the radiators aren’t new and the system keeps filling with sludge. So the plumbers have suggested converting to a sealed system. Apparently this will fix everything, but I have heard that several times before. At one time the vented system was said to be the answer to all our prayers.
I was wondering if any of the resident DIY experts have any views on sealed systems. I’ve been told they can cause leaks because of the high pressure.
The majority of the “sludge” is, in fact “rust” which comes from the radiators and not the copper pipes. This comes from the fact that oxygenated water is available from the expansion tank in the loft, although this is usually dealt with by adding an inhibitor (which is also added to sealed systems).
There are other ways that you can prevent excessive build up, including inserting a “Magnaclean” or equivalent, which is basically a magnet inside a container, which can be cleaned on a regular basis without the need to drain down the system.
As for a sealed system leading to leaks, it’s possible but unlikely since copper joints are copper joints and should be able to withstand the increase in pressures involved.
Whatever the case, the system should be powerflushed (which is expensive), or have each radiator taken off and flushed through with water from a hose. If the plumbers are talking about replacing the boiler, then the system has to be cleaned out anyway since it is a requirement of the installation procedures anyway.
Personally, I’d not bother to replace the boiler unless necessary, but manually clean out the system in the way suggested and then add a system cleaner and magnaclean, let it run for a few weeks and then flush the system out again before refilling with inhibitor added to the expansion tank (top up once a year). This should last a good few years and prove just as effective as converting to a sealed system. IMHO, obviously
We used to have the problems Annie, so changed to a combi. Still have problems with silt and yet another power flush soon.
We would need to know more about your system. I’m no expert, but I have had so many problems, I am nearly qualified.
Much of what Dextrous says is correct. However, after flushing and fitting a magnaclean, you should not need to flush again.
And yes, add an inhibitor.
However, you’ve not explained properly. Is it that the boiler itself is not working, or the heating is not working due to sludge in the rads??
Some notes:
Don’t get ripped off with a powerflush. They will give all sorts of bull to justify the cost, such as the cost of the equipment etc. Truth is, a decent one is around £700, but they use it all the time and they last years. All you should realistically be paying is a days labour, plus a bit of travel time / mileage, for a decent reverse flush to be carried out. Plus the cost of a decent inhibitor like Fernox.
If you have a combi system fitted, as Dextrous said, you’ll need a powerflush as part of the works anyway.
The increase in pressure should have no effect. Another scare tactic to extract more money from the unknowing. Still have an inhibitor added to the closed loop heating circuit though.
If you go the route of a high efficiency condensing combi, you should find that your heating bill will drop quite a lot. You also gain space, as you will lose the hot water cylinder and both tanks in the loft.
Thanks I’m trying to remember what they were like when they were working. I think some would be cooler in the middle so maybe there’s a bit lot of sludge there.
They said the powerflush will sort it and that the sealed system will get rid of the oxygen that causes the rust so fingers crossed. I’m so fed up with heating engineers scratching their head and tutting when they can’t get it to work!
Sounds like they don’t know what they’re doing tbh.
If your boiler is only 5 years old (and still working) - maybe just go for the flush and get inhibitor added. Inhibitor prevents (to a point) the internal corrosion and sludge build up.
Don’t get ripped off on the cost of the flush though…
Hmm. This is new enough an installation for the system to have been power flushed through as per MI. Something is deffo not right as I’d have expected it to have lasted a fair few years and well over 5 before “sludge” became an issue
Sorry I didn’t explain, it’s the boiler switching itself off with a fault and apparently the fault is that the water pressure isn’t high enough. The water was heating up fine all summer and when they tried to turn the heating on it all started switching itself off. The filter was full of sludgy rust even though the heating had been off for months and the filter had been cleaned just before switching off. I’ve been told the filter should not be an issue after it’s all sealed.
The heating engineer said that there’s too much sludge in the system which is what’s causing the water pressure drop and it’s possible some has found it’s way into the boiler.
Earlier in the year they replaced a pump because it had gotten in there. They aren’t cheap but the guy who runs it initially suggested changing the radiators. Which from what I now know would only be a temporary fix. The guy who came the other day said you shouldn’t need to do that no matter how old they are if you change it to a sealed system and do a powerflush.
I feel the same way Sweetie! I now know all about gravity systems vs sealed and all about the way rust builds up etc. It’s many hours of my life of having this explained that I will never get back!
By the way my sympathies on your own painful experiences. It’s like a never ending saga.
Forget the sealed system for a mo, unless you have money to burn…
Open vent systems have a natural amount of water loss due to venting. The system is gradually topped up through the small tank in the loft. As the tank level drops, it’s topped up by new oxygenated water, which causes the internal corrosion. If an inhibitor is added, it slows this process considerably.
I’d go with a flush, inhibitor and a magnaclean from what you’ve said.
