Flushing a radiator from the top?

[AkiraDIY]

Long story short, I took a rad off the wall and flushed out a ton of sludge. Rehung and it's improved considerably but not completely. The back panel is now hot all along the bottom but the front panel is still cold along most of the bottom. Doesn't start getting hot until a third of the way up at the worst part.

The radiator is much heavier than I imagined (around 50kg empty) so to avoid breaking my back, fingers, and toes, I was wondering if it would be possible to flush from the top? I.e. remove the bleed valve, the blanking cap on the other side, connect water and drain hoses, and flush without removing the rad. Or will the flow rate not be enough to force out sludge from the top?
(the drain hose would be about 8m long unless I fire it out the adjacent window, which I'd rather not for obvious reasons)

 

[just pumps]

Flushing water through from the top will reduce the flow rate to next to nothing. Did you knock the bottom of the rad as you were flushing as this does help with the cleaning through.

 

[AkiraDIY]

what if I connect the water to the top and drain from the bottom, any difference?

Mainly because I can get a hose onto the bottom TRV side but the lockshield side doesn't have enough movement in the pipes to connect a fitting and hose. Maybe I'll look for a smaller fitting and see if I can attach something on the lock shield side.

I rocked the rad side to side and hit it relatively hard along the bottom with a rubber mallet while flushing. I think I cleared out one panel and the other just remained stubbornly blocked.

 

[JohnD]

Did you use a sludge-loosening chemical first?

Can you get hold of an SDS+ drill?

 

[AkiraDIY]

I didn't use any chemical, I was only flushing one rad, not the whole system. I didn't want to use chemical cleaner as I was worried that it would block the microbore or damage the boiler.

I'll either try to get a SDS drill and give the radiator a proper beating or flush it somewhere with enough space where I can flip it round and stuff. I flushed it in the bathroom first time (I'm top floor and it was too heavy to haul it down myself) and it was too narrow to flip.

 

[DP]

I didn't use any chemical, I was only flushing one rad, not the whole system. I didn't want to use chemical cleaner as I was worried that it would block the microbore or damage the boiler.

I'll either try to get a SDS drill and give the radiator a proper beating or flush it somewhere with enough space where I can flip it round and stuff. I flushed it in the bathroom first time (I'm top floor and it was too heavy to haul it down myself) and it was too narrow to flip.

A rubber hammer will work equally well.
Base of the radiator being cold means nothing on its own. Does not mean the radiator is bunged up. You might have meagre flow to that radiator Despite the rad being clear.

You have to understand radiator operation when hot water is pumped into it

Water going into the radiator rises to the top bar and displaces cold water from it ( hot liquids and air naturally rises and cold sinks)
Hot water then accumulates in the vertical channels. Mean while water coming in will displace cold water which flows out.

After a period of several minutes there should be a temperature gradient between inflow and outflow water temperature. For modern boilers it can be 20 degrees and for cast iron it was often 11. If the radiator is getting it’s designated water flow, it will be hot at the inlet and specific degree amount cooler at the outflow but the radiator will be hot uniformly.

If the base of the vertical channels is covered with sludge, Center of the radiator will be cold yet outer ribs and top roasting hot


Take the radiator off, take it to the garden and using hose to flush the dislodge effected by use of rubber hammer will give you top results.

Other option is to fit a Megnaclean ( not just any filter) to the return at the boiler. Over time the radiator will clear if the filter is regularly cleaned. Have done this with positive results.

Other option is use Sentinel x800 BUT follow makers advice to a tee else results will not be pleasant. Again, have used this chemical with great results.

 

[AkiraDIY]

I'll get a mate round to help with lifting it and give it another flush this weekend, make sure to tip it upside down as well.

 

[gas112]

I'll get a mate round to help with lifting it and give it another flush this weekend, make sure to tip it upside down as well.

empty it then half fill it then both of you give it a good shake slushing the water back and forth empty it then flush it through from both sides empty it half fill again and good shake empty and repeat till water clear

 

[Madrab]

my approach is take all the bungs out, stand it on it's end and then use a hose and flush from top to bottom and do each of the 4 ends till it runs clear out the bottom, sit it on a piece of wood so the bottom outlet is raised and it empties quickly, gravity is your friend here.

 

[AkiraDIY]

Gravity is a double edged sword in this case. I flushed it in my bathroom as I was not getting a 1600mm 50kg rad down 4 flights of stairs without damaging either the stairs, the rad, myself, or most likely all of the above. I severely underestimated how heavy it would be, not even sure I'd want to try with 2 people.
I'll get a longer drain hose and flush just outside my bathroom so I have the space to flip the rad around while flushing. That and some extra patience when flushing should be enough

 

[just pumps]

I think it is a 7 person job
Two people trained to lift the rad with backs straight and knees bent and to lift and lower the rad in unison when sloshing the water around the rad.
One person to control the hose pipe to ensure maximum water flow at all times.
One licenced person to operate the rubber mallet.
One `elf n safety person to operate the clipboard plus checking a PPE is worn at all times.
One first aider to treat any muscle strain and wet feet.
RSPCA officer to make sure that no animals get wet or stained with black sludge.

Did I forget anyone?

 

[pcaouolte]

Did I forget anyone?

Environmental Health Officer to worry about the long term effects of black sludge on Polar Bears after it has migrated through the groundwater?

 

[gas112]

1600 rad thats a baby we used to take out whilst still full and flush 2.5 metre by 700mm doubles now they were bloody heavy . But dont blame you with all those stairs

 

[mcprinter]

A rubber hammer will work equally well.
Base of the radiator being cold means nothing on its own. Does not mean the radiator is bunged up. You might have meagre flow to that radiator Despite the rad being clear.

You have to understand radiator operation when hot water is pumped into it

Water going into the radiator rises to the top bar and displaces cold water from it ( hot liquids and air naturally rises and cold sinks)
Hot water then accumulates in the vertical channels. Mean while water coming in will displace cold water which flows out.

After a period of several minutes there should be a temperature gradient between inflow and outflow water temperature. For modern boilers it can be 20 degrees and for cast iron it was often 11. If the radiator is getting it’s designated water flow, it will be hot at the inlet and specific degree amount cooler at the outflow but the radiator will be hot uniformly.

If the base of the vertical channels is covered with sludge, Center of the radiator will be cold yet outer ribs and top roasting hot


Take the radiator off, take it to the garden and using hose to flush the dislodge effected by use of rubber hammer will give you top results.

Other option is to fit a Megnaclean ( not just any filter) to the return at the boiler. Over time the radiator will clear if the filter is regularly cleaned. Have done this with positive results.

Other option is use Sentinel x800 BUT follow makers advice to a tee else results will not be pleasant. Again, have used this chemical with great results.

DIY and have done all my rads in the last year.
Outside and banged with a rubber mallet.

Fitted a Magnaclene on the Boiler return
Put X400 in for a few Weeks. Very dark when drained.
I believe X800 is very aggressive and can cause problems if not used properly. Probably more suited to a pro than DIY?

 

[AkiraDIY]

chemical cleaner is a last resort for me. Don't want to risk pinholes or fouling the boiler at the moment.

Magnacleans I've had poor experiences with, generally frequent leaking from the main lid. Usually happens after a service and the system gets hot but also had a brand new one leak immediately and need to be returned. Currently using a spirotech style one from valliant. Seems to do the job and I've had no problems whatsoever with it