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Air pulled in the Heating system / life lesson

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    #62
    traume
    Registered Users Posts: 124 ✭✭traume


    Dtp1979 wrote: »
    Chances are the coil is gone on your hot am water cylinder. Blank off the coil and pressurise the system. You won’t be long finding out if that’s the culprit.
    Paullimerick wrote: »
    It may be the coil. But i doubt it as ive not heard the op on about his overflow dripping in the morning. The flow and return mixed uo going onto the cylinder is nothing lets be honest to worry about. Might have to change the MV direction. Time for a compressor my thinks.
    jimf wrote: »
    im no plumber but was wondering if the coil in cyl was gone would running off the water in a bath etc show water discolouration

    as the domestic and heating water are mixing and that's the only place they can potentially meet

    but as paul says above no suggestion of overflow dripping

    Regards the coil, I think I can exclude coil as last night I closed all loops and left only the Return and the feed connected to the Boiler and it did loose all pressure during the night, but pressure loss did seem to be slower then previsouly. There might be few leeks going on.
    Now I'm pretty sure that the issue is outside the house.

    To solve this I have to remove the boiler and check the pipes under the ground. For the same sake have to swap the return and feed pipe around.
    Most likely I will get someone in to do this.


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    #63
    John.G
    Registered Users Posts: 3,474 ✭✭✭John.G


    EV is the expansion vessel.


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    #64
    traume
    Registered Users Posts: 124 ✭✭traume


    John.G wrote: »
    EV is the expansion vessel.

    Sorry, I had a ...... moment...

    I'm really not sure how large EV is or how much pressure is inside, I have to get a new foot pump to measure the pressure. It is in the attachment.

    Regards mixed pipes, I believe the boiler works as it should, but the pipes connected to the boiled are mixed up. CH Return connected to the feed and opposite.
    Just to make sure I understand it right:
    • Feed pipe (coming from Boiler) should be split up to the motorized valves before entering the radiator loop.
    • Return Pipe (Coming from radiators) should be on the same line with EV, pressure feed and pressure gauge).
    Is that right?

    If so, how else to explain that return pipe is getting hot right after starting the boiler but feed pipe does not?

    Pipes connecting to the boiler in the attachment. Maybe it is ground level, but the water has been sitting there since yesterday..

    I think I'm going to try the Fernox or tec7 leak sealer.. Can you please convince me otherwise? If that doesn't help: have to dig the whole thing up.


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    #65
    John.G
    Registered Users Posts: 3,474 ✭✭✭John.G


    jimf wrote: »
    im no plumber but was wondering if the coil in cyl was gone would running off the water in a bath etc show water discolouration

    as the domestic and heating water are mixing and that's the only place they can potentially meet

    but as paul says above no suggestion of overflow dripping

    Its a bit strange that a system which was (semi) sealed is now leaking apparently badly especially if no system flush/chemical clean carried out?, it must have run at some stage (as semi sealed) at ~ 1 to 1.5 bar and even higher depending on the the EV pre charge pressure.
    There should now be no mixing of the waters unless a coil leak and since a properly pre charged (1.0 bar) and filling pressure (1.5 bar) 12 litre EV will loose ~2.5 litres in falling to 0 bar then the only way IMO to use the CWST overflow method is to ensure no CWST draw off then force down the ballcock for the W.level to just reach the overflow and then press up the system as normal again and it will soon be apparent if any coil leak, a CWST depending on capacity rises/falls only ~ 0.5 litres/mm.

    If, for whatever reason the EV pre charge and filling pressures are the same then the slightest displacement of trapped air still in the system will drop the pressure to zero so I would suggest the following even though maybe fairly obvious.
    Ensure that there is no connection whatsoever between the CWST and the new sealed system, ie cold feed (and NRV) now removed and blanked.

    EV (E.vessel) pre charge pressure 0.75/1.0 bar and filling pressure 1.25/1.5 bar and then re check pressure loss.

    Its also strange that there is no pressure difference between cold/hot running except that the water leakage is matching the expanding water volume.


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    #66
    traume
    Registered Users Posts: 124 ✭✭traume


    John.G wrote: »
    Its a bit strange that a system which was (semi) sealed is now leaking apparently badly especially if no system flush/chemical clean carried out?, it must have run at some stage (as semi sealed) at ~ 1 to 1.5 bar and even higher depending on the the EV pre charge pressure.
    There should now be no mixing of the waters unless a coil leak and since a properly pre charged (1.0 bar) and filling pressure (1.5 bar) 12 litre EV will loose ~2.5 litres in falling to 0 bar then the only way IMO to use the CWST overflow method is to ensure no CWST draw off then force down the ballcock for the W.level to just reach the overflow and then press up the system as normal again and it will soon be apparent if any coil leak, a CWST depending on capacity rises/falls only ~ 0.5 litres/mm.

