Radiator and pipes near pump making gurgling noise

[thegancio]

A couple of weeks ago while fixing some floorboards I mistakenly put a nail through a heating pipe under the floor. An emergency plumber was called and he proceeded to saw off the section and resoldered a new section of pipe, the leak is not fixed.
Since then every morning at 5:40 AM when the CH kick in I get woken up by gurgling/bubbling noises from a radiator near the section that was repaired (It stops after 10 mi or so and no noise when the system is hot), I have tried to bleed the radiator for 2 weeks but no air come out and the radiator is hot throughout, recently I have started hearing some bubbling noises near the water storage tank and pump.....any ideas?

Could the plumber have moved/touched another pipe while working and now there is air entering the system via a small crack?

 

[Madrab]

I take it it's a tank fed system? Did he bleed the pump? Have you bled all the rads, especially the ones at the highest points in the system?

 

[thegancio]

Hello Rob,

Thanks for the reply.

Yes it is a tank fed system, no he did not bleed the pump, yes I have bled the 2 radiators at the highest point twice a day for 10 days...only on the 1st day air came out, since then just water but the noises continue.

P.S. Should I bleed the radiators only when the system is off or is it ok to do it while it is running too (Being careful not to get burnt)?

 

[Madrab]

It's best to do it when the system is off, least chance that air isn't being pushed round the system and it should then settle at the highest point but do try to bleed all the rads. You say the leak isn't fixed? How do you know that? He needs to comes back and fix it properly then.

Make sure your F&E tank has water in it and the feed pipe is under the water level if on the side of the tank.

 

[thegancio]

Hello Rob,

Thanks again, the leak has been fixed right away no more water is leaking out and the pipe was soldered again.

What I meant is that in order to solder the damaged pipe he had to pish and move a little the other pipes that were near the damaged one and that lead to the radiator that is now making noise. So I am wondering is somewhere down the pipe a small crack formed and now every time the CH starts it "suck" air into the system from this small crack. No water leakage that I can see is happening.