Draining CH which might / probably already contains anti-corrosion chemical

[Clive Long,UK]

Hi

I successfully replaced a seized CH pump (based on the help I received in this group). The CH now fair old blasts.

The (2-year !!) "old" pump was blocked with what I can only describes as "slivers" of rust. Now I want to drain the system to try and avoid the problem recurring in a couple of years. I have bought X100 and X400 anti-sludge and inhibitor and am confident with the flushing and filling process through the header tank.

However, when I put in the chemical (100? 400? - read instructions!) that should get the sludge into suspension before I flush the system (rads will have to stay on walls), will the existing inhibitor in the system's water supply react "against" the sludge remover? Will I have to drain the whole system first before I put in the 100? 400?

Thanks

Clive

[Andy Hall]

If it was that bad, you might want to consider my method of cleaning involving removing radiators and flushing them outside the house with a mains hose or a pressure washer.

If there are loose bits of solid material in the system, they will almost certainly not go into solution in a desludging chemical.

Once you have removed the worst, then use the chemical followed by thorough flushing. In the circumstances, I would also put in a strainer on the return connection to the boiler.

In general with treatment chemicals always flush thoroughly before the next is used.

Obviously at the end, add some inhibitor

.andy

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[Kalico]

Can you buy these strainers to use with normal 22mm pipe?

[fred]

In article , Kalico writes

Yup, see:

have one of these fitted (22mm comp) but thought the filter mesh wasn't held tight enough in the body to get full straining. A cut down rubber washer under the _cap_ made it more secure. Be aware:

1. It may restrict flow a little, particularly if you have crud flowing round the system. If I was doing it again, I would prob use a larger one, say 1 1/2" with reducing fittings either end to mate with 22mm.
2. You'll want to make it easy to check for blockage, fit a full flow 22mm ball valve at either end to isolate it.

[Andy Hall]

Yes you can. Most heating suppliers carry them or you can buy on line from BES.

I used a 28mm size on the return because I was combining two 22mm returns from different parts of the house. You can also get them with BSP female taps and add your own couplers to copper.

I also fitted lever ball valves as isolation at various parts of my system to allow for selective draining and also when flushing to direct water where I wanted it.

.andy

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[Christian McArdle]

You don't have to, but I would anyway. There's no point in wasting good chemicals when a few clean water flushes will get much of it out before they are introduced. Think of it as emptying scraps off the plate into the bin before using the Fairy liquid.

Obviously, just using chemicals won't get rid of all the crud. If it is badly affected, a proper power flush (DIY, not being fleeced by BG) or pressure washer manual flush would be called for.

Christian.

[Clive Long,UK]

As I feared, this is turning into a bigger job then I hoped

This "strainer". If there is much solid material floating around in suspension, won't it just clog up eventually? Much better there, than the pump I guess. But how do I clean this "strainer"?

Clive

[Andy Hall]

Well, the point is that you should get as much of the crud out of the system by thoroughly cleaning first. As I mentioned, because you are getting quite large flakes, it is probably breaking off from inside the radiators. Hence my suggestion of taking them off and outside and pressure washing them, tapping with a mallet as you go.. THat will get rid of most of the loose material. I suspect that if you don't do this, you will have a recurring problem which over a period of time will become a real time waster. It should be possible to clean all the radiators in the house in half a day.

Regarding the strainer, the best way is to have an isolating valve (lever ball valve) each side of it. Then you simply stop the system, isolate the strainer and the top undoes with a spanner. Inside there is a cylindrical stainless steel mesh. You simply take that and rinse it.

.andy

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