Drained and refilled system and now boiler is leaking

[sha256]

Hi guys,

I drained down my central heating system to install a new radiator. Once done, I put the pressure to 1 bar, turned on the boiler, started the central heating and started to bleed the rads of any air. After a few minutes I noticed that the bottom of the boiler started to leak in two places, taking off the bottom plate it was coming from the middle and the far right. The heaters are working albeit taking quite a while to heat up. I have a worchestor 24i junior. Had it installed 8 months ago with new rads and pipework. Any suggestions on what the cause of the leak is ?

 

[Andy128]

turned on the boiler, started the central heating and started to bleed the rads of any air

You should only bleed and re-fill the rads with the boiler off (preferably at the fused spur). Bleed downstairs rads > Refill to 1.5bar > Bleed downstairs rads again > Refill to 1.5bar (if necessary) > Bleed upstairs rads etc, etc (not forgetting the Fernox F1).

The Automatic Air Vent above the pump (located on the pump body itself) should be open and the pump bled as well. System should only be powered back up once air is removed from system. Maybe you have a bad pressure relief valve (PRV) or air vent (AAV)? The experts will be along to give you a definitive answer.

 

[sha256]

Thanks guys. Which direction do I turn the screw on the pump ?

It has stopped leaking now, so am I wrong in thinking that everything is 'back to normal' ?

 

[mogget]

Shut your eyes and hope it don't leak again

You turn the pump screw anticlockwise to let the air out, only open it just enough to bleed, don't take it all the way out.

 

[sha256]

Ah, its still leaking, although only from the middle now. Its very slow the leakage unlike before. Right, so this pump, will I need to take the cover off ? I have taken the underside plate off and this is what I can see at the moment.

 

[mogget]

Can you post a picture showing where the leak is coming from?

 

[sha256]

Attached. You can see a drop of water coming down from the second pipe on the right.

 

[McCombi]

There is a brass fitting that connects one end to the pump and the other end to the far right isolation valve. Probably leaking from there. Had two in last week. Just a case of replacing washers if so.

 

[Andy128]

Empty the condensate trap/syphon whilst your there - it's the big grey plastic thing in the middle of the photo. Just place a bowl underneath it and undo the plastic clip and watch all the gunk fall out.

Clean it up with a cloth and replace the cap (fiddly little things, I'm sure there's a knack to getting them back on). Do it every couple of months as sometimes rainwater can get in through the flu and fills up the trap (can lead to fan failure).

 

[sha256]

Sounds like a small job which is a relief

Thanks for the tip andy, I will fiddle with that!

As a side issue, when putting inhibitor into the rads, can I use any inhibitor or will I have to use a fernox branded one ? That is the label that is fitted on my boiler and not sure what to make of it.

 

[Andy128]

Fernox F1 or Sentinel X100 for the inhibitor, I can't really recommend anything else. Go for the 'Express' or 'Rapid Dose' versions, unless you already have a towel radiator (see video here).

 

[hazetimesfive]

Heating up the boiler will stop some leaks

 

[sha256]

Cheers andy, I used the x100.

One other question whilst Im here, I will have to do some more soldering/pipework on one of the rads. I will be fluxing and am aware that flux is corrosive. Do I have to flush the system ? If so, what would be the best way to do this ?

 

[Andy128]

Normally you would have to flush the system through with a cleaning agent if commissioning from new, but seeing as it's just one radiator, you can probably get away with just refilling (then adding inhibitor).

Provided nothing's fallen into the pipework of course (bits of copper debris etc), it should be ok. When finished, wipe any excess flux from the pipework to stop it turning green.

 

[sha256]

Thanks andy. And in the event some copper has fallen into the pipework ? I will be doing 4 joins for a rad (2 straight couples and 2 elbows).