Confused, not dazed but definitely confused.

[WanderOverYonder]

Evening all,

Need some advice if you don't mind.

I had to change an old radiator in our kitchen due to it leaking. So on Wednesday, I dfained the system and fitted a nice new Kudox double 600x1200 with a danfoss ras c2 TRV.

Refilled and boiler kicked in after bleeding fully. Now having some issues.

We are in Scotland so might not come as a shock its sll on 8mm microbore. Sytem is 8 radiators, 4 up and (yep you guessed it), 4 down.

From closest the boiler we have; upstairs
1. Towel rad in bathroom
2. 500x500 in son's room
3. 500 x 500 in spare room
4. 300 x 1100 in main bedroom
Downstairs
5. 600 x 1200 in hall
6. 600 x 1200 (new) in kitchen
7. 700 x 1100 in livingroom
8. 500 x 1000 in spare room

1, 2, 3, 5 and 8 are all hot. 1, 2 and 3 are very hot.

4, 6 and 7 are merely warm and are cold at the bottom.

Now sludge has been suggested but my confusion there is that the kitchen rad is only fitted 2 days. Living room only 2 weeks old and bedroom less than a year. So could it build up so fast?

I have put Sentinel X400 in via the kitchen rad and been running it but no real joy.

Any suggestions would be appreciated.

Cheers.

 

[Crofton Gas]

Have you tried balancing system, ie throttle down the hot radiators on the lockshield? Could be air locks...

 

[WanderOverYonder]

I have throttled down all the hot ones. Closed LS completely then opened one half turn.

 

[Crofton Gas]

And do the others get hot? Or try turning all the rads off apart from one of the cold ones, if that gets hot there's a circulation problem, sludge or air

 

[WanderOverYonder]

It didnt really make much diff. Will try the latter suggestion tomorrow.

Any tips if its air? Or sludge for that matter?

 

[Crofton Gas]

If its air, you will need to shut all radiators, then with the boiler/pump running open one rad and vent into bucket until it's hot, then close and repeat on other radiators.

If it's sludge, your need a powerflush of the system

 

[WanderOverYonder]

I have read mixed views on powerflushing 8mm systems. Is it likely to cause issues?

 

[Crofton Gas]

Depends on how it's installed, if your near Edinburgh, get hold of Ryan from g.d mills plumbing and heating... highly recommended

 

[WanderOverYonder]

Cool, cheers man.

 

[dilalio]

It's a common problem when draining down. If there's an f&e and this is full of crud, it can pull that down through the pipework, as well as any sludge that is otherwise settled during normal circulation. Get a filter installed if/when you have it flushed.

 

[WanderOverYonder]

If its air, you will need to shut all radiators, then with the boiler/pump running open one rad and vent into bucket until it's hot, then close and repeat on other radiators.

If it's sludge, your need a powerflush of the system

Question on this, if I isolate a rad and disconnect it, when I open the lock shield on the return side should I get a flow of water or is that only expected on the inlet side?

 

[dilalio]

You should get water from both, unless one at a time which can be down to vacuum.

Blockages/airlocks can be on either flow or return or both.

Closing down other rads and running the system will hopefully use pump pressure to clear the air/blockage.

If blocked, it can sometimes take an age to get the blockage broken down and moving, especially through small bore waterways (rad valves etc). And sometimes it needs the more powerful pumping that a powerflush provides.

I'd try focusing your pump on one run/rad at a time and then maybe drain that circuit before proceeding to the next. Also make sure your f&e is cleaned out.

 

[dilalio]

Is it a sealed or vented system?

 

[WanderOverYonder]

Cheers. Its vented. F&E tank didnt look overly dirty when I drained it. Not to say it wasnt dirty enough to cause an issue though. Got heat at all inlets so does logic dictate the issue is on the return side(s)?

 

[dilalio]

Could well be. You've gotta get it all moving.
Focus the pump on each individual rad.

Again, the benefit of a flushing machine is that you can (and do) reverse the flow throughout the process.