Flushing single rad with hose com

[joesoap13]

Hi guys, appreciate bit of advice please..
One old rad , of three, old ones, has given me problems for couple of years.
Warm top, cool bottom.
13 Rads on system
Tried everything except removing and doing it with garden hose.
History.
Last year drained it , removing both pipes at the bottom from rad, water clear as a bell ?could have drunk it, it was that clear, no sign of sludge, or colour
Left it in situ thinking pipes were maybe blocked or airlock.
Replaced Trv(, the inlet pipe to the has always been hot, to touch, but ràd at point of entry, col !) Hence replaced T R V think it,s faulty, no change.
Water coming out ok, kept topping up system high, 2 bars,, and turning T R V valve open and shut, umpteen times till water was clean, but of muck , but nowt to bother about !
New kitchen rads fitted, system drained several times to fit new rads, system clean.?
Drained again, boiler problem, water clear!

Still rad not getting hot.
This
April had new boiler and system flush by firm, assumed problem rad would be clear, surely. been properly power flushed with chemicals, and magnatec flush.
NO!!!!!
Since using CH from october,same old, pulling my hair out.
Belting it with rubber hammer, etc,
Turned all rads off except problem one, still same, turned T RV off, bled rad into bucket, from bleed valve, vice versa other valve.
Again today, thinking airlock again.!!!
Re_ filling from either side ok, so inlet, outlet pipes working ????
I have got it hotter several times ,not as hot as other old ones, or new. but just reverts to same old after a few days.


Hence, taking it off and trying to flush by hand, tomorrow,till spring, and change all three old rads, with new ones.
Any advice would be greatly appreciated. Still not convinced rad iss sludged
up, but nowt left I can think of trying till spring ?
Cannot think of what else could be problem !
The rad is ,2.5 metres long, to change it, no longer made,so means buying , 2x2metre ones and re decorating, got two of them.

 

[Justin Passing]

What sort of radiator? Pic?
If you search for radiator "2500mm" you do get a few hits. Expensive , the ones I saw.
Or you could use a 2400 and add radiator extensions - chrome m/f tubes.

If it's blocked it'll be a combination of the bottom rail, and the vertical waterways.
Start in situ with the rad empty, so it'll try more to go along the bottom, but a guess would be that crud will keep falling from the verticals, which you can't selectively get water through.

Worth a try in the garden. You'll need an assistant. Some single panel rad designs would allow you to poke or power-washer-squirt along the bottom rail, but not doubles.
Part-fill the rad and bung it. Invert it, and back, so the water tries to go up and down down the verticals. Repeat ad claritas.

You could add a descaling chemical - quite an aggressive one because you're trying to dissolve rust. Trouble is, if the rad has been corroding for long you may perforate it. Things like hydrochloric acid ("denatured" if you can get it because that will only attack metal oxides and not metal itself, in theory) or citric acid, or phosphoric acid. All are contituents of various available descaling chemicals. They would all be better warm, and still take say an hour. Doing a boiler with a boiler descaler, you'd run the boiler - ie very hot.

Look at https://www.kamco.co.uk/kamco-descaling-chemicals.html
Their scalebreaker FX (H3PO4) or HD (HCl) would do it, the latter better cold.

I'd call Kamco and discuss it.

Note that smallish quantities of hydrochloric acid are available cheaply as Spirits of Salts , which I'd dilute 1:2 of water to give 10% HCl, Add acid to water.
You're going to need a few litres.

The Kamco HD stuff may be "denatured" I don't know.

Don't omit to neutralise fully and multi-flush. Sodium hydroxide is cheapest, but viscious. Washing soda would do, sodium carbonate (Na2CO3).


You can us a very blunt drill and a block of wood, with an SDS drill, to hammer the hell out of a radiator. An inch drill run backwards won't go through. It does help a lot.

In situ, if you have sealed system you can pressurise air at the top of the rad to a couple of bar. Then open a rad valve into a bucket - the air pushes hard. If you want to you can charge up a load of rads with the same compressed air, by working out where the pipes run, which valves, etc. You get a hell of a flow rate.

