Air in radiators despite bleeding.

[fly7471]

Hi,

my knowledge of plumbing is very limited, I would call in a plumber but one caused tens of thousands of pounds of damage through bad workmanship, the second cut so many corners it was embarrassing AND the third caused a leak which damaged flooring. I know the people on here are experienced and professional.

I have a Worcester-bosch condensing boiler, which I believe serves a two pipe closed system, approximately 4 years old. In the spring I had eight radiators replaced with Flas-steel upright ones which get very hot. I leave in a split level masionette, the 4 radiators on the lower ground floor are fine, the 4 on the ground floor suffer with a lot of air. I am constantly bleeding these radiators, there are no obvious sign of a leak anywhere. I have noticed the steel connectors from the radiators are attached to the copper piping and no kind of special tape has been used.

So basically I'm looking for advice as to whether it's something to do with the piping or the boiler and if so can i do something about it myself, Or should I get in a pro and if so what can I look out for when they are working on my system.

Regards
Steve

 

[CES]

When you say a closed system, you mean sealed? In that every time you bleed the rads then you have to top up the pressure using the filling loop? If so then I would check the condition of your water as you may have corrosion occurring if inhibitor was not added when the rads were fitted.

 

[Deleted member 32524]

You could fit auto air vents on the system. Also when you do top up, fill it slowly. I agree with ces with regard to adding inhibitor. If the heating engineer has cut corners the chances are they have not added inhibitor. Remember the next time you employ a heating engineer to not go for the cheap guy as they always cut corners and will not come back out free of charge to rectify any problems. Look for guys that follow the benchmark. You will pay more however, you will be looked after.

 

[aceplumber]

sounds like corrosion which causes gassing , i would try a thorough flush and some inhibitor

 

[Best]

If you replaced the rads fairly recently the system shouldnt be dirty especially if it's a sealed system. I take it you are refilling system as CES has said, & to a correct pressure? I would be wary of air getting in to system from auto vents or leak at boiler pump or pipework somewhere in system. Auto vent on return pipe can suck air in when pump on. They also tend to leak. To test an auto vent if you think it could be letting air in- remove the little cap on the valve (which normally stays not tightened fully to let any air out) & put a drop of water on valve while pump on & see if water is drawn in. Manual vents are often better choice for some high parts in system.

 

[fly7471]

Thanks very much,

yes I've been topping up from filling loop to just over 1 bar, I doubt these people used an inhibitor. I'm really up for a pro sorting the whole thing out and I'm happy to pay up as long as the job gets done right, maybe some advice on how to chose a decent plumber would be the best solution thinking about it, South East London seems murder for decent tradesman . I've checked some of the radiators and there's small signs of corrosion.

Any help great fully received.

 

[dontknowitall]

Do you know of a good builder, electrician, carpenter or other tradesman? A tradesman who says "I always use him" is giving you a good recommendation. If you think about it, a builder/electrician risks his own reputation if he gives a poor recommendation and from time to time we all need to call in one of the other trades so we like to know that we're getting someone we can trust to do a decent job.

 

[PlumbBobBob]

the radiators with small signs of corrosion will need changing as they will be corroding from the inside. Most probably due to the lack of inhibitor in the system.