harrycatcat1 Posted February 21, 2011 Report Share Posted February 21, 2011 My wife has just informed me that my daughters combi boiler produces hot water through the central heating radiators but she has no hot water through the taps or the shower This has worked ok up till today. Is there a simple answer or is it a combi boiler specialist job. Quote Link to comment Share on other sites More sharing options...
DSPUK Posted February 21, 2011 Report Share Posted February 21, 2011 NO and YES Quote Link to comment Share on other sites More sharing options...
Blackpowder Posted February 21, 2011 Report Share Posted February 21, 2011 When you say NO HOT WATER do you mean no water flows through the hot taps or does cold water flow from the hot taps, sort that out on here and you should not have long to wait for an answer. Blackpowder Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted February 21, 2011 Author Report Share Posted February 21, 2011 When you say NO HOT WATER do you mean no water flows through the hot taps or does cold water flow from the hot taps, sort