Is it worth cleaning our an old radiator?

seatbeltnoob

hello got a old rad - not sure how old it is, I presume very old because the rad itself used union valves.

The heat output is quite poor. it uses lockshield on both sides and I've fulled opend them (anti clockwise both of them). and the heat output is really patchy. I presume it's fully gunked up.

The bootm gets really got quickly, the top heats up slowly. The top from the return side doesnt even get hot - its just warm. The top on the flow side is nice and hot - after a long time.

A replacement is around £50. I was wondering whether it worth disconnecting the rad and giving it a good clean using the shake and hose method. Or will I be wasting my time?

It's a small rad 600 x 600. So not big.

The other issue is the bleed valve is messed up - it broke off. Does that pretty much rule out cleasning it because it will have trapped air? or does the trapped air equalise with other raditors on the same floor, so I can always get the air out elsewhere. 

Grenage

Cold at top is often air that needs bleeding.  There's no harm in rinsing it through in the garden with a hose.  I normally do that when I decorate a room.

molerat

If the bleed valve is broken air will be trapped, air will not travel downwards and escape into the next radiator along.

seatbeltnoob

it does get hot at the top, but slowly. I think it's more down to it being filled with sludge.

FreeBear

First, you should not have opened up both valves fully - You have now messed up the balance of the entire heating system. In addition, the water will just go in one end and out the other without properly circulating inside the radiator. Turn one of the valves down so that you get a 10-12°C difference between inlet and outlet (maybe as high as 20°C if the water temperature is 70°C).

With some radiators, the bleed nipple is set in to a blanking plug at the side of the radiator - If this is the case, places like Screwfix - https://www.screwfix.com/p/radiator-vent-blanking-plug-nickel-2-pack/40972

Taking the radiator outside and flushing it with a hose will get rid of a lot of the sludge sitting in the bottom. Just plug both ends before you lift the radiator off the wall otherwise you will get black gunk everywhere (and trust me, it stains everything). Once back on, refill the system and add corrosion inhibitor at the same time, then balance the whole system.

If you do decide to change the radiator, it may pay to fit a larger one or just go for a type 21 if the old one is a type 11.

seatbeltnoob

FreeBear said:

First, you should not have opened up both valves fully - You have now messed up the balance of the entire heating system. In addition, the water will just go in one end and out the other without properly circulating inside the radiator. Turn one of the valves down so that you get a 10-12°C difference between inlet and outlet (maybe as high as 20°C if the water temperature is 70°C).

With some radiators, the bleed nipple is set in to a blanking plug at the side of the radiator - If this is the case, places like Screwfix - https://www.screwfix.com/p/radiator-vent-blanking-plug-nickel-2-pack/40972

Taking the radiator outside and flushing it with a hose will get rid of a lot of the sludge sitting in the bottom. Just plug both ends before you lift the radiator off the wall otherwise you will get black gunk everywhere (and trust me, it stains everything). Once back on, refill the system and add corrosion inhibitor at the same time, then balance the whole system.

If you do decide to change the radiator, it may pay to fit a larger one or just go for a type 21 if the old one is a type 11.

balancing is not rocket science. It's just a matter of make sure all the rads warm up the same time. Turn the heating on and walk around the house feeling all the rads. If one is too hot and another is not warming up at all. You just reduce the flow on the hottest one, and increase the flow on the slowest one.

I had to open it up all the way to make sure the radiator is indeed sludged up.

I have decided to just replace the entire rad bacause the broken off bleed nipple is problemaic.

ThisIsWeird

Good move - you cannot have a fully functioning rad that cannot be bled!
And, if this was caused by sludge, the classic symptom would be a cold central bottom - ooh-er missus - as this is where sludge collects. You didn't.
So, given the low cost and broken bleeder, you've done the right thing.
Good point above, tho' - always go 'large' whenever you replace a rad, as this will mean it'll output with a cooler water supply = more efficiency.

seatbeltnoob

ThisIsWeird said:

Good move - you cannot have a fully functioning rad that cannot be bled!
And, if this was caused by sludge, the classic symptom would be a cold central bottom - ooh-er missus - as this is where sludge collects. You didn't.
So, given the low cost and broken bleeder, you've done the right thing.
Good point above, tho' - always go 'large' whenever you replace a rad, as this will mean it'll output with a cooler water supply = more efficiency.

Unfortunatately the rads in this property are all tiny. Looks like they just speecced the rads to be just big enough to meet the rooms BTU needs. . So I dont want to drastically change the central heating setup, (low flow temp + more surface area method) I'll just do like for like until a completely new central heating system is needed. The other 5 rooms dont have massive rads so I can't just have a massive one for 1 room alone.

ThisIsWeird

Fair do's.
It's a general recommendation, that's all - taking the opportunity to evolve your system when an obvious opportunity comes along. But, if you don't anticipate swapping others in the foreseeable, then little point (unless it's the 'main' rads in the living area).
Happy new rad
Try and note the position of the lockshield valve so you can reopen it to a similar level with the new rad.

ArbitraryRandom

seatbeltnoob said:

FreeBear said:

First, you should not have opened up both valves fully - You have now messed up the balance of the entire heating system. In addition, the water will just go in one end and out the other without properly circulating inside the radiator. Turn one of the valves down so that you get a 10-12°C difference between inlet and outlet (maybe as high as 20°C if the water temperature is 70°C).

With some radiators, the bleed nipple is set in to a blanking plug at the side of the radiator - If this is the case, places like Screwfix - https://www.screwfix.com/p/radiator-vent-blanking-plug-nickel-2-pack/40972

Taking the radiator outside and flushing it with a hose will get rid of a lot of the sludge sitting in the bottom. Just plug both ends before you lift the radiator off the wall otherwise you will get black gunk everywhere (and trust me, it stains everything). Once back on, refill the system and add corrosion inhibitor at the same time, then balance the whole system.

If you do decide to change the radiator, it may pay to fit a larger one or just go for a type 21 if the old one is a type 11.

balancing is not rocket science. 

Doing it properly, so as to be most efficient with a low boiler flow temp, takes blooming forever though! 

One job I'm glad that doesn't need doing every year  

seatbeltnoob

job done. radiator installs are always messy and take longer than you expect. I chnage radiator valves before with upgrade TRVs, this time changed the entire radiator. The valves seals always leaked for me at first. You seem to need an ungodly amount of ptfe to seal the tails to the rad.

But now that it's fitted I'm happy, job done and the heat output on the replaced rad is excellent.

I would have had a go at just cleaning out the rad - but the clincher for me was the broken bleed valve.