Radiator Sludge Issues

[JMC51]

Hi. Had a new radiator fitted recently and during cold snap noticed it was showing signs that we may have pulled sludge into it
Normally flush system through every year but been a bit lazy the last two.
Tried balancing trick but to no avail
So injected Fernox into Rad with no immediate result. Eventually very slight improvement.
The radiator is downstairs and two other radiators on that floor. If I now isolate these two there is a vast difference in temperature.
I am thinking that the Fernox is slowly doing its stuff and with the two rads isolated the pressure is concentrated through the dodgy rad thus giving me heat and
hopefully helping the Fernox do ts bit.
Your thoughts would be appreciated

 

[Mottie]

Are you able to remove and refit a radiator? If so, you can’t beat taking them off, taking them outside and flushing through with a hose pipe. Drain, flush, half fill, give it a good shake, rinse, repeat until running clear.

 

[JMC51]

Thanks, Mottie. Removing rad is on my list of options but trying to avoid.

 

[dilalio]

Why not try a drain down and mains flush? If you have an open vented system then clean out the f&e tank first and then let it continuously fill and flush through the system exiting a drain point.

 

[JohnD]

Which version of Fernox are you using?

Why haven't you fitted a Magnaclean or similar yet?

Is the feed and expansion tank pumping over?

 

[DP]

If I now isolate these two there is a vast difference in temperature.

Not sludge, lack of flow possibly plumbing issue or other factors.

Balancing is first port of call
Then flow and return temperature check at the boiler with ALL finals calling for heat.

Water to three radiators is insufficient
Water flow to new radiator possibly more resitive hence poor heat output, hence when other radiators are turned off, new rad heats up

Additive have nothing to do with it

Fail to see the need for annual water change. All you are doing is introducing fresh water with included air, oxygen in which will corrode system till oxygen depleted.

 

[Madrab]

Normally flush system through every year but been a bit lazy the last two

Fail to see the need for annual water change

Why do DIY'ers think this is a good thing to do?

A CH system, once conditioned and mature is like a tropical fish tank, it shouldn't need any real major cleaning/flushing on a regular basis, in fact all that's happening when it's flushed is introducing more fresh O2 that promotes corrosion in the system.

The system should be monitored yearly for colour/turbidity and if the system water stays clean and everything heats up properly then leave it alone.

Back to your issue - As suggested - You need to check flow to that radiator is sufficient, was it extended off of the other rads or does it have it's own supply from the main CH backbone?

 

[JMC51]

Thanks to all for replies.
Probably should have been clearer - the new radiator was like for like a replacement for a leaky one so I assumed balancing was not an issue.
Assumed it was sludge. I have only ever once had a sludge issue and it was easily cleared.
Will look at balancing again,

 

[dilalio]

Thanks to all for replies.
Probably should have been clearer - the new radiator was like for like a replacement for a leaky one so I assumed balancing was not an issue.
Assumed it was sludge. I have only ever once had a sludge issue and it was easily cleared.
Will look at balancing again,

When you replaced the new rad, did you open its lockshield to the position it was previously?

 

[JMC51]

Well, just bit the bullet. Wifey is not happy with the radiators not matching in lounge !
So I am now replacing the other one and fitting a Filter at same time - being done by a plumber.
Radiator was fitted by BG and lockshield turned out to be only partially open although I may have had a senior moment.
Now getting a lot more heat. Will let the experts fine tune it when they come !
Thanks to all who replied.

 

[DP]

Will let the experts fine tune it when they come !

What experts.
A DIY task that works quite well
Run the boiler and let the system come up to temperature
Then at each radiator feel the two connecting pipes
One will be ouch hot and other not so ( aim for 11 degrees for cast iron heat exchanger or 20 for low water content or condensing boiler if you have means to monitor temperature)
Record your findings on paper
Now return to first radiator and adjust the valve that is not the TRV or has a blank cap ( not always the case) to create diffential temperature if not already that
This exercise is time consuming but finally you should have all the pipes with aforementioned differential across them including the pipes out of your boiler
In a nutshell, this will ensure ( plumbing permitting) that each radiator has required amount of water flowing through it
Footnote. Towel rails often have too much water flowing through them resulting both connected pipes being the same temperature