Paul-H Posted November 6, 2009 Share Posted November 6, 2009 Hi Guys Anyone out there a qualified plumber/heating engineer. Got a problem with mine and looking for a bit of advice. The problem is the radiators do not get as hot as I think they should all bar one have stats on and they are all fully open, the one without a stat is hardly warm at all. The Boiler an 80,000BTU unit has a dial on front marked 1 to 9, if I turn it above 6 it starts hammering. The Boiler, Tank, Pump, Timer was installed new in February this year. I have the installer comming back to look but anyone know what it might be so I can tell if he is trying to fob me off with an expensive repair when it is something he should have done during the boiler intall. Thanks for any help Paul Link to post Share on other sites More sharing options...
Chameleon Posted November 6, 2009 Share Posted November 6, 2009 Well the hammering is an easy fix. It is usually down to a certain flow/radiator thermostat combination usually cause by one of them being fitted in reverse (they are sorta directional) all you do s tweak any one of them to adjust the systems flow. Can't really help with the lack of heat though. Are there any airlocks in the system? Have you bled all the radiators? I assume it Is a new system? If not, how old is it or when was it last serviced? Have you checked the pressure in it? Is the burner ok? How hot is your hot water? Link to post Share on other sites More sharing options...
Kenton Posted November 6, 2009 Share Posted November 6, 2009 NOT a plumber. But have installed 2 complete central heating systems in this and a previous house (except connecting to mains gas) Sounds like air in the system - just as suggested above. bleed all radiators with no water pumping through - starting with the lowest. A simple job (even my wife can do it) just open the bleed valve slightly until no more air escapes and water dribbles out. then turn on the system. Check that the pump is actually pumping round - it may be a 2 or 3 speed one - if so change the speed and listen for a change in flow of water. If your boiler is "bumping" the this is either air in the boiler or the water is being heated too high (the water is not being pumped through fast enough) and it is boiling the water. If air fix as above otherwise (if pump is running ok) just turn down the boiler. There should be one rad without closed valves or more usual a bypass route for the water to the boiler. Sometimes this is fitted with a valve for "balancing" - ensure that it is not fully closed. If all that solves the problem - great, you have saved about ??80 call out + ??80 to do a 10 minute job. If it doesn't ask your bank manager for a loan. Sometimes pumps fail - they are simple to replace but these days with all the nanny state regulations require a plumber with electrical qualifications. They usually fail when first started at the winter "turn on" due to residues clogging the mechanism. The same applies to diverter valves used to switch between central heating and water heating. Again easy to replace but again you have to find a plumber with the fully paid up "union card". Whatever you do don't mess with the boiler (eg taking the cover off) especially not the gas supply or burner. Anyway that should still be under warranty. Link to post Share on other sites More sharing options...
RMweb Gold Taz Posted November 6, 2009 RMweb Gold Share Posted November 6, 2009 Is your boiler a combi-boiler or not? Combi-boilers work on a presurised system circuit and if this was too low it could explain some of the symptoms you are describing. If it is a combi-boiler their will be a pressure gauge somewhere on it and the ability to top up the system from the mains. Link to post Share on other sites More sharing options...
Paul-H Posted November 6, 2009 Author Share Posted November 6, 2009 Thanks for the replies guys Air in the rads was the first thing I checked and all had no air. Hot water is hot and central heating pipe from the diverter valve is almost too hot to touch. The bathroom rad which is the one without the stat is also for some reason the first on the system when as I understand it it should be the last is the one not getting much heat in it even though the pipe only a foot away is too hot to touch. Boiler, Tank, Pump, Diverter Timer and stat were all new in February, Rads and pipework is OLD. The Rad stats have all been in place for a few years now (5ish) so I don't think thats the problem. Its not a Combi Boiler its an Alpha CD24R (which you are all now going to tell me is rubbish) but its in so nothing I can do about it now LOL. Installer said it sounds like a blockage does that sound right. Thanks Paul Link to post Share on other sites More sharing options...
