Mains water flush

[Bradshell]

On my Turbomax, i am wanting to mains flush the return leg of a radiator in an upstairs bedroom. I removed the rad a bit ago to decorate and immediately the boiler started cutting off after reaching the temp set on the boiler. I suspect that some sludge or crud has got into the leg as quite a bit of black water came out of the rad and now its slightly restricted. All the rads get warm/hot etc but before i dive into a powerflush in the new year, i want to do as mentioned above.

It has a filling loop fitted but i am just wanting to clarify that i can close all rads and the flow isolating valve and then water mains flush via the CH return valve upto the radiator upstairs (draining from the radiator valve).

I know some will say just powerflush etc but id like to try this first before forking out for it. Also ive used x800 cleaner an loads of junk was collected in the magnaclean which i've cleaned 3 times, each times less and less being removed. I've checked the ntc sensors, replaced the pump with a another one, checked the DV isnt stuck etc. And the hot water works fine

Thanks

 

[terryplumb]

Don't fully understand what you are trying to achieve ,is it the two pipes on the removed radiator that you want to establish if they are blocked ? If so just open one valve at a time ,if water flows out strongly the pipes not blocked !
Or have I missed the point of what you are trying to establish ?

 

[Bradshell]

The return leg off the rad i think is slightly restricted. When i last opened it, it wasnt a strong pressure

 

[terryplumb]

I assume its the lockshield valve that you opened. So with a helper to open the filling loop on the boiler ,and boiler switched off and cool , increase pressure to 1.5 bar and tell helper to keep it there ,adding more water as needed. Whilst you open the valve fully.( obviously the radiator is not in place )
A flexi hose attached to the valve and into a large bucket will make life easy ,and let it run full belt for a minute .see what the result is.

 

[Bradshell]

Spot on. Thanks for the reply. Fingers crossed something comes out. If its crystal clear then i can only imagine a powerflush is needed. Trying to make sure something small isnt fixed by going all in on a powerflush

 

[terryplumb]

What makes you think you need a power flush ? You said "all rads are getting warm/ hot etc ", and before you removed one rad ( which I assume was heating perfectly well also ) you didn't have any worries ? Domestic hot water is fine ,and the mag filter is doing its job together with the cleanser ?

 

[Bradshell]

Yes to all of the above. Since the rad went back on the boiler just gets to temp then cuts off. Before it just stayed on until i knocked it off on the boiler

 

[JohnD]

you did re-balance that radiator when you put it back? You didn't just wind the lockshield fully open?

 

[nwgs]

you did re-balance that radiator when you put it back? You didn't just wind the lockshield fully open?

That makes no sense.

 

[Bradshell]

No i dont think so. I didnt take note of how far open it was open.

 

[nwgs]

No i dont think so. I didnt take note of how far open it was open.

Is your boiler knocking off before all the rads get hot

If it is I’d say you’ve a restriction in your return or a blocked filter in the boiier. Not sure it has one?

 

[Bradshell]

They all get hot but some rooms arent getting warmed up enough because the boiler knocks off before they get chance too. I turned up the CH dial to full and it does the same but obvsiously it heats the water up longer to 82 i think then cuts off and fires up again 2 mins later for a 5, maybe 10 mins and cycles

 

[terryplumb]

I thought the rad that you removed was not heating up ,as you thought there was a blockage. But are you saying this rad gets very hot to touch and so do all the others ?? If they do then its highly unlikely that you need a power flush ,but more likely a boiler issue.

 

[Bradshell]

Yes they all get hot. I thought the issue was related to the return leg of that rad because after i fitting it back, thats when the issue started with the boiler cycling. It was wprking perfect before.

 

[Bradshell]

I am confused as to how removing a rad and bleeding it back can cause the boiler to start cycling. I didnt change anything on the boiler etc. Could it be balancing issue?? The hot water return seems rather hot, similar to the flow temp but id need to confirm it with a thermal camera from work.
I am partly tempted to drain down and then check the inside of some of the return leg pipework at the bottom of the boiler prior to the magnaclean? See if there is any signs of sludge or restrictions. Kind of cluthing at straws with it all now