Furthest radiators poor performance

[rebelbuttmunch]

Hi,

Ive turned off all radiators except for the two that are last in line from the boiler and pump.

They are extremely slow to heat.
The 2nd-last rad has hot inlet pipe, cold outlet pipe. The rad is hot at the top and cold at the bottom
The last rad has a hot inlet pipe and a cold outlet pipe. The rad itself has struggled above room-temp

Ive bled both and only water comes out.
Im thinking that
a) the pump isnt strong enough (getting old?)
b) The rads are full of gunk
c) something else entirely?

Any ideas?

 

[clf-gas]

Poorly balanced cuasing option B.

 

[rebelbuttmunch]

Poorly balanced cuasing option B.

Can it be a balancing problem with all other rads except these two turned off?

 

[kevindgas]

partial blockage of the outward supply pipe with sludge would be my guess.
get some silt free &/or cleanser put in system and run for a couple of days, then drain and refill system add some inhibitor on refill.

 

[rebelbuttmunch]

partial blockage of the outward supply pipe with sludge would be my guess.
get some silt free &/or cleanser put in system and run for a couple of days, then drain and refill system add some inhibitor on refill.

Hmm, You know, I had a look around my system and the Einsteins that installed it didnt put in a drain-tap or whatever its called. In other words to drain it, Id have to disconnect a rad and figure out a way of catching all that water. Do you think I could just use the chemical and not drain the system?

 

[clf-gas]

The rad is hot at the top and cold at the bottom
The last rad has a hot inlet pipe and a cold outlet pipe

You want to be taking those two rads into the garden first and flushing with your hose pipe.
Replace the rads but before opening the valves add you system cleaner, now open valves and bleed. run for a few days, drain and flush system, (at this point add some drain valves.) re fill and enjoy a cosy winter

Dont forget to balance system, see FAQs

 

[rebelbuttmunch]

The rad is hot at the top and cold at the bottom
The last rad has a hot inlet pipe and a cold outlet pipe

You want to be taking those two rads into the garden first and flushing with your hose pipe.
Replace the rads but before opening the valves add you system cleaner, now open valves and bleed. run for a few days, drain and flush system, (at this point add some drain valves.) re fill and enjoy a cosy winter

Dont forget to balance system, see FAQs

Flushed rads, and reconnected. Balanced system. so far so good. 'll leave it a week and I'll flush the whole thing out. When I drain the system should I leave the header tank alone, so as to create a flush of clean water through the system or tie it up ?

 

[Agile]

You did not say what you got out of the rads!

Did you do the "bucket test" on the supply pipes? See FAQ for details.

Tony

 

[rebelbuttmunch]

I struck oil inside the rads. Well at least it was a black tarry goo that came from the rads.

I didn't do the bucket test, I'll put that down to ignorance. I'll try that next time though, its a sound idea.

 

[doitall]

You should clean the header tank out, because if you have a load of sludge in it, you will block the cold feed, and have more problems.

 

[rebelbuttmunch]

Good Idea.

Ive poured a litre of cleansing chemical into it, before I filled the rads. I'll let it do its stuff for a week or so.

 

[rebelbuttmunch]

So, Im going to drain the system down today.

2 questions though
Does is matter which downstairs rad I should disconnect to release the water? (I dont have a drain valve)

And

Should I leave the header tank operational so as to create a clean flush of water through the system as I drain it? (This should also clean the dirt from that tank)

Thanks!

 

[doitall]

You need to get the bulk out of the tank or it will block the cold feed.

The smallest rad is easiest to work with.

You can flush it out once you have the hose pipe safely attached.

 

[kevplumb]

and to reiterate once you have it drained

FIT A View media item 14822

 

[Agile]

Those give me such a lot of problems that I only fit a iso valve as I can then fit a hose pipe later and they dont leak on the floor like the drain cocks and they dont have washers to stick closed.

Tony