The dirt that came out from my radiator!

pieroabcd

So, in the end, after rearranging all TRVs on the flow pipes and making sure to use all RT212 that are bidirectional I decided to drain the system as much as I could using that drain pipe connected to a hose.
The water came out with some dirt, but not that much.
I've refilled with 1 liter of Sentinel x100 poured in the 3 towel rails. Maybe it's too little for my house? There are 8 big radiators  and 3 towel rails.
Next year (now I really can't) I'll wash all radiators and get rid of that litter/rust/magnetite that surely has remained inside all the others.

What I noticed
The radiator at the second floor that never get hot at  the bottom now heats up everywhere, at least when it's the only one turned on. It took less than 20 minutes, that maybe is too slow.
When there other radiators on it takes much longer to heat up. It's not uniform but the bottom part nearer to the flow valve is definitely hot. Surely I have to rebalance from scratch.

The other radiators seem to be getting hotter than before. In 4 cases I've just replaced the tap on the flow with a TRV. For the other 3 I've swapped lock shield and TRV.

One thing that makes me very suspicious is that even after draining the water from the radiator that I washed and from the drain pipe at the end of the installation, the boiler pressure sensor never dropped below 1.2, even though it went to F75 error (check pump/water).
Is the pressure gauge broken? Now that I've refilled it and turned on the heating for 1.5 hour it ranged from 1.4 from cold to 1.7 at 60 degrees.

Regarding the chemical that can clean the whole pipe work, how long is it supposed to circulate to do an effective cleanup? Maybe I can add it next spring before it's time to turn off the heating?

Albermarle

AFAIK- did you add 3 litres of Sentinel X100? If so that would be more than enough.

The radiator at the second floor that never get hot at  the bottom now heats up everywhere, at least when it's the only one turned on. It took less than 20 minutes, that maybe is too slow.
When there other radiators on it takes much longer to heat up. 

20 mins to heat up when it is the only radiator on is far too slow. Try opening up the lockshield valve fully on that radiator, and see if that helps..

pieroabcd

1 litre, not 3.
The valves are completely open.
I'm beginning to suspect that the lock shield valve doesn't let enough water out. I haven't replaced it, it's still the original one.

Albermarle

pieroabcd said:

1 litre, not 3.
The valves are completely open.
I'm beginning to suspect that the lock shield valve doesn't let enough water out. I haven't replaced it, it's still the original one.

As it has not been done for a while put another litre in at some point. You only need to add it to one towel rail, as the central heating pump will circulate it around the system.

I had a similar problem, which was solved by replacing the lock shield valve, but no guarantee it will work in your case !

WIAWSNB

pieroabcd said:

1 litre, not 3.
The valves are completely open.
I'm beginning to suspect that the lock shield valve doesn't let enough water out. I haven't replaced it, it's still the original one.

Just open it a further quarter turn, and see if that helps. If not, another quarter - wee increments like that.
X100 is a good call, and should hopefully prevent any further corrosion. It isn't a system 'cleaner', of course.
Does your boiler have both a digital and analogue gauge? Do they agree?
Photo of the pipework heading to the boiler? Fitting a mag filter is easy, and should start collecting sludge right away. 

pieroabcd

I'll take pictures later, but I can tell that the pressure display is only digital. It's a. Ecotec 873

WIAWSNB

pieroabcd said:

I'll take pictures later, but I can tell that the pressure display is only digital. It's a. Ecotec 873

Confirm that model number?

pieroabcd

WIAWSNB said:

pieroabcd said:

I'll take pictures later, but I can tell that the pressure display is only digital. It's a. Ecotec 873

Confirm that model number?

Sorry, Valiant Ecotec plus 837