Cold radiators downstairs; hot upstairs

[Deleted member 117153]

Hi all,

I've got a bit of a head scratcher with 3 cold radiators downstairs that are full of water. Radiators upstairs are heating up nicely, as are another 2 downstairs that are fed from above.

There are two drain points - 1 in the hall on a falling pipe (which drains upstairs) and 1 in the kitchen which drains the three downstairs rads. I had wondered if an airlock trapped by the water above would be preventing the downstairs from circulating, so have drained both sections (after locking 3 way valve open at mid-point), bled downstairs then upstairs. The downstairs radiators are full of water but still cold so I have tried the airlock removal trick of isolating rad, removing vent and attaching hose, hen opening up each side in turn. This has got the pipes downstairs vaguely warm but they are then almost immediately cold again.

Turning off all upstairs lockshields gets the downstairs radiators warm, but not piping

The system is made up of:

Worcester Green Star 24Ri boiler in kitchen
Cylinder, Drayton AM1 and pump in airing cupboard
F&E tank in the loft


The pump (not sure what brand as it is fitted close to the wall) is set on level 1 so wondering if I should try increasing the level?

There is a Voss Purg-o-matic fitted next to the 3 way valve but opening it is does nothing... No air, no water, even when the pipe it is attached to is hot. Guessing something has seized in it somewhere...

Any advice or help would be greatly appreciated.

 

[exedon2]

Start by turning of all rads that are working off turn pump up to 3 see what happens. Pump is a grundfos probably a 15/50

 

[SJB060685]

Is this a new problem? Is the pump running?

 

[Deleted member 117153]

Hi all,

I've got a bit of a head scratcher with 3 cold radiators downstairs that are full of water. Radiators upstairs are heating up nicely, as are another 2 downstairs that are fed from above.

There are two drain points - 1 in the hall on a falling pipe (which drains upstairs) and 1 in the kitchen which drains the three downstairs rads. I had wondered if an airlock trapped by the water above would be preventing the downstairs from circulating, so have drained both sections, bled downstairs then upstairs. The downstairs radiators are full of water but still cold so I have tried the airlock removal trick of isolating rad, removing vent and attaching hose, hen opening up each side in turn. This has got the pipes downstairs vaguely warm but they are then almost immediately cold again.

Turning off all upstairs lockshields gets the downstairs radiators warm, but not piping

The system is made up of:

Worcester Green Star 24Ri boiler in kitchen
Cylinder, Drayton AM1 and pump in airing cupboard
F&E tank in the loft


The pump (not sure what brand as it is fitted close to the wall) is set on level 1 so wondering if I should try increasing the level?

There is a Voss Purg-o-matic fitted next to the 3 way valve but opening it is does nothing... No air, no water, even when the pipe it is attached to is hot. Guessing something has seized in it somewhere...

Any advice or help would be greatly appreciated.

Start by turning of all rads that are working off turn pump up to 3 see what happens. Pump is a grundfos probably a 15/50

Thanks exedon2, will give that a go and report back
[automerge]1604436515[/automerge]

Is this a new problem? Is the pump running?

I should have said - this is a new problem after fitting 2 new radiators with TRV and lockshield. I have wondered if it is to do with balancing...? I have tried shutting the lockshields on the new ones off entirely, but it doesn't seem to have led to any improvement.

The pump is definitely running and doesn't seem to have any air trapped in it having opened the bleed valve.

 

[SJB060685]

Thanks exedon2, will give that a go and report back
[automerge]1604436515[/automerge]

I should have said - this is a new problem after fitting 2 new radiators with TRV and lockshield. I have wondered if it is to do with balancing...? I have tried shutting the lockshields on the new ones off entirely, but it doesn't seem to have led to any improvement.

The pump is definitely running and doesn't seem to have any air trapped in it having opened the bleed valve.

This does sound like a system balancing issue.
Now that you've added two new radiators it sounds like the pump is struggling and/or the system isn't balanced. First you need to get the system pressure and flow rates in the right region. Try turning the pump setting up one. See if this improves the new radiators. Obviously have the valves open, not closed as you said above? Once you have the pump on the right setting then you need to balance the system, this can take some time. Dont be tempted to whack the pump on max setting and strangle it to achieve correct operation as this wastes energy. Ideally you want the pump on the lowest setting to achieve system requirements.

 

[exedon2]

Now that's a very different scenario new rads not working!
Pics of offending rads valves and pipework connecting them would be good.

 

[Deleted member 117153]

Hi all,

I really appreciate your replies.

The new radiators are not the problem ones but I wonder if me changing TRVs and lockshields will have upset the balance of the system.

I ran the heating with all rads open and the pump on 3 and ALL radiators got hot! So no airlock or anything of that nature. I then let the system cool and tried with the pump on level 1 and found that the three that were not getting hot were warm, rather than hot. I will try the pump on level 2 tomorrow, but wonder if the upset in balance means the pump (currently) needs to do that little bit extra to get the whole lot nice and toasty.

As a DIYer who has refitted a couple of bathrooms and changed a few radiators and TRVs, balancing a system on the face of it seems quite difficult...?
I'm looking to fit towel rads in the bathroom and little shower room where there are currently 600 wide double panel single convector rads so thinking I might get a local plumber in to do that and do all the balancing.

 

[Harvest Fields]

Sorry. I haven’t read the previous posts but If you have extended the radiator circuit I would check the pump as it looks really old and may not have enough umph.