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  • FIRST POST
    • BillG100
    • By BillG100 10th Dec 17, 5:32 PM
    • 30Posts
    • 8Thanks
    BillG100
    Vaillant Ecotec boiler losing pressure intermittently
    • #1
    • 10th Dec 17, 5:32 PM
    Vaillant Ecotec boiler losing pressure intermittently 10th Dec 17 at 5:32 PM
    Hi,

    My Vaillant Ecotec boiler is losing pressure intermittently but quickly and only when it is switched off! What happens is...

    1) The boiler runs fine for a period of time which could be a few days or weeks and the pressure is reasonably constant (varies about 10% to 15% with the temperature)

    2) Boiler loses pressure quickly during the overnight period when heating / water is off

    3) Boiler won't restart and an f.75 error code is displayed

    4) I add some water to re-pressurise and it starts again without a problem

    5) The cycle (steps 1 to 4) then repeat

    The expansion vessel has been re-pressurised. There's no sign of a leak and it would have to be an odd one to behave in this way. The pressure gauge reading appears to be correct.

    I'm at a loss. Any ideas?
Page 3
    • mossy007
    • By mossy007 8th Feb 18, 1:38 PM
    • 8 Posts
    • 1 Thanks
    mossy007
    So you have now located your leaks? Are these the culprits for the pressure loss?
    • BillG100
    • By BillG100 8th Feb 18, 4:40 PM
    • 30 Posts
    • 8 Thanks
    BillG100
    So you have now located your leaks? Are these the culprits for the pressure loss?
    Originally posted by mossy007
    No. The leaks seems to be a symptom rather than the cause. To get SO many leaks in a such a short period seems odd. That's why I wonder whether it is something to do with the underfloor heating zone valve. I em'd Polypipe earlier today but they've not replied yet.
    • AmateurLearner
    • By AmateurLearner 14th Feb 18, 11:14 AM
    • 1 Posts
    • 0 Thanks
    AmateurLearner
    pressure loss
    Valliant combi user here! Same issues - Ive stumbled upon possibility of frozen condensate pipe outside causing the boiler to shutdown and therefore lose pressure... anyone else?
    • BillG100
    • By BillG100 15th Feb 18, 6:51 PM
    • 30 Posts
    • 8 Thanks
    BillG100
    Valliant combi user here! Same issues - Ive stumbled upon possibility of frozen condensate pipe outside causing the boiler to shutdown and therefore lose pressure... anyone else?
    Originally posted by AmateurLearner
    We used to have the condensate pipe running outside but got it re-routed internally a number of years ago. I'm not a plumber / heating engineer but to me it is utterly barking that in a country 50 degrees north it is even legal to run them outside! However it hasn't been particularly cold recently and the rapidly strengthening sun also means freezing becomes less of an issue by mid Feb. Also regardless of the weather I'd be surprised if your condensate pipe has frozen because you would have water backing up and spilling out.
    • mossy007
    • By mossy007 20th Feb 18, 9:02 AM
    • 8 Posts
    • 1 Thanks
    mossy007
    No. The leaks seems to be a symptom rather than the cause. To get SO many leaks in a such a short period seems odd. That's why I wonder whether it is something to do with the underfloor heating zone valve. I em'd Polypipe earlier today but they've not replied yet.
    Originally posted by BillG100
    Quick update on my intermittent pressure loss. Heating engineer been out and the UFH was isolated to boiler and pressure tested overnight using a pressure gauge connected to return of manifold and there was slight pressure loss. There was no pressure loss from the CH side. Engineer powerflushed the UFH and refilled and balanced to sort out any potential air locks. Leak sealer was fed into the UFH flow and inhibitor was fed into the CH flow to iron out any potential small leaks. The system has been now run for 13 days and no pressure loss so far been running on 1.5bar constant. Billg100 maybe you can try this. The zone valve was fine.
    • BillG100
    • By BillG100 20th Feb 18, 11:12 AM
    • 30 Posts
    • 8 Thanks
    BillG100
    Quick update on my intermittent pressure loss. Heating engineer been out and the UFH was isolated to boiler and pressure tested overnight using a pressure gauge connected to return of manifold and there was slight pressure loss. There was no pressure loss from the CH side. Engineer powerflushed the UFH and refilled and balanced to sort out any potential air locks. Leak sealer was fed into the UFH flow and inhibitor was fed into the CH flow to iron out any potential small leaks. The system has been now run for 13 days and no pressure loss so far been running on 1.5bar constant. Billg100 maybe you can try this. The zone valve was fine.
    Originally posted by mossy007
    Quick update from me....

    We got a thermal imaging camera to check out the UFH. The circuits could be seen clearly and there was NO sign of a leak. That gave me more leverage with BG who had been pointing the finger of blame at the UFH (perhaps because they don't cover it on their policy?). Eventually another small leak was identified and fixed in the CH system. That was also about 13 days ago and since then our boiler has been running consistently at 1.1 bar when it is off to 1.5 bar when it is on. We're keeping our fingers crossed now - especially with the Siberian blast expected next week!

