DIY Flushing

[sm1thson]

Ive decided to flush my CH system (sealed combi worcester 24CDI). we wont go into the the pros and cons on DIY vs power flush here as its been discussed before (here) but i want to weigh up my method over other DIY methods.

i have had a couple of radiators off recently for decorating (and the kitchen one is still off) the sludge wasnt that bad, but i reckon its due doing (system 5years old). i was originally just going to do it via the fill loop and drain, i know it would be best to put ball valves on the flow and return but Ive never done anything like that. then i had an idea- I will connect hoses to the radiator valves (as the radiator is allready off) -this should give lots of flow! an other advantage of this is i can do it all from the kitchen so if something gets wet its not a problem, where as the boiler is upstairs.

-i would expect the above to give (almost) as good flow as ball valves? -any critasism on the above compared to the DIY method decribed here

afew more questions:

from what i have read i should:

-close valves to the boiler to stop my flush washing crap into the heatexchange -right or wrong?

-monitor the pressure? -but the boiler pressure wont read if i shut off valves, and its upstais so no good! i will put a guage on the hosepipe connection (if this is necerssary), but as i will be doing this from downstairs i would expect the pressure to read higher than upstairs? (1.5psi per metre i think??) -so what should i pressurise to when flushing? (-state if you are quoting upstairs or downstairs pressure)-how do i build up pressure-just block the outlet hose watch the pressure rise then release??

i will run a chemical desludger (and inhabiter after) but they generally recomend to leave in the system for a week, or run the sytem for 8 hours etc. but its summer and i really dont want my radiators on! -what can i do? -just run the CH when Im out?

-other posts mentioned particle filters, -should i change these after?

 

[bster]

you wont need to build up pressure if its on the mains (use a double check valve), hit the radiators with a rubber mallet when individualy flushing each rad and COMPLETLY drain the sytsem once finished.

I would add a chemical 2 weeks before you flush and drain out hot.



dont forget inhibitor and if you wont future protection put a magnetic filter in.

 

[bab]

If u only close one of the isolation valves on ya boiler the gauge will still register but the flow wont pass through dirty. as 4 a rubber mallet thats a new one on me. It must be my lack of experience.

 

[bster]

bab - i've flushed rads in a customers garden until its running clear, hit it with a hammer and it'll run dirty again. Because of this when we do a proper powerflush we hit the rads (esp the bottom) to dislodge the sh*t.

You can actually buy an 'agitator' that fits onto a cordless drill for this very purpose - i'm not making this up!
(i think it is marketed by the same people\distrubuters as the 'MagnaClean' magnetic filter).


just found a link http://www.kamco.co.uk/Vibraclean.htm

 

[corgiman]

bab - i've flushed rads in a customers garden until its running clear, hit it with a hammer and it'll run dirty again. Because of this when we do a proper powerflush we hit the rads (esp the bottom) to dislodge the sh*t.

You can actually buy an 'agitator' that fits onto a cordless drill for this very purpose - i'm not making this up!
(i think it is marketed by the same people\distrubuters as the 'MagnaClean' magnetic filter).


just found a link http://www.kamco.co.uk/Vibraclean.htm

cleans rads and looks like it would keep a hen night happy to

 

[bster]

dirrrty and clean at the same time then.

 

[sm1thson]

looks like it should be good then. do i need to have the heating on for the 2 weeks the desludger is in the system? (i will flush when hot)

 

[sm1thson]

bster you said to drain hot, which sounded like a good idea, but the FAQ say "5.1) DO NOT let water into a hot boiler, let it cool first." -so do i drain it hot then wait (how long?) then get flushing? -or what?

-also i am still under the impresion i need to monitor the water pressure during this but my above questions on pressure havent been answered? -how much pressure? (when measured upstairs and downstairs)

 

[ChrisR]

If you've been running the jizzm round for two weeks you've done the dissolving, flushing hot wouldn't make much if any difference.

If one boiler valve is shut, there won't be any cold water going through the boiler.

If you connect via rad valves you don't get very good flow. TRV's are really restrictive, often they have a tiny hole even full open. With the resistance of the hose as well, you will prob find it's well worth squashing some air in the system. Tell by colour of water.

Pressure diff between up and downstairs will only be say 2.5 metres = 0.25 bar.

Banging rads helps a lot if they're sludgy. Wouldn't be surprised if yours aren't bad at all after 5 years in a closed system.

Cleaning the secondary heat exchanger would be a good idea. You have to take it out cos the diverter stops you flushing it, from a rad.
If you don't want to take it out, turn the boiler on with gas off, and turn the hot tap on and off. That will make the pump push water round the boiler, then to the ch system and repeat, to remove the chems from the boiler. With pump off you can flush the main h/e backwards but not the secondary one.

 

[sm1thson]

Thanks thats the kindof post Ive been waiting for!

If you've been running the jizzm round for two weeks you've done the dissolving, flushing hot wouldn't make much if any difference.

sounds good. I guess I will need to turn the heating on for a couple of weeks then? (well for a couple of times a day at least)

If you connect via rad valves you don't get very good flow. TRV's are really restrictive, often they have a tiny hole even full open. With the resistance of the hose as well, you will prob find it's well worth squashing some air in the system. Tell by colour of water..

Ok will try building up some pressure.

Pressure diff between up and downstairs will only be say 2.5 metres = 0.25 bar..

that about what I make it (but I work in psi for some reason)

Banging rads helps a lot if they're sludgy. Wouldn't be surprised if yours aren't bad at all after 5 years in a closed system.

will bang them. There not bad, I had a couple off for decorating sludge wasn’t much. Because I needed to top up I figured should put some new inhibitor in and figured it would be best to clean it all first –prevention is cheaper than the cure and all that.

Cleaning the secondary heat exchanger would be a good idea. You have to take it out cos the diverter stops you flushing it, from a rad.
If you don't want to take it out, turn the boiler on with gas off, and turn the hot tap on and off. That will make the pump push water round the boiler, then to the ch system and repeat, to remove the chems from the boiler. With pump off you can flush the main h/e backwards but not the secondary one.

Hmm will have a look and a think, from what I have read on here the 24cdi is a pain to work on and leaks afterwards! –any advise for preventing leaks when I put the heat exchange back on –just ptfe tape or what?

 

[Paul Barker]

If you use Ferroquest you can have it done in a day.

 

[Agile]

Yes, I would recommend Sentinel X800.

Tony

 

[htgeng]

Im a superfloc man myself I did a boiler replacement last week and used the rubber mallet on the rads. It did seem to make a difference even just running the cleaning solution through for a few hours. The customer said they had never felt the rads so hot before. You could smell the heat

I've used Fernox DS-40 before on really badly sludged systems, but it takes a lot of legwork when you have to drain down and bleed rads so many times! Thats when you need a slave, oops i mean apprentice