    If, for whatever reason the EV pre charge and filling pressures are the same then the slightest displacement of trapped air still in the system will drop the pressure to zero so I would suggest the following even though maybe fairly obvious.
    Ensure that there is no connection whatsoever between the CWST and the new sealed system, ie cold feed (and NRV) now removed and blanked.

    EV (E.vessel) pre charge pressure 0.75/1.0 bar and filling pressure 1.25/1.5 bar and then re check pressure loss.

    Its also strange that there is no pressure difference between cold/hot running except that the water leakage is matching the expanding water volume.

    Maybe the system was filling up non stop when it was semi sealed.. I would never now as there was no way to measure the pressure or the amount of water entering the system.

    I will get a floor pump and check the EV pressure.


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    #67
    John.G
    Registered Users Posts: 3,474 ✭✭✭John.G


    True, the only clue you may have got is if you heard the CWST filling at the dead of night when you should be asleep!.

    Did you/someone check the pre charge pressure on the EV before installation, if not if it is located upstairs then when pressure shows 0, get a tyre pressure gauge and measure the air end pressure, when you are filling the system then the air end pressure will indicate both sides pressures as they will be equal.
    Where is the pressure gauge located in relation to the EV.?
    Also you might post the EV labeled pre charge pressure and the vessel capacity.

    Edit: Just saw your post #64 now, re boiler flow&return, you will have to check in/at the boiler itself where they should be connected and work outwards from there, the motorized valves are normally installed in the flow. The EV should ideally be connected in just before the pump inlet, if the pump is installed in the boiler flow then the EV should be connected in there before the pump inlet but as this probably would involve major piping mods it will work ok if installed in the return(s) to the boiler.


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    #68
    traume
    Registered Users Posts: 124 ✭✭traume


    John.G wrote: »
    True, the only clue you may have got is if you heard the CWST filling at the dead of night when you should be asleep!.

    Did you/someone check the pre charge pressure on the EV before installation, if not if it is located upstairs then when pressure shows 0, get a tyre pressure gauge and measure the air end pressure, when you are filling the system then the air end pressure will indicate both sides pressures as they will be equal.
    Where is the pressure gauge located in relation to the EV.?
    Also you might post the EV labeled pre charge pressure and the vessel capacity.

    Did not check the precharge for EV, all I know that there is some kind of pressure.

    I found the label on the side of the EV. 12l. 1.5bar precharge. It is actually upside down, does it change anything? Water feed is at the bottom, Schrader valve on top. The label of course is upside down. I will definitely check this. Ordering floor pump now (Needed one anyway).

    Today I filled the system to 1bar at 5pm, run the system for an hour and now at 8pm it is still at 1bar. Will check later on, but it should start dropping now.

    As you see in the attachment, I changed the screw type valve with a lever one and swapped NRV for a pressure gauge. I can't think of a way (except coil) how water could get back into the CWST.

    As I wrote previously, an extra valve was added on the return pipe (after radiator return from zones but before EV and pressure gauge). So if this valve is closed and motorized valves are closed, system is isolated, right? The return pipe is closed off and the feed pipe is closed off, so the only equipment in question are: Pressure gauge, EV, the boiler and pipes between them. I can access the pipes from the kitchen side and they are perfectly dry, floor is dry. I must assume that if I have to keep feeding water that it is leaking somewhere outside. Am I getting something wrong here?
    At least in my mind, if I have to feed water - it has to go somewhere, right?


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    #69
    John.G
    Registered Users Posts: 3,474 ✭✭✭John.G


    The orientation of the EV is OK but it must always be connected to the system no matter what combination of valves are closed, also assuming that it has its original pre charge pressure of 1.5 bar then filling it to 1.0 bar will tell you practically nothing, you might post the height above/below the pressure gauge is in relation to the EV, if its say 0.5 meter above the EV then I would suggest that you switch off the boiler when convenient then open any manual valves in your system, fill the system then to 2 bar but no higher and observe the pressure drop. It would also help if you can manually latch open the motorised valves for this test before refilling the system.


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    #70
    traume
    Registered Users Posts: 124 ✭✭traume


    John.G wrote: »
    The orientation of the EV is OK but it must always be connected to the system no matter what combination of valves are closed, also assuming that it has its original pre charge pressure of 1.5 bar then filling it to 1.0 bar will tell you practically nothing, you might post the height above/below the pressure gauge is in relation to the EV, if its say 0.5 meter above the EV then I would suggest that you switch off the boiler when convenient then open any manual valves in your system, fill the system then to 2 bar but no higher and observe the pressure drop. It would also help if you can manually latch open the motorised valves for this test before refilling the system.

    EV is approximately 1.2m below Gauge.

    Floor pump is ordered, should arrive early next week.

    I can manually latch open the motorised valves.


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    #71
    John.G
    Registered Users Posts: 3,474 ✭✭✭John.G


    Well if you pressurise to 2 bar and it falls to 1.5 bar or less it would/will definitely point to a leak of 2 litres or more.


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