Do my radiators need a powerflush?

MrDomMan

I'm really not sure if they need a powerflush or not or if what i'm seeing is normal.

But there appears to be a quite a big temperature difference between the top of the radiator and the bottom of the radiator,  now I wouldn't say the bottom is cold as such so i'm not sure what i'm seeing is normal or not.


I made a video to show the the issue, if anyone could advise and tell me what I should be seeing as normal. I checked all rads over the house and they all seem to give the same like readings so I can't tell.

I have emailed someone about a powerflush but have not received any response back from them.

My vid: https://youtu.be/0ufs_4oKrXU

MrDomMan

Just worth pointing out, that the I've read there should be a temp difference between inlet pipe and return pipe of 12c drop this is more into relation to balancing the system than sludge build up but in the video you can see there is barely any difference between the two temps either, so not sure if that is some kind of contributing factor.

Ebe_Scrooge

Well, radiators that are hot at the top and cooler at the bottom is a classic sign of sludge.  I must say it's somewhat unusual for every rad to have the same issue though - usually you'll find the sludge tends to collect in just a couple mostly.  And the inlet and return pipes being the same temperature sounds odd as well.

You could potentially do a bit of investigation yourself.  If you turn off both valves to one of the rads, they're usually pretty easy to remove.  Have a couple of washing-up bowls and plenty of old towels to hand to catch the water that'll come out, and unscrew the rad.  Take it outside and flush it through with a garden hose - if it's full of sludge, you'll be able to see it coming out.

When you're closing the lockshield valve, count how many turns it takes to close it.  When you refit the rad, make sure you re-open it to the same position it was originally in.  That'll mean the balancing will be the same as it was.

That will at least give you a clue as to whether the whole system is full of sludge, or whether it's something else.

The other possibility - and one that's probably a bit easier to try - is to look at the pump.  They've normally got a speed setting, usually low, medium and high.  It might be worth increasing the speed (if it's not already set to its highest), see if that helps at all.

Sorry, I'm no plumbing expert, but there's a couple of things that are reasonably easy to try, might at least give you some further clues

NannaH

You can do a chemical flush yourself.   Add the cleaner, clean out your magnavlean if you have one, leave for a week,  drain the system,  refill with water and drain again then refill and add inhibitor.  Oh and clean the magnet again - you won’t believe the amount of crap it will pick up during that week.  Last job is to bleed rads. 

If you have a hosepipe and jubilee clip it’s easy to drain down. 
My husband charges £150, including chemicals for said service, so diy will cost you £30 for a bottle of system cleaner plus a bottle of inhibitor. 

NannaH

A power flush is £400-£500.  

diystarter7

Hi OP

Is it just the one rad??

If so, you have a TVR etc as pin could be stuck.  I had the same problem 20-25 years ago on a relatively new cH heating sytem took of the ruddy rad, flushed it etc but still cool at the bottom. Then a friend came to ours I told him he took off the TVR top  and moved the pin around a bit then closed fully and opened it several times and never had that problem again the rad was pipping hot all over.   

NB: Be careful with the pin as it did pop out but he managed to stick it back in asap and never had another problem with it.

Thanks

plumb1_2

You can’t really do a powerflush by just adding a cleaner to the system .
I used to use a kamco dual flow, forward and reverse action, with dual filters linked in.
Drain down, remove rad and connect to 15mm pipes, if 10mm pipes remove pump head and connect, failing that cut into 22 pipes.
Give it 30 minutes flush with clean water, then dump it.
Next add cleaner, flush whole system, then close all rads and do each one individual use a rad hammer to loosen sludge. And keep altering flow.
Next dump water again, fill with clean water and add naturalising crystals, treat whole system.
Check PH level of water, should be the same as incoming water main.
Next dump water again, disconnect machine and reinstate system 
Next inject inhibitor through air vent.

Usually 5/6 hrs work. People/engineers who just put som F3 in and give a quick 30 minute go with the heating on, are having you on. It’s ok if was a brand new full install 

Happly I don’t do it anymore, gave all my equipment to younger plumb1 a couple of year’s ago.

Ebe_Scrooge

diystarter7 said:

Hi OP

Is it just the one rad??

OP said it's all rads:

MrDomMan said:

I checked all rads over the house and they all seem to give the same like readings so I can't tell.

I agree, a stuck TRV pin is common, especially if it's the first time the heating's been on after summer.  But unusual for all of them to be stuck.  No harm in checking though, I suppose.

diystarter7

Hi

To avoid stuck pins just in case that is the problem which I now doubt as its all rads - do not fully close TVR's unless removing a rad etc. This can often avoid sticking pin.

I think it may be a balancing thing with a possible stuck pin here and there.

Thanks

plumb1_2

The pin is either stuck or not,  so if stuck why is the rad getting warm.

Mutton_Geoff

The input cannot be cooler than the top of the rad, so try measuring again putting your thermometer closer to the rad. Those cheap handheld things are not very accurate with chrome or white paint, best to paint a bit of non reflective black or stick a bit of matt black tape on the rad in the places you want to measure.

Heat rises so the centre bottom is bound to be cooler than the other parts. Try balancing the rads. The flow side will be the one that gets hotter. Open fully and balance with the lockshield (return) side valve.