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Air pulled in the Heating system / life lesson

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Comments

  • Registered Users Posts: 124 ✭✭traume


    Today I opened up the MagnaClean, I didn't expect to see so much sludge. I have to consider Power Flush. See in attachment. I doubt I hewting system cleaner will help here as if there is so much sludge on the filter and if bleeding radiators black and smelly water comes out: either i remove the radiators or get powerflush.

    I checked where E.Vessel is connected and it is connected to the feeder pipe approximately 1.2m below NRV. Then I can see that radiator return pipes connects to the same pipe and then goes down in the floor. It is not clear in the images, but added them anyway.

    E.Vessel has the air in it. I don't know what pressure is in, but it is definately there.

    What is strange - after disconnected the Magna Clean I let in the system approximately half litre of air and it is right before the Circulation Pump, but it started right up without a hickup and without airlocking. I let it run for a few minutes and opened up the bleeding screw on the circulation pump - no air.

    Looks like for now, I can't do much more then convert to sealed system and then powerflush.


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭John.G


    Maybe the magnetic filter was impeding the flow into the pump suction and cleaning it helped, there certainly seems a good build up, wonder how much it has removed from the rads (wall thickness etc) and will the increased system pressure show up any weaknesses as indeed the power flush may too.

    The E.vessel connection point is on the return at any rate.

    Should also have asked where the pump is installed (boiler flow or return) and its make/model and present setting. I can see the pump from the photo but not the setting.


  • Registered Users, Registered Users 2 Posts: 478 ✭✭rightjob!


    I wouldn’t convert it to a fully sealed system,its not going to do much for you.(if you already have a semi sealed)

    If you have air coming in its either
    -a leak
    - air getting sucked in at vents or if you have an open vent system.
    -the expansion vessell is burst and causing the safety valve to open and let water out.

    That system definitely needs a power flush from looking at the photo of the magnaclean.
    If you are going down the route of getting a powerflush, they will more than likely stick a filling loop on it for you.


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭John.G


    Fully sealed systems tend to be set up with minimum pre charge/filling pressures of 1/1.5 bar so the lowest system pressure will generally be ~ 1.5 bar so the system will generally be 1.5 bar with a minimum of 1.0 bar when cold whereas semi sealed results in a pressure of ~ 0.4 bar (static head) every time the system cools down so on start up will tend to pull in air somewhere if any restrictions or whatever in the system, I know of one system which was converted to semi sealed because of ongoing (air ingress) problems with a vented system and even though it improved the situation, it didn't cure it but changing to fully sealed did. Semi sealed will work in the majority of cases though and is far more forgiving on very old systems due to the lower pressures involved.


  • Registered Users Posts: 124 ✭✭traume


    Update:
    Yesterday converted to Fully sealed. Pressure is dropping very rapidly, approximately 0.2-0.4 bars every hour.
    No visible leaks. I didn't have pressure guge previously and could not judge the pressure, now I can.

    So what I have done now is - I added a valve on the return so now I can isolate the system (motorized valves for each zone). It is needed to find out if the leak in the house or it is Hotpress-Boiler run. Waiting and hoping that pressure will drop now so I know that those are the pipes which are accesible.
    They can't be leaking from hotpress to outer wall as I went through every inch and could not find a drop of water. So either Exterior Wall to Boiler or somewhere in the house.

    Is it worth trying Fernox Leak sealer? At the minute 2bars are lost in couple of hours, I would imagine it should be quite large leak. I read a lot of similar cases fixed with Fernox Leak sealer but I'm afraid I will clog the pump or heat exchanger?!

    Else, Return and feed pipes on the boiler are mixed up...After starting the boiler first pipe to heat up in the Hotpress is the return pipe (the one where Water is topped up and no motorized valves), so I have to get this sorted as well. If i understand from you guys right - It can't be the cause for the leak anyway, but it explains why air was pushed in the feed pipe instead of radiators.

    Thanks everyone for good ideas!


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭John.G


    A few queries;

    Where is the pressure gauge located? (eg ground floor etc)
    Where is the EV located?
    What is the capacity of the EV.
    What was the EV pre charge pressure?
    What was/is the EV filling pressure? (cold)

    Regarding "Return and feed pipes on the boiler are mixed up", if they were then the boiler stat would be measuring the return temp and the actual flow temp would have been anything from 10C to 25C higher, wonder what effect the reversed flow has on a condensing boiler re corrosion.
    I would check at the boiler that the flow&return are actually reversed.

    Also check no water coming from condenate trap drain when boiler is cold, you may have to disconnect the drain somewhere to observe this, watch it for good few minutes because some of these traps discharge the water in bursts of 1/2 a litre or so at the time and are not continuous.


  • Registered Users, Registered Users 2 Posts: 12,839 ✭✭✭✭Dtp1979


    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.


  • Registered Users Posts: 200 ✭✭Paullimerick


    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.


  • Registered Users, Registered Users 2 Posts: 3,960 ✭✭✭jimf


    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


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  • Registered Users Posts: 124 ✭✭traume


    John.G wrote: »
    A few queries;

    Where is the pressure gauge located? (eg ground floor etc)
    Where is the EV located?
    What is the capacity of the EV.
    What was the EV pre charge pressure?
    What was/is the EV filling pressure? (cold)

    Regarding "Return and feed pipes on the boiler are mixed up", if they were then the boiler stat would be measuring the return temp and the actual flow temp would have been anything from 10C to 25C higher, wonder what effect the reversed flow has on a condensing boiler re corrosion.
    I would check at the boiler that the flow&return are actually reversed.

    Also check no water coming from condenate trap drain when boiler is cold, you may have to disconnect the drain somewhere to observe this, watch it for good few minutes because some of these traps discharge the water in bursts of 1/2 a litre or so at the time and are not continuous.

    Feed pipe comes from the attic, then down in the 1st floor in the hotpress I have Valve and after the valve pressure gauge. Under the valve there is a splitter where one pipe goes to the E.Vessel, return from radiators and then pipe goes straight in the floor and back to the boiler.

    I'm not sure what EV is, if you mean total system then I know that I have 11 radiators.

    Pressure does not change cold/hot. It is the same all the time but drops only if cold. I previously left boiler running for 3 hours and pressure stayed the same, once system cooled down pressure started to drop until 0 bars.

    Last night I pressurized the system to 1.5bar.

    I have not seen any water coming out of the condensate pipe on the boiler.


  • 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.
    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.


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭John.G


    EV is the expansion vessel.


  • 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.


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭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.


  • 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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  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭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.


  • 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?


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭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.


  • 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.


  • Registered Users, Registered Users 2 Posts: 3,559 ✭✭✭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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