How can I find this out for sure before actually hiring one? The instructions of the HSS one were vague at best about this matter. I doubt the hire shop will really know how to use it.
I haven't looked yet but I would almost bet that the pump in my combi boiler will be fairly inaccessable. Indeed some flushing guides advise isolating the boiler which would not be possible if connected to the pump?
I'd like to do it right, but using the power flush seems confusing to me (not the principle but the practicality). I can forsee a situation where I hire the thing and cannot use it.
Yes, they were the instructions I was referring to! There it says it can be connected across the pump with it removed or across the radiator so I guess the latter would be better for me.
Reading the instructions today they don't seem quite as confusing ;-) I wish they described the procedure for a sealed system though.
Can anyone explain how to get inhibitor (X100) in to a sealed system?
Just use a cartridge gun. IIRC x100 comes with a plastic spout for radiators. What I did was to loosen the bleed valve on the highest rad in the house and catch the water in a bowl. About a litre came out of mine. Then remove the valve altogether. Put the stuff in gradually over a couple of hours and give it a helping hand with a piece of wire or something. It did all go in eventually but, as it's just a load of crystals in detergent, it tends to block the hole.
Might take a couple of days for the system to settle down afterwards. Boric acid isn't very soluble, especially in cold water, so it needs a lot of circulating before it's all dissolved and can start doing its job. During that time you're likely to get random readings on the pressure gauge. Yes, it's a lot of money to pay for a cheap chemical but we all like to put our faith in a named product
If you've got a bathroom towel rail with the valve on top (ie pointing skyward), the easiest way is to release the pressure in the system by draining off at any suitable point (even the towel rail bleed valve if need be, and then unscrew the valve completely. Drain off enough volume to allow the volume of inhibitor to be added, and just pour the stuff in. (You can just as easily use the conventional stuff as the more expensive cartridge/concentrate.)
You could begin by isolating one radiator and emptying it into containers. Keep in mind that the water is an indellible dye.
If there is a lot of sludge then cleaning should happen. You could do this by removing radiators one at a time and flushing them outside. While a radiator is removed, Flush some clean water through by connecting up and running the filling loop. This means that sludge in the pipes will be flushed out rather than around the system.
You could find out the make and model available from HSS and contact the manufacturer for detailed instructions if you choose that approach.
Thanks again Andy for your advice. I have only taken one radiator off so far and there was only a small amount of sludge, most of the water was clear. I was tending towards the power flush option because some of the rooms have nice carpets and SWMBO would have a fit if anything got spilled on them.
I wonder if I could just use the filling loop without removing all the radiators?
There only seems to be HSS logos on the instructions.
I made one of these to be able to refill my secondary circuit (used for the workshop and supplied with heat via a plate heat exchanger). This circuit is substantially dosed with Alphi-11 inhibitor, containing antifreeze, which is quite expensive, so I wanted to be able to keep the liquid if it's necessary to partly drain down and put it back afterwards.
The recipe was the bog standard large capacity Hozelock sprayer from wherever. The aluminium tube forming the lance will fit well into an 8mm brass compression fitting. I used a 8x8mm coupler From there I adapted upwards using a short piece of 8mm copper tube to a 8x15mm adaptor with male tail with that going into a 15mm x 3/4 BSP male fitting - i.e. something onto which the filling loop will go.
I've found that I can get the pressure up to about 1.5 bar with this. On refilling, I add a little more fresh Alphi-11 to the mix and finally top up with mains water to 2 bar. This avoids dilution.
I agree, though, the last few sprayer tank fulls beyond 1 bar are hard work.
You can protect for this quite well with some care. I used two (new) cat litter trays from the supermarket, one under each radiator tail. This gives plenty of catch capacity. A thick PVC sheet went down first followed by absorbent paper and I had some disposable mop-up towel and a bucket on hand.
I turned off the radiator valves and then carefully undid one union part way. Then opening the bleed valve allows the water out in a controlled way. Finally Undo the other union and carefully tip the radiator towards one end to drain most of the rest. Take small sandwich bags and fit them over the tails on the radiators securing with a thick rubber band. You are now safe to remove radiator to outside.
You need to use it anyway. I thought about doing this to flush the radiators at each radiator position. The trouble is that you would need to flush a fair bit through the radiator itself to clear the debris. I found that with taking them outside, I could flush much more effectively.
If you meant using the mains pressure to flush via one radiator at a time to a drain c*ck, that might work, but I don't think as effective. Also, you would probably need to fit isolating valves to the boiler to make sure that you can't either have a short path to drain through it or that you flush debris through it from the radiators.
While you're at it, fitting a strainer with stainless steel mesh on the return to the boiler is a good idea.
That's a pain. I wonder if there's anywhere else that rents them out.
That was the kind of thing I was thinking about. However I'm not sure I could easily fit isolating values. There is only one place I can get to the pipes without ripping up floors etc and the pipes are _very_ close together. I doubt I could squeeze anything in let alone cut the pipes.
As above - not sure how I could achieve this.
I'll need to do this anyway. HSS have closed my local branch (even though it's still listed).
Not unless you can guarantee getting every last scrap of debris out of the system: a small amount of crud is enough to block the strainer up and stop circulation through the system.
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