JohnA Posted November 17, 2006 Share Posted November 17, 2006 I'm worried that the pressure keeps going up when CH is on, what is the max safe pressure, that sort of thing. It needs a bit refilling every few days when it works hard, so that can't be good, can it? Link to comment Share on other sites More sharing options...
far Posted November 17, 2006 Share Posted November 17, 2006 Trigs the Don when it comes to this kinda stuff - i'm sure he will be along shortly to share some wisdom Link to comment Share on other sites More sharing options...
JohnA Posted November 17, 2006 Author Share Posted November 17, 2006 Fingers crossed. I wouldn't want to call a jackass 'expert' who will do nothing but open the cover, pretend to be doing a 'service' and charge me for the privilege. The boiler is only 4 years old, it's Bosch, hasn't been abused, so it can't have gone wrong FFS... Any serious help welcome Link to comment Share on other sites More sharing options...
far Posted November 17, 2006 Share Posted November 17, 2006 Trig is from Kent as well - maybe try pm'ing him. I know what you mean about plumbing and stuff, theres so many cowboys out there. Maybe try http://www.vetted.com Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 17, 2006 Share Posted November 17, 2006 I'm worried that the pressure keeps going up when CH is on, what is the max safe pressure, that sort of thing. It needs a bit refilling every few days when it works hard, so that can't be good, can it? I have a Supra Aerotop owning customer who is a "plumber to the stars" in London, he's been most helpful to me, I'll try and find his e-mail address for you. I think he'll advise none A list people, too, as I am most definitely not one of those Link to comment Share on other sites More sharing options...
Havard Posted November 17, 2006 Share Posted November 17, 2006 John - pm me if you want a chat. Believe it or not the avarage life expectancy of a combi boiler is now 5 years. I used to sell them a couple of years ago and only got mine last Christmas. If you're losing pressure it is either a small leak on your system or a crack in the heat exchanger. How ofter are you filling the system up.? H. Sorry - misread the first post - might be the pressure vessel in the unit has lost its charge. Your safety valve will be set at 3 Bar usually. Once this opens you will loose pressure and when the system cools the boiler will not work until you put more water in. H. Link to comment Share on other sites More sharing options...
JohnA Posted November 17, 2006 Author Share Posted November 17, 2006 PM sent My main concern is that pressure keeps rising and rising when the CH is working. When it's just working for hot water it's fine. I suspect that something is amiss, but don't know enough about the workings inside. Link to comment Share on other sites More sharing options...
JohnA Posted November 17, 2006 Author Share Posted November 17, 2006 After some investigations and talking to Havard over the phone, I now know that my expansion vessel needs recharging. Live and learn - wasn't even aware I had a vessel, let alone it's got a tyre valve and I can check it with a tyre gauge. After calling a couple of local Bosch 'specialists' I discovered that they really don't like people requesting for their vessels to be recharged. Oh no, they want to send a rookie for initial 'investigation' (£65+vat) and then arrange for parts/more visits/whatever. One even pretended the line went bad right after I mentioned the word 'vessel'. They're all booked for weeks as well. Nice job to be doing, eh? Link to comment Share on other sites More sharing options...
bromy Posted November 17, 2006 Share Posted November 17, 2006 Get the old bike pump out:) Link to comment Share on other sites More sharing options...
JohnA Posted November 17, 2006 Author Share Posted November 17, 2006 Nah, apparently the whole boiler has to be drained and who knows what else. It's not as simple as topping up the airpressure - if only... Link to comment Share on other sites More sharing options...
RIJ8631 Posted November 18, 2006 Share Posted November 18, 2006 Its very easy to pressurise the expansion vessel. 1. Depressurise boiler by using the 3bar pressure release valve. (usually a valve inside the boiler with a red cap - turn it until the pressure on the gauge reads 0.) 2. Identify the ch expansion vessel ( either a squarish red vessel in the boiler or a round vessel down the back of the boiler) 3. Using a foot pump (by hand -not feet) pump up the vessel until you have approx 10psi - 14psi (check with a digital tyre pressure gauge) 4. Then repressurise boiler back to 1-1.5 bars of pressure. Its really as easy as that and save yourself £70 -£100 callout. One thing is if the 3b PRV has been running outside for some time than it may need to be replaced. cheers Ian Link to comment Share on other sites More sharing options...
Vicky Posted November 18, 2006 Share Posted November 18, 2006 The £65+ charge by worcester is actually really good value, as they then repair and service the boiler and warranty it for another year. Link to comment Share on other sites More sharing options...
JohnA Posted November 19, 2006 Author Share Posted November 19, 2006 Its very easy to pressurise the expansion vessel. 1. Depressurise boiler by using the 3bar pressure release valve. (usually a valve inside the boiler with a red cap - turn it until the pressure on the gauge reads 0.) 2. Identify the ch expansion vessel ( either a squarish red vessel in the boiler or a round vessel down the back of the boiler) 3. Using a foot pump (by hand -not feet) pump up the vessel until you have approx 10psi - 14psi (check with a digital tyre pressure gauge) 4. Then re-pressurise boiler back to 1-1.5 bars of pressure. Its really as easy as that and save yourself £70 -£100 callout. One thing is if the 3b PRV has been running outside for some time than it may need to be replaced. cheers Ian Thanks for the advice mate, I found the PRV, emptied the boiler, re-pressurised the vessel at 14psi, but when I let the water back, it lost all pressure within 5-10seconds, looks like the valve wouldn't work anymore. For a while I thought I'd be stuck with no hot water and no CH in very cold days! Necessity is the mother of invention, so I reckoned that being a valve it must have sealing surfaces that might be contaminated. So I turned it off and on a couple of dozen times - and YES it started leaking less. Now it looks tight enough to be of some use again. If it hasn't lost any pressure by tomorrow, it's probably fixed. How is this PRV meant to work? Mine has a red knob which only turns counter-clockwise and then it clicks. It is meant to move in an out as well? Link to comment Share on other sites More sharing options...
RIJ8631 Posted November 19, 2006 Share Posted November 19, 2006 what can happen if it has been passing for sometime ,is that the face to face surfaces can get a build up (contaminated), so the faces dont close tight any longer. If the pressure in the ch system rises over 3bar then the faces open and release the excess pressure -but should close off tight once pressure has dropped. If you have access to the blowoff pipe outside -then tie a poly bag onto it, and if it fills and you pressure continues to drop,then you may have a problem with the prv. cheers ian Link to comment Share on other sites More sharing options...
RIJ8631 Posted November 19, 2006 Share Posted November 19, 2006 How is this PRV meant to work? Mine has a red knob which only turns counter-clockwise and then it clicks. It is meant to move in an out as well? They usually are spring loaded, ie it returns to the closed position when released. If you do have a problem with the prv "its not the biggest job in the world to fix" Let me know if problem of losing pressure continues cheers Ian Link to comment Share on other sites More sharing options...
JohnA Posted November 19, 2006 Author Share Posted November 19, 2006 what can happen if it has been passing for sometime ,is that the face to face surfaces can get a build up (contaminated), so the faces dont close tight any longer. Yeah, that's what happened here probably. First time I manually discharched it, nothing came back as it should. After a few on/off cycles the sealing improved. Gave me a fright alright. ... If you have access to the blowoff pipe outside -then tie a poly bag onto it, and if it fills and you pressure continues to drop,then you may have a problem with the prv. Yeah, I've set a canister under the discharge pipe and followed the whole story. After the saga was over, the colour of the water was not yellowish anymore, it was tap water. Another injection of Fernox is in store soon. How hard is it to change this valve? I don't trust it. Link to comment Share on other sites More sharing options...
RIJ8631 Posted November 21, 2006 Share Posted November 21, 2006 JohnA, what is the latest news everything been ok or does problem still exist? let me know if i can help any further cheers ian Link to comment Share on other sites More sharing options...
JohnA Posted November 22, 2006 Author Share Posted November 22, 2006 Thanks to the instructions (from an automotive forum!!) I managed to set the boiler right. It all sounds a bit daunting for an ordinary Joe: Drain the boiler, pressurise the vessel, release the pressure valve, repressurise boiler etc. In fact (as I suspected) it's a piece of piss if one has a bare minimum of mechanical abilities, and knows the procedure and what the parts look like. Thankfully Bosch have some useful online PDFs. Armed with the insider knowledge from the members here I managed to fix it myself. Well chuffed. Thanks guys, I owe you one:d Link to comment Share on other sites More sharing options...
Havard Posted November 22, 2006 Share Posted November 22, 2006 Well done John. How much to fix mine next time it goes wrong.? I know how to fix it but just can't be arsed:) H. Link to comment Share on other sites More sharing options...
JohnA Posted November 22, 2006 Author Share Posted November 22, 2006 Without the instructions from Ian (RIJ8631) I would be stuck. If someone 'expert' were to come and get paid to disconnect and unhung the boiler I'd reluctantly agree, although I'd suspect 'rogue traders' bull. Even on the A1 forum (CH help) they are pretty hazy and evasive in their answers sometimes. Hey, it's a booming trade! Link to comment Share on other sites More sharing options...
RIJ8631 Posted November 23, 2006 Share Posted November 23, 2006 Glad to hear all is working well - proper job. Only allowed to help technically with non gas related jobs. But glad to be of help cheers ian Link to comment Share on other sites More sharing options...
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