radiator issues, not heating equally

[FNG]

hi,

I noticed a few weeks ago that one of our radiators was hot at top and cold at the bottom, I thought it could have been a dodgy valve as this radiator was only half open for years because it used to cause knocking in the pipes if fully open. Or the system unbalanced.

however, we now getting the same in others so I suspect it's sludge.

the base system is I suspect 30 years old though one loop is on crappy narrow plastic pipes from around 10 years ago.

to add to the woes we had lots of work done this year including new radiators in 3 rooms, moved/new pipes and the whole boiler also moved from bathroom to kitchen.
Never saw any inhibitor being used (though not around for 80% of their work) and they are reputable tradesmen sub contracted in by our very reputable builder/project manager but obviously all the pipes and radiators have been disrupted with plenty of full drains and refills.

So,

As I don't want to power flush the system as this is beyond DIY and would cost a significant amount of money. Putting together advise/comments from lots of different threads/sites it seems to be recommending a chemical cleaner, drain down and then refill with a inhibitor.

Would this be worth trying first?

What are the recommendations and are there any handy videos/tips on how to add the stuff into the system (especially as I don't want to be doing it via the boiler)

TIA

PS, boiler seems fine. It was serviced only last week and the engineer never raised any concerns re pump etc.

 

[Agile]

Probably sludge in the bottom of the rad.

Take it outside and flush through with mains water.

If its single panel it will probably work well as you may be able to poke if required with a metal rod.

If double panel then could be a real pain!

Tony

 

[dominoman]

You could try adding a sludge remover and see what that does. If your system is badly sludged it won't do very much at all though. It's like trying to shift a mountain with a teaspoon.

To get the sludge remover in to the system put it in the small feed tank if you have an open system (remember to drain some water out of a radiator after so it actually enters the system).

You really need to get rid of the sludge though. If like me you don't want to powerflush you could try a DIY job using mains water. See //www.diynot.com/forums/viewtopic.php?p=253454

That should force most of the crud out into the drains, especially if you tap the radiators with a mallet as you do it. You could then run the sludge remover for a couple of weeks to finish off the clean and get rid of the remaining magnetite.

You should also fit a magnetic filter like a Fernox TF1 or Magnaclean while you've got the system drained.

I am going to do a mains flush next weekend, so will be interested to see how you get on if you do want to try it.

 

[FNG]

hi,

don't want the expense of fitting a filter

It's a sealed system, no tank.

I have no idea how bad the sludge is, it may be bad, it might not.

I read the thread on the diy flush, I don't really want to be touching the boiler or the pipes if I can because if anything happens it's a whole world of pain.

ta

 

[St0rmer66]

Fernox F5 Express makes it easier.

 

[FNG]

Ok,

I drained about 2 L out of the system via a valve on one of the ground floor radiators.

I then added a sludge remover to the very top radiator in the loft, sealed it back up and topped up the system again

I have the heating cranked up to 21 degrees just for tonight to get the water flowing round.

Lets see what a difference this makes

 

[dominoman]

Dont forget to come back and let us know.

 

[JohnD]

bleed some water out. What colour is it?

What colour was the water before you added the chemical?

Which chemical did you use?

 

[FNG]

Right, an update

I could only get to wickes at the time and they only sell their own brand stuff in the shop, everything else is online only which is annoying.

Anyway, I bought 500ml of cleaner, drained a bit out of the system, added it, refilled and bled everything and left it for a week.

It didn't make a much of a difference to be honest.

Anyway, yesterday I got some sentinel 400.
drained the entire system, took 2 of the main radiators off and washed them through and refilled with the sentinel in place.

There's some difference already but the radiator that started the issues still has a cold spot. Now I know it's not the value or radiator as both were cleaned but the left pipe is very much colder than the right so I suspect the issue lies somewhere in that section of piping.

Unfortunately, that piping in that section seems to be 10mm plastic and I suspect that there is a blockage in there somewhere

The water it self was clear at first but gradually got worse as it drained till it ended up black.

The plan is to let the sentinel run for a few weeks and then see what it's like and what other options are available.

 

[JohnD]

if the water goes black, that's a good sign, it's the sediment being washed away into the water.

If you turn off all the other rads for a while, that will maximise flow through your bad part.

If you have a rad with a cold spot in it, taking it off and hosing it will help, but you can also mechanically move it. Opinions differ, but tapping the rad with a rubber mallet, and using a hammer drill (with a block of wood or hard rubber to protect the paint) are two methods some people use that can loosen sediment.

 

[Agile]

X400 needs 4-6 weeks to work!

But X800 is stronger and works in 3-4 hours and needs removing after 24 hours.

But you should circulate it first though just the bad rads buy turning off the others.

Tony

 

[FNG]

Ok,

the heating and cold spots have improved

It's not perfect but it is a distinctly better

I am currently draining the system to remove the x400 and water is looking like strong tea from the very start

the first time, the water was clear till I got to the last couple of buckets.

The plan is to refill it with normal water and leave it till payday.

Then drain add another batch of X400 for another 4 to 6 weeks.

Then see what the water/heating looks like then.

Hopefully that will be the end of it and I can just refill it with an inhibitor

 

[dominoman]

Great that you've done that. It's satisfying to get the system cleaned out.

If it doesn't work fully check that the radiators are properly balanced. I did what you did and even ended up resorting to a powerflush, but the problem all along was just that the 90% of the hot water was going via 2 of the radiators and the others were getting barely a dribble. Plumber did the balancing and now it works great.

 

[JohnD]

if you can afford an extra £100 or so, add a system filter. The sediment will continue to appear for months, and it is very gratifying to empty out a filter and see how much has been trapped, long after you did your chemical clean. There are now chemicals that you can leave circulating permanently, intended to loosen particles so that the filter can trap them.

 

[FNG]

hi,

done a 2nd clean and the water still looks very very inky

I have refilled and put an inhibitor in for the moment

So, I am interested in fitting a filter such as the Fernox TF1 as a long term solution but I was wondering if one can be fitted?

Our Vailent combi boiler is in a kitchen cupboard and the pipes underneath it are not readily accessible.

The only accessible pipes in the house (discounting any under the floorboards) are two 15mm plastic pipes which are in a large cupboard on the 1st floor running vertical feeding the radiator in the loft.

What would be the best filter to add then?

Can they be fitted to these small plastic pipes? The Fernox only seems to have 22mm and 28mm copper compression fittings which I assume are for copper pipes
Would it be possible to fit a 15 to 22 speedfit expander onto a length of 22mm copper then into/out of a TF1?

Given that one pipe flows up and one down would it matter which it was fitted to? If so how do you tell which is which?

Does it matter where in the network the filter is fitted? Are they fitted next to boilers just for convenience?

Would it better to fit it horizontally under the floorboards on the ground level?
The downstairs radiators seem to be on loops of 15mm copper fed from 22mm copper

Many many questions

TIA