Has anyone been Powerflushed (central heating - nothing medical!). It was recently recommended by my "friendly" service engineer but I was staggered by the cost ~£550. This seems a lot to pay for one man and a pump for the day? Got another quote for around £400 but that still seems pricey.
Anyone had it done/know if it is worth it/recommend an alternative.
Thanks
JohnW
The alternative, which is *much* cheaper - and probably better - but more work, is to remove all the radiators, take them outside, and blast the crud out with a hosepipe. And wash out the pipes to each rad while it is removed.
I bet he was friendly. This is money for old rope. He is not likely to take the whole day over it.
There are a few alternatives.
a) Rent the machine and chemicals and do the job yourself for less than half this price.
b) Desludge and clean the system by draining and removing the radiators and flushing them outside. Not too much fun in this weather. I've posted a detailed procedure for this in the past and you can find it through Google Groups.
c) If sludging is very light - e.g. no cool spots in the centre bottoms of radiators and all working OK, then you can try a chemical flushing agent such as Fernox or Sentinel. You add this stuff and run the system hot for the recommended period - few hours to a few days. This is not satisfactory for badly sludged systems though and worth using after b) above.
With any, do bear in mind that sludge is basically iron salts and these make an indellible dye with great affinity for decorations and carpets so take appropriate precautions.
In all cases make sure that an inhibitor is added afterwards and concentration maintained. This way, you will avoid the problem in the future.
Thanks for that useful info Andy.
Before I try this, a quick question.
Can I just add the flushing agent to the system as it is now or should I drain, fill and then add the flushing agent?
Thanks Bob
Definitely flush and drain before adding flushing agent - i.e. get as much stuff out of the system as you can.
But before doing this, do check the radiators for cold spots and also when you drain, let the sediment settle and see if there is a lot of solid material. If there is, then you really need to do a) or b)
I recently tried to add inhibitor to my sealed-combi system. With the system drained down, I was still unable to get the stuff in (via one of the rads) without it spilling out all over the place, even though the rad itself was empty. Is there some special kind of funnel available which fits properly onto the rad to prevent this?
KotF
You can get inhibitor in a tube like mastic. Just turn off the rad, remove the bleed screw, screw the plastic nozzle from the tube into bleed screw hole, turn on the rad and squirt the stuff in. Only takes a few seconds.
Rgds
Andy R
This does work well. However, it is better to drain the individual radiator to do it rather than doing what the manufacturer suggests and injecting against the pressure. The little nozzle doesn't make a particularly good seal and water will tend to squirt past it.
The sludge itself IMHO does not cause corrosion however there may be reasons why the sludge formed and these need to addressed whatever the method that is used to remove the sludge.
Surely the radiators are a minor part of the problem - small pipes with dips or low spots will cause big problems.
It really depends on the pipe sizes and how mobile the sludge material is. Remember that it is the corrosion of the steel in the radiators which is most of the crud, plus assorted copper swarf left by lazy installers. This is responsible for the classical cold spot at the bottom centre when there is bad silting.
With small pipes like 8mm, there is a greater risk of blockage if much collects. On the other hand, the velocity of water through them is likely to be higher than with 15mm.
In my detailed write up of doing the radiator removal procedure, I suggested that while the radiator is removed, each valve is opened in turn and water flushed through it. If the system is sealed, then water can be introduced via the filling loop to do this, and even a loft tank open vented system will have a reasonable flow. If this is done, debris in the pipes is flushed out of the system completely, rather than being carried round the rest of the system.
It's also good practice to have a strainer fitted to the return side of the boiler to prevent debris from being carried into the heat exchanger. Having one of these is probably two orders of magnitude less expensive than replacing a heat exchanger.
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