DS-40 aftermath

[jsoap]

Hi,

Since there were cold spots at the bottom of my radiators, which are about 15years old, I decided to give the system (Potterton Profile 60 with 5 rads) a dose of DS-40.I ran the system for a few weeks and it was running well and noticably quieter than before.

However, after draining the system, adding the neutraliser, and filling & draining 3 times, things have gone a bit pear shaped.

The boiler has started kettling, and now overheats, knocking out the safety thermostat a few times a day. As well as the kettling the boiler sometimes starts to make a cyclic swooshing noise.
I removed the pump, where there was some debris, and flushed the system out until the water ran crystal clear. Although the kettling is not as bad the boiler still trips out and the FE tank is a horrible brown mess again.

One other odd symptom, is that there is an occasional small leak at the drain valve (at the first radiator). The leak, no more than a tablespoon each time, is yellow.

Any advice would be appreciated.

 

[Agile]

The first thing you did wrong was to leave it in the system for so long!

About 6 hours starting cold and then warming up is all you need.

You have to flush out through EACH radiator in turn to ensure its all got out of the system.

I add it bit by bit and check the acidity before adding any more.

Adding just DS40 often releases lime compound flakes which start moving round the system and clog up the pump and any restrictions like pump valves.

You might find that a little DS3, sulphonic acid will improve the situation as that will dissolve lime compounds but its not very soluable.

Tony

 

[jsoap]

Thanks for the reply, I hadn't thought about limescale. However the problems at the boiler appeared as soon as I added the neutraliser, rather than a progressive problem, that I would expect if it were limescale.
Also, when flushing the system (albeit too late), I did isolate each radiator in turn.

 

[DP]

Chances are you have an air lock that is causing the boiler to trip out.

Did you check the instructions to see if neutraliser was to be added to the system with chemical in, or afterwards?

If the water is yellow, chemicals are still in the system

If you drained the system down i.e. let air into the radiators to drain these as well, the header tank would have been clear.

I think the instructions say the fill and drain six or more times. You can drain the system to get clear water yet body of the rad will still hold dirty water.

 

[jsoap]

I think that there probably was an airlock, which contributed the the swooshing noise, which has now gone. The instructions did call for the nutraliser to be added after the chemical had been drained.

I drained down again, letting the HE feed running until the water was clear again. The boiler still trips out, and its clear that the water is not getting round the system quick enough. Again even though though the water was running clear, the small drip at the drain point (outlet of 1st rad), is definitely yellow.

I think that because I simply drained the system, rather than a thorough flush, there was a lot of crud in the systen that is still there. The decision I have to make, is, what to add next. Do I repeat DS-40, or go with something less agressive?

 

[franksonny]

Try a bottle of x200- boiler noise silencer - into the header tank.
Has sorted out a bad kettling situation for me in the past.
Gotta be worth a shot.

 

[HERTS P&D]

Where's John D when you need him.

I'm sure he'll be here soon.

Anyway before he arrives, I would suggest a Magna Twin Tech, which will help remove debris from your system.

Andy

 

[ChrisR]

I drained down again, letting the HE feed running until the water was clear again.

That is NOT how you clean the stuff out of the system. You need two full diameter flushing points. I put the mains in one from the garden tap, and the other to drain. Flush one rad at a time, then reverse the flow.

Then take a small distant rad off, and see if it's clear. By leaving the chemical in there for so long, I fear you may have flakes of corrosion product sitting in there. It's pretty difficult to dissolve flakes of rust without dissolving iron/steel, so you may have to remove all the rads and flush them. Remember that rad valves are very restrictive, especially thermostatic ones.

Profiles also block with crud for a pastime, once they're old enough. It IS possible to clean them out, but these aren't boilers to play with without the right knowledge AND test kit. They can become killers. You'd have to take the front off it, which I strrongly advise you not to do. You could probably do the job from the external pipes, with lots of flow of water.

 

[Blackadder43]

I own power flushing equipment and a few of my jobs recently have been going in after someone has done a manual flush such as yours....

The problem is the chemical disturbs the crud and muck but the basic flushing doesnt get rid of it...

Its possible that some decent size lumps have now made it to the heat exchanger, hence the kettling noise and lock out.....

Hire a power flush pump, between £35 and £50 depending on area and do it properly...
Or call someone like me in and i will do it....although bucks is a bit far for me to travel...
If you want a laugh ask BG to quote you first

Good luck

If you do go down the power flush route take out the FE tank and clean it and loop the feed and expansion pipes together before you start.

 

[ChrisR]

By the way - limescale. If you do have any of that unlikely, unless you've done LOTS of water changes, DS40 would have dissolved it quite quickly. It's iron compounds which are difficult.

The mains is typically over 2 bar, more often over 3. A powerflushing pump is typically 1.3 bar, measured into a closed end - it's less with the water flowing. So if you're trying to force heavy lumps out, the mains is better. PF pumps are great for getting chemicals round, but unless you get hold of an unusual industrial one, they're quite weedy.