Worcester Bosch Boiler Pressure Problems

Discussion in 'Plumbers' Talk' started by jsaipe, Dec 7, 2013.

  1. Jitender

    Jitender Screwfix Select

    Those Worcester Bosch boilers have an integral filling loop. There is a special key that needs to be inserted into it (this is attached to the removable tray). Turing the black handle will have no effect, unless the key is inserted and 'unlocked' There is a padlock symbol to indicate the locked and unlocked position.

    In either case its worth having a utensil under the boiler to catch any water, when doing this as its so fiddly.

    upload_2015-1-3_19-3-21.jpeg
     
  2. Deb1515

    Deb1515 New Member

    :):):)Yr a very smart man and I love you, I bought black turn of tap for flexi hose as mine was missing, put it on turn valve inside of as it must have been slipping extra water like you said, bled rads it took it straight down to 1.5 bar.
    Yr amazing, thanks so much. You have a great new year and its a pleasure to have chatted with you.

    Debs x
     
  3. Mikethepike

    Mikethepike New Member

    I'm new to this forum so bear with me. I'm having boiler problem similar to above.Does there come a point when we give up and buy new? I have an Ariston less than 6 years old. Pressure is high at 3 or more bar when running and never below 2.5 when cold/off. Dripping pipe outside. Three items have been replaced to no avail - the filling loop, pressure relief valve and replaced pressure vessel ( the big red tomato looking thing). last suggestion is to replace the expansion vessel. But the engineer does not promise success even then. This is good money after bad. Looking to probably replace boiler entirely, two suppliers tut tut at Ariston, my original supplier and maintenance engineer and one new supplier will use Worcester Bosch and the other Alpha - 30kW.
     
  4. Deb1515

    Deb1515 New Member

    Hello

    Did you read the notes about mine and what I did?
    Same thing wrong but my inlet cold water supply wasn't turned off fully which was releasing water slowly making the gauge go up. I bled rads after and it was fine.
    Bought new plastic tap to turn water off and on, have you bled rads? Does the gauge go down when u do it?
     
  5. Mikethepike

    Mikethepike New Member

    Thanks Deb. Have re-read and think I understand. I'll take a look tomorrow if I get time.
     
  6. Deb1515

    Deb1515 New Member

    Ok huni x
     
  7. I dunno - Debs fixes her boiler and now thinks she's an expert :rolleyes:.

    (Er, Mike, have you tried what she said...? :oops: )

    :)


    Mike, the dripping pipe outside is almost certainly your safety discharge pipe - it releases excess pressure when your boiler hits around 3 bar (which it shouldn't normally). The thing that releases this pressure is - as I guess you know - the pressure release valve. These fellows are prone to keep on leaking once they are activated, but a new one (which you have) should really stop dripping pretty much once the pressure falls below, ooh, 2.5 bar.

    That fact that your system pressure doesn't drop below 2.5bar when it's cold suggests that your expansion vessel is working ok.

    You've had various parts replaced and no doubt the service fellow took the pressure back down to the normal 1bar-ish each time? And yet the pressure climbs upwards each time to 3 bar?

    As Deb says (ok, ok, she is the expert... :)), the first thing to check is the filling loop - is the 'top-up' system letting mains water slowly into your boiler's sealed system? Simple test - remove the filling loop. Do you still have this problem?

    (I'm guessing you ain't going to be as lucky as that, since it's the obvious thing for a service guy to check first - if he hasn't done that, he needs a through spanking.)

    Ok, since it doesn't look like an expansion vessel problem (with a faulty exp vess you would have to manually top up the system pressure yourself each time the pressure drops to near zero - you are NOT having to do this? The pressure doesn't fall below 2.5bar?)

    In which case, the increasing water pressure is coming from somewhere else - from the mains water through another source. Not many options here - one is a faulty heat exchanger, one that has developed a leak inside and allows mains pressure to seep through to the 'system' side.

    Another potential is if your boiler is not a 'combi' type, but a system boiler - ie: it heats up a hot water storage system of some type? It would have to be a 'sealed' pressurised system like a Megaflow, and possibly the heating coil inside this hot cylinder has developed a leak allowing the hot stored mains pressure water to seep into the boiler's system.

    I can't think of anything else.

    So, check the obvious first - remove that filling loop, reduce the system pressure by opening a radiator bleed valve - get it down to chust above 1 bar - and see what happens. Keep running it. And report back, please.
     
    Last edited by a moderator: Jan 10, 2015
  8. Deb1515

    Deb1515 New Member

    Lol, that's why I said read and what I did, no! You're the expert huni x
     
  9. Tee-hee.

    Alas, no - I know a few things about some boilers - gained from bitter experience :oops:


    Mike, I'd strongly suggest starting a new thread on your issue - head it up with the boiler's make & model, and the basic fault - 'constant high pressure...' - and repeat what you said in your first post. Also add what type of system you have - 'combi' or 'system'' (I'm guessing the latter since you mention two red vessels?)

    That way the plumbers will be more likely to see your plight.
     
    Vin likes this.
  10. Mikethepike

    Mikethepike New Member

    ThaNKS.
     
  11. Mikethepike

    Mikethepike New Member

    Thank you all. I am now 'going in' and will report back.
    As a PS, my engineer was thinking of changing the secondary heat exchanger next, but without guaranteeing that will deal with the problem.
     
  12. You're welCOME.
     
  13. Chloe520

    Chloe520 New Member

    I have a Worcester Bosch Greenstar 3.0CDi where the pressure dropped to zero if the heating was on or off. The problem remained after pumping air into the vessel.

    We drained the system and replaced the vessel but, the problem of the pressure drop to the bottom on the dial continues when the heating is off. I assumed that the new vessel comes readily charged and so did not pump air into it.

    There is nothing coming out of the copper pipe outside but, we placed the end of the plastic pipe (that goes outside and down into a plastic drain pipe) into a bowl instead and this filled up with water, stopping when the pressure had dropped. I thought this was the condensation pipe but it is clearly where the water is going and even when the system is off, cold water drains out until the pressure is at the bottom.

    We also have the boiler 'firing up' briefly at intervals with water movement and 'gurgling' when the heating is switched off. Probably not related?
     
  14. Chloe - worth starting anew thread chust for yersel'...

    But, anyways, the copper pipe you mention is almost certainly the safety discharge pipe (and it would have been good news had this been the one dripping...) and the plastic one is very likely to be the condensate pipe -which will glug and drip at regular intervals when the boiler is running, but should stop some time after the boiler is off again.

    The fact that this plastic pipe continues to let out water even when the boiler has been off for some time suggests an internal leak in your boiler - such as a faulty heat exchanger. System water is getting out and entering the combustion chamber and hence draining out through the condensate route.

    Bear in mind that this plastic pipe will have water coming out at times when the boiler is running normally, and this could well carry on for a few minutes after the boiler has last switched off. But, if you are certain it is continuing to drip when the boiler is stone cold, and carries on doing so until the pressure reaches zero, then I suspect a leaking exchanger.

    That's a biggie... :(

    Others will be along and they might know of another - less painful - way for water to escape (eg a seal or summat). Fingers crossed.

    Meanwhile, could you start a new thread, please? It'll be more likely to receive responses than a long 'old' one.
     
  15. Mikethepike

    Mikethepike New Member

    Update. Not looking good.

    Turned system off yesterday, disconnected loop and drained some litres off a radiator to get pressure down to 1 bar. Turned system on and pressure crept up very slowly, loop still disconnected. System off overnight and came on by timer this a.m. Bar 2 at 8am. System went off by timer but I have turned it on again for heat and had a shower in the last hour. Pressure was about 2.3 but is slowly rising all the time. It is now about 10:40 and pressure is 2.5. Still drips outside - slowly earlier and now once every 6 or 7 seconds. Loop remains disconnected at one end.

    I have a combi boiler for heat and water. Ariston Combi A series (probably size 24), installed July 2009.
    As mentioned above, loop and pressure relief valve have been replaced followed by a new pressure vessel (large red bubble thingy), fitted to hot pipe outside of the boiler (apparently this saves the bother of dismantling the one inside and is meant to work the same). As also mentioned above, my service man suggests he could fit a secondary heat exchanger. ? Well, I had a go.

    I really am thinking of a new boiler. In which case do I start another thread? I'm getting differences of opinion re Worcester and my local engineer favours Alpha. Perhaps they have deals with suppliers.

    Regards
    Mike
     
  16. Hi Mike - and that's why it's worth a new thread; 3 different boilers on this one! :)

    Ok, you've disconnected the lop - so it ain't that. A shame...

    That does leave a component that shares both the system water and the mains water, and is allowing one to pass to t'other. And about the only thing I can think of is, indeed, the secondary heat exchanger (where the hot water for your taps is heated).

    Is it worth fixing? I dunno, I doubt it - but others will advise. It's bound to be a £200+ bill easily, I'd have thought.
     
  17. Mikethepike

    Mikethepike New Member

    Yes, 'about £300' is my quote. Spent nearly as much already. But thanks ever so much.

    I will start a thread on makes later on.
     
  18. Chloe520

    Chloe520 New Member


    QUOTE="Chloe520, post: 1325074, member: 127321 Not sure if I have done this right but I have started a new thread.
     
  19. simaddox@btinternet

    simaddox@btinternet New Member

    I know you'd like to start a new thread, but I'm a new Member and I don't know how to do that! Besides my problem is all about Worcester Bosch and water pressure.

    Last April we had a new Worcester Ri high efficiency gas heat only boiler fitted by a WB approved installer (who has been brilliant and who we cannot fault). As the boiler is in the loft, there is not enough head pressure to run on a gravity basis, so the entire heating system is pressurised but only to the existing head pressure. This has been done via a 15 litre expansion vessel and guage sited in the airing cupboard.

    The installation was completed on the 14th March 2014 and by the 22nd I had noticed that the pressure was fluctuating between 2bar (when running) and 0.7bar (when cold). Then on the 28th March the cold pressure dropped to 0.3bar and the boiler failed to fire. I replenished the water pressure by opening the inlet tap for just a few seconds. The pressure went up and the boiler fired.

    This cycle was repeated at an interval of (on average) 22 days until I turned the heating off at the beginning of June.

    When the heating system was restarted in September with a reduced boiler temperature, it was fine for nearly two months, then when the temperature was turned up for the colder weather, the cycle resumed. It is now running on an exact 16 days cycle. The hot pressure stays absolutely static at 2 bar and the cold pressure stands at 1.5 bar for a fortnight - then the cold pressure goes right down and the boiler fails to fire. Now I know it will happen after 15 days, I am tempted to refresh the pressure on the evening of the 15th day rather than wake to a cold house in the morning.

    The Engineers who fitted the system have been brilliant. They have been out numerous times and have checked everything and have fitted a larger expansion tank. However the problem continues. They felt that there must be a leak in the radiator system somewhere so filled it with a leak sealant. As there is no visible sign of a leak, they now want to look under the downstairs floors. However, we are reluctant to do this as we've just had new carpets, wooden floor and Amtico covering in the kitchen.

    Any ideas?
     

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