Is it possible the heat exchanger in my boiler could be drawing in air?

[mutley racers]

Hi Chaps, wow Am I having some serious issues with air. Basically, my pump went a couple of weeks ago. Just starting screaming really loud. So, i flushed the system and bought a new pump.

Now, i cannot seem to get rid of the air. I have changed pump setting. The old pump was on 3, and i had it on 2. Heats up the house fine. So i tried 1. And the rads do not get very hot. So, I have just kept it on 2. The problem is though, it just keeps filling with air.

Today, I have changed it to a close coupled system, hoping this would help. But if anything, it is worse!! Also, it is always the same radiator that needs bleeding. Could this be the problem?

I have checked for pumping over, and air being drawn down the vent and all seems fine.

The reason I ask if the heat exchanger in the boiler could be causing it is, It seems when the water flows through and up out of the boiler, a gurgling noise is created.

The layout of my system is this. I have a Boiler in the kitchen with the flow and return pipes going up into the loft and down into the airing cupboard where the pump is positioned pumping down(i know its not supposed to, but that is how it has been). Then it goes into a mid position and so on.

The F&E tank in the loft is situated on the floor where the flow and returns run, and the cold feed and vent are connected behind the pump close coupled.

I have filled the system from the mains into a drain cock, but no help.

All i can think of to do now, is convert to a sealed system. But, am afraid i might blow all the old pipe work out of its fittings.

I am struggling

 

[mutley racers]

booo, no one wants to answer.

 

[RoryD]

Have you put the pump the correct way round (direction of arrow)?

 

[mutley racers]

Thanks for answering Rory. I have indeed. There is only one way it can go as its on the flow flowing in the same direction the boiler is.

 

[Best]

If you can't change it to a sealed system (which is obviously the best system), then you should raise the exp tank higher, as the pipes are same level. May have nothing to do with your problem though!

 

[mutley racers]

I have thought about that best. Really though, I am just wanting to figure out what is wrong. I have back filled the system with the mains. But, when ever i turn the boiler on, it gurgles and then i hear air. Frustrating i tell you.

I think if i have to move the f&e higher, then i may as well convert it to a sealed system. Am just worried about all the pipes going pop!!

You see, when i flushed it, the cold feed actually came out of its fitting.

Also, the pump that was in when i arrived had totally corroded at the back where the bearings were. All rusy and that. But, the rads would not fill with air.

 

[mutley racers]

also, why is it always the same radiator that needs bleeding. It is not as if it is the highest one in the house. I live in a bungalow. Have towel rails and they don't need bleeding

 

[Best]

also, why is it always the same radiator that needs bleeding. It is not as if it is the highest one in the house. I live in a bungalow. Have towel rails and they don't need bleeding

Hard to understand why a certain rad will gather air. The towel rails or modern restrictive rads will usually grab the air going around a system, but a standard rad getting air in the middle of a system happens. Explanation I heard for 1 rad getting air is that it is on lower pressure points of system, but that would only explain that happening on farthest / highest rad(s).

 

[mutley racers]

ok best. That does explain mine rad really. It is the 2nd to last rad on the system. So that makes sense

 

[Kev the gas]

When you bleed the radiator try putting a ballon over the air release!

If you can ignite the air in the balloon you have Hydrogen in the system and it needs a thorough Powerflush, not just a hose pipe on the drain cock.

 

[mutley racers]

hi kev, i have given it a powerflush. As soon as the pump went and i saw all the sludge on the flow, i flushed it.