 

[JohnD]

Tried everything

Including balancing?

 

[joesoap13]

What sort of radiator? Pic?
If you search for radiator "2500mm" you do get a few hits. Expensive , the ones I saw.
Or you could use a 2400 and add radiator extensions - chrome m/f tubes.

If it's blocked it'll be a combination of the bottom rail, and the vertical waterways.
Start in situ with the rad empty, so it'll try more to go along the bottom, but a guess would be that crud will keep falling from the verticals, which you can't selectively get water through.

Worth a try in the garden. You'll need an assistant. Some single panel rad designs would allow you to poke or power-washer-squirt along the bottom rail, but not doubles.
Part-fill the rad and bung it. Invert it, and back, so the water tries to go up and down down the verticals. Repeat ad claritas.

You could add a descaling chemical - quite an aggressive one because you're trying to dissolve rust. Trouble is, if the rad has been corroding for long you may perforate it. Things like hydrochloric acid ("denatured" if you can get it because that will only attack metal oxides and not metal itself, in theory) or citric acid, or phosphoric acid. All are contituents of various available descaling chemicals. They would all be better warm, and still take say an hour. Doing a boiler with a boiler descaler, you'd run the boiler - ie very hot.

Look at https://www.kamco.co.uk/kamco-descaling-chemicals.html
Their scalebreaker FX (H3PO4) or HD (HCl) would do it, the latter better cold.

I'd call Kamco and discuss it.

Note that smallish quantities of hydrochloric acid are available cheaply as Spirits of Salts , which I'd dilute 1:2 of water to give 10% HCl, Add acid to water.
You're going to need a few litres.

The Kamco HD stuff may be "denatured" I don't know.

Don't omit to neutralise fully and multi-flush. Sodium hydroxide is cheapest, but viscious. Washing soda would do, sodium carbonate (Na2CO3).


You can us a very blunt drill and a block of wood, with an SDS drill, to hammer the hell out of a radiator. An inch drill run backwards won't go through. It does help a lot.

In situ, if you have sealed system you can pressurise air at the top of the rad to a couple of bar. Then open a rad valve into a bucket - the air pushes hard. If you want to you can charge up a load of rads with the same compressed air, by working out where the pipes run, which valves, etc. You get a hell of a flow rate.

 

[joesoap13]

Thanks JP, much appreciated.
Tried 2.5 and 2.4 , no hits?
The rad s were in when I bought the house 27 years ago, only singles.
Could be stelrad, not sure?
Try to upload a pic, not too good at it!
I agree if it,s blocked it is bottom and channel, the water at the TRV is red hot,but not going in rad, just tepid up
First channel to top, and along top, cold at outlet.
Will drain rad tomorrow, run both inlet and outlet pipes, as in last post keeping pressure up , to see if either pipe is restricted, then try taking rad off, only me, so will be slight problem, solid steel and long, white carpet
All other rad s are newer, some brand new, so mixture.
The system is a mixture of copper, plastic, imperial, metric,etc
Just need to get it hot through winter then replace the 3 old ones, valves are leaking as well !
're balancing, going round Most days 're balancing them, hence leaky lockshields! Just touch them and they leak, crap.
If it,s no better then get new rad, s in spring, not cheap I know, just didn,t want to 're decorate in winter. Got spare wall paper not big job.
Won't mess with chems, just pressure hose, win or lose.
New ones If needs must, just means adjusting pipework, as well.
Should have changed them when new boiler was installed.

One leaking valve beggered lounge carpet after power flush, black after a few
days!
one thing I did think of doing, as I am solo. Is, once I confirm in/ out pipes are ok and got good flow, in situ, was pushing rod or something along bottom ,leaving the TR V on, and flushing through that , topping up as I go, and using rubber hammer for upright chanels?
doubt enough pressure though.go
2 bar versus 5 mains hose?
Thanks again.

 

[Justin Passing]

Here's one , there are others & doubles https://www.monsterplumb.co.uk/radi...op-stelrad-single-convector-300mmx2500mm-8434

Search on radiator "2500mm"

Need pic of rad & valve. Cut and past to put pic in, hit the [ ] button if it won't.
New boiler is...?

It depends where you put pressure e.g. from a mains hose and what else in the system is exposed to the pressure. A page of possibilities. You can't pressurise a whole sealed system to 5 bar.

You have a worse problem though, if the flow is so slow that the rad outlet is cold. Is the TRV jammed shut, or the lockshield spindle snapped so it's nearly shut. Both happen. New ones come jammed shut too.
Pump working? New in boiler? What happens if you shut all the other rads. If you need to keep balancing It points to a dud pump.
Unless there's an open valve near rthe pump "shorting it out".
Leaky lockshields.... If they're old which I guess they are, they'le have a spindle gland/stuffing nut which normally stops them leaking. Release to turn knob then retighten.

This crappy WIckes one does NOT have a spindle nut http://wickes.scene7.com/is/image/t...isperkins/2018-Wickes-Missing-Product-650x650

This one does - arrowed:

Clearing only the bottom channel, won't do if the verticals are blocked.

 

[joesoap13]

Hi guys, bit of an update.
Appreciate all the advice given, thanks.
Took rad off, flushed it with hose, in garde, as expected, clean,
Tested lockshied valve, good flow, let it run a while in bucket.
Tried trv side.
Just a trickle through it, got worse as I tried to clear it, even scrawled underfloor to try tapping pipe, too old to scrawl under 18 inches of floor, 30 feet from opening
SO.against my better judgement I
Decided to use garden hose.
Left drain plug open, only problem rad open, bi directional valve, I had not long put on, turned on hose fully, no water coming out of drain valve ?

Presumed inlet pipe must be blocked worse, so put rad back on, until I decided to change it, and pipe, plus other rads and a couple of leaking valves elsewhere.
Filled system up, balanced all rads again, ages, then the problem rad got as hot as others ?
Working fine now after years of problems.
Haven’t a clue why, if it was airlock, water should surely have come out of drain valve !
Not a drop. No flow through pipes or circs, zilch.
Glad it’s working, but stumped at what the problem was ?
Any ideas appreciated for peace of mind.
Ain’t expecting it to last, one day at a time !
Going to change it, and others when weather improves anyway.
Have not topped up inhibitor yet, all other rads were not drained, so I assume it should last till boiler serviced April,
First service, Worcester green star, 30 kw.
Probably let them change them then at the same time, and replace pipe to problem one , not a simple job, half plastic/copper, loop in plastic from circ, underfloor job.
Located 2400 mil rad online.
Cheers

 

[terryplumb]

What exactly did you connect hose to ,the TRV ? What was your intention when connecting hose to garden tap ?

 

[joesoap13]

I used a bit of copper pipe ,5inches, approx, with olive and nut from trv, fixed that to Trv, then hose onto pipe with jubilee clip.
Trv open, then tap on full, 5 bar approx !
Thought if there was a blockage, it would blast it into circ, about 6 feet , and out the drain tap.
Now came out, and nowt went in.
Flooded conservatory, burst in hose just inside it, not on long

 

[terryplumb]

Cheers. Did you check flow from TRV afterwards ,before reconnecting TRV to rad ?
You may just have shifted any restriction.

 

[joesoap13]

Yes, still nothing but a trickle coming out !
Gobsmacked.
Assumed pipe was completely blocked and needed replacing, hence putting rad back on, not expecting it to work at all until I changed it .
That’s why I cannot fathom out why it is getting hot now ?
The trickle that was coming out wouldn’t have been enough to heat rad .

If I cleared blocked, water, or air, it should have come gushing out of drain valve, but not a drop came out !
Nothing went in via hose, to my knowledge !!
Still stumped at what I did that got a positive result.