    Don't want to sound overly critical of BG but the overall level of service has left a lot to be desired IMO. Individually all the guys who have been round were pleasant and sounded knowledgeable. On the other hand suggesting the UFH was the cause of the problems struck me as being a tad lazy at best.
    • Ruski
    • By Ruski 20th Feb 18, 12:51 PM
    • 1,579 Posts
    • 928 Thanks
    Ruski
    Where was the latest leak that you found?

    Russ
    Perfection takes time: don't expect miracles in a day
    • BillG100
    • By BillG100 20th Feb 18, 3:07 PM
    • 30 Posts
    • 8 Thanks
    BillG100
    Where was the latest leak that you found?

    Russ
    Originally posted by Ruski
    On a valve o-ring.
    • mossy007
    • By mossy007 11th Mar 18, 2:37 PM
    • 8 Posts
    • 1 Thanks
    mossy007
    Quick update from me....

    We got a thermal imaging camera to check out the UFH. The circuits could be seen clearly and there was NO sign of a leak. That gave me more leverage with BG who had been pointing the finger of blame at the UFH (perhaps because they don't cover it on their policy?). Eventually another small leak was identified and fixed in the CH system. That was also about 13 days ago and since then our boiler has been running consistently at 1.1 bar when it is off to 1.5 bar when it is on. We're keeping our fingers crossed now - especially with the Siberian blast expected next week!


    Don't want to sound overly critical of BG but the overall level of service has left a lot to be desired IMO. Individually all the guys who have been round were pleasant and sounded knowledgeable. On the other hand suggesting the UFH was the cause of the problems struck me as being a tad lazy at best.
    Originally posted by BillG100




















    the

    Great News! Might invest in one of these flir cameras (thermal imaging) that attach at the end of you iphone. Had a plumber round with and worked really well. Save a lot of hassle if anything else goes wrong in the future.
    • BillG100
    • By BillG100 3rd Apr 18, 6:52 PM
    • 30 Posts
    • 8 Thanks
    BillG100
    The boiler has maintained pressure for almost two months so I hope the problems are resolved. I'll briefly summarise the lessons learnt for anyone who has similar problems in the future and finds this thread.

    1) Not much diagnosis was done by BG. They seemed to rely on swapping out components in the hope that would fix things.

    2) Don't be fobbed off! BG were keen to point the finger of blame at the underfloor heating system which isn't covered by the insurance we have with them. Eventually I used a thermal imaging camera on the underfloor heating and that strongly indicated there were no problems.

    3) Not 100% sure about what the actual cause was. Both valves on the bathroom towel ring had slow leaks. However the heat exchanger on the Vaillant was also changed and another two small leaks were identified during the period. One of those was in the loft near the boiler and it appeared shortly after an engineer had been poking around.

    To end on a positive note my advice if you find yourself in a similar position is don't fear the worst!
    • Cisteria
    • By Cisteria 9th Apr 18, 3:29 PM
    • 1 Posts
    • 0 Thanks
    Cisteria
    Same problem here...
    Really glad I found this thread as we have the same problem with our Vaillant EcoTec (7 years old). Rapidly losing pressure but the plumber can't find any signs of leakage or extraction. This thread has hopefully saved me some trouble. I'm going to be checking drain pipe daily for purges of the siphonic trap first.

    Am I correct in understanding that in the end it was the leak sealant that solved the problem?
    • BillG100
    • By BillG100 9th Apr 18, 7:09 PM
    • 30 Posts
    • 8 Thanks
    BillG100

    Am I correct in understanding that in the end it was the leak sealant that solved the problem?
    Originally posted by Cisteria
    Not in my case. No leak sealant was used. See my summary immediately above your post.
    • mossy007
    • By mossy007 24th Apr 18, 2:49 PM
    • 8 Posts
    • 1 Thanks
    mossy007
    Cisteria I used the leak sealer and believe or not it held for 2 months or so now so I am back to square one now losing pressure rapidly. I have heating engineer with thermal camera in on Thurs to check for leaks underfloor heating pipework. Will see what happens
    • irfanchaudhry
    • By irfanchaudhry 11th Aug 18, 9:34 AM
    • 1 Posts
    • 0 Thanks
    irfanchaudhry
    Vaillant boiler loosing pressure no sign of leak
    On a valve o-ring.
    Originally posted by BillG100

    Hi, I have exactly the same problem and the heat engineers are not able to find the cause. I am really going crazy. I loose about 0.1 bar over night. In my case there is no sign of a leak and I have gone around with a tissue to check valves. Was there any obvious sign of water where the o ring was damaged?
    Your help is appreciated,thank you.
    • BillG100
    • By BillG100 27th Aug 18, 5:06 PM
    • 30 Posts
    • 8 Thanks
    BillG100
    Hi, I have exactly the same problem and the heat engineers are not able to find the cause. I am really going crazy. I loose about 0.1 bar over night. In my case there is no sign of a leak and I have gone around with a tissue to check valves. Was there any obvious sign of water where the o ring was damaged?
    Your help is appreciated,thank you.
    Originally posted by irfanchaudhry
    There was no obvious sign of water where the o-ring was leaking.

    It sounds to me like you've reached the stage where they should send in the leak detection plumbers. One approach involves pumping an inert gas into the central heating system and then using a sniffer to detect where / if it is escaping.
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