Air in System

Discussion in 'Plumbers' Talk' started by Zippy177, Nov 9, 2019.

  1. Zippy177

    Zippy177 New Member

    Hi All

    I am new to this forum and would like some advice please regarding air getting into heating system. I am finding that I have to bleed the system approximately once a week, if I am only using the Hot Water side then its about every two weeks.
    Its a standard system about 30 years old, if we are running just the hot water then air collects in the main circulation pump, if I am running heating as well then air collects in the radiators upstairs. I have checked the system for leaks and can find none, the circulation pump is running at speed two as it appears the faster the pump runs the more air the system acquires. The only way I can see air getting in is through the hot tank over flow into the cold water tank?.

    My question for all you knowledgeable people out there is can i put a non return/one way valve on the end of that over flow pipe back into the tank or is this suggestion not a recommended option.

    Many Thanks in anticipation of your suggestions on how to overcome this problem

    Zippy177
     
  2. terrymac

    terrymac Well-Known Member

    No ,don't do anything to the vent pipe from hot water cylinder.
    Do you have a smaller loft tank that feeds the central heating system with water ( called an F&E tank) ?
     
  3. Zippy177

    Zippy177 New Member

  4. Zippy177

    Zippy177 New Member

    I should also mention I have fitted a sussex flange on top of the hot water cylinder when I put a pump onto the shower that services the ensuite
     
  5. The Teach

    The Teach Well-Known Member

    Is air entering the system a new event ?

    Maybe some system changes have happened since it was installed or its originally installed incorrectly,need to start somewhere ;) there are many reasons why air rapidly builds up and many possible remedy's.
     
  6. Zippy177

    Zippy177 New Member

    No not a new event but has become more noticeable over the last 2/3 years. Since I have owned the property approximately 5 years I have replaced the timer controls and thermostat, put in the pump and sussex flange, added rad stats and replaced the micro bore that had been added during by a contractor during a bathroom refurb, the system is all now 15mm.
    As you said i need to start somewhere so if you could give me a direction/area to start looking it would be very appreciated.

    Thanks
     
  7. terrymac

    terrymac Well-Known Member

    Is the water level in the f&e tank around 4 inch deep , if you press down on the ball /float does the valve allow water in ?
    When did you last drain the system, if you ever have ,and did it fill OK ?
     
  8. Zippy177

    Zippy177 New Member

    The water in the f&e tank is at least 4inch deep and the ball valve is operating ok and allowing water into the tank. I last drained the system about two years ago when it was flushed through and protector added, however I did notice a build up of scum in the tank and the water does not appear very clear today when i checked it, as far as i remember it filled ok just the normal air issues when refilling, these were all bleed out.

    Ta
     
  9. nigel willson

    nigel willson Well-Known Member

    May not be air. When you next vent rads , put a match to the gas . If if burners with a colourless flame , it’s hydrogen. This means system corrosion taking place . Ps don’t set the curtains alight
     
  10. Zippy177

    Zippy177 New Member

    :) The next time I bleed the system i will check for hydrogen. Is it possible to get an auto bleed valve I could put into the circuit?
     
  11. Jimbo

    Jimbo Well-Known Member

  12. Jimbo

    Jimbo Well-Known Member

  13. nigel willson

    nigel willson Well-Known Member

    You could ,but if that is the problem u need to sort out the corrosion 1st
     

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