Nortonian Posted November 6, 2009 Share Posted November 6, 2009 Hi Paul, We may need a litle more info as we are not on site to help diagnose your problems. I agree with Chameleon over the hammering, it could be a thermostatic valve fitted the wrong way round although, this should of shown up well before now if fitted in February. Alternatively, you could have an airlock. First thing is to turn the heating off, then check/bleed each radiator to see if all is full. Then close all the thermo radiator valves and leave the non thermo valve radiator open. Turn the heating on and wait until the radiator gets hot. If you still have hammering, then it could still be an airlock and the sound is actually the boiler `kettling` !. This means the hot water in the boiler is not being pumped around the system, due to an airlock somewhere and literally boiling. Again we need more info before continuing to the next stage. If the boiler/rad works okay at this stage, then open the other radiators one at a time until hot. Never bleed a radiator when the pump is running !. Is your system a fully pumped type, ie, a three way valve in the cylinder cupboard ?. If not, then chances are you are a basic gravity fed. If fully pumped, then checking the valve opens properly betwen heating and/or hot water needs to be confirmed, also if this type, an automatic air seperator in the pipework next to the pump should displace the air to the tank in the loft.Set to water only first to shift any air then the heating only. If you are the basic gravity type, then you may need to force mains cold water into you c/h sytem via the tanks vent,ie, the 22mm pipe to force the airlock out into the tanks cold feed,ie,15mm pipe, at the bottom of the small tank,ie, working the opposite way to normal. In both cases, make sure there is water in the tank in the first instance, even before you vent any radiators as the hammering could just be that the ballvalve has got stuck closed on the small cold feed tank, and this is why the boiler is hammering. NO FLIPPIN WATER !!!!!. Come back to us on this thread and we will see if we can be more of a help. Regards Ian Link to post Share on other sites More sharing options...
Nortonian Posted November 6, 2009 Share Posted November 6, 2009 Hi paul, in the time it has taken me to write that last reply, I see you have had others. So, still check the water level in the tank, and close the valves as I have said and open up one at a time. Let us know how you get on Ian Link to post Share on other sites More sharing options...
Kenton Posted November 6, 2009 Share Posted November 6, 2009 The bathroom rad which is the one without the stat is also for some reason the first on the system when as I understand it it should be the last is the one not getting much heat in it even though the pipe only a foot away is too hot to touch. It is possible that the bathroom rad is on the "water circuit" this is done to keep condensation out of the bathroom. If it is, than it will generally only heat up when the water is being heated. When off the CH thermostat and when it is only heating water (summer use) does the bathroom rad heat up? As the other rads are heating when on CH then we should be able to assume that there is no block. Just a word of warning - one of our neighbours got a "professional" plumber in to fix a problem with residues in the system. The plumber connected a pump to the drain valve on the system and pumped water into it. The result was a blown boiler!! He had forgotten to disconnect it from the system. A standard gravity fed boiler cannot take such pressure. A long legal battle ensued ending in the small claims court. The plumber said he had disconnected it and that the fault was a old damaged boiler. On word against anothers. Installer said it sounds like a blockage does that sound right. Yes, but then it is his fault, as he should have flushed the whole system out before/at installation. He should then have added the 'softener' to the tank to prevent residue build up. Are you in a hard water area? When you bleed the rads does the water that comes out appear black and gritty. Link to post Share on other sites More sharing options...
Paul-H Posted November 6, 2009 Author Share Posted November 6, 2009 Are you in a hard water area? When you bleed the rads does the water that comes out appear black and gritty. Hi I am in Kent so yes its a hard water area, the water from the rads when I blead them is clear. Link to post Share on other sites More sharing options...
Paul-H Posted November 6, 2009 Author Share Posted November 6, 2009 Hi Guys Thanks for all the help and advice, I will try some of the suggestions tomorrow and report back. Link to post Share on other sites More sharing options...
Paul-H Posted November 9, 2009 Author Share Posted November 9, 2009 Hi Guys Had the Plumber out yesterday and he foung the in-line filter to the boiler fas blacked with rubbish, he cleaned it and its all back working fine. Going to get him back in a couple of weeks to do a full pressure flush to clean the whole sysem out. Thanks for the help guys Paul Link to post Share on other sites More sharing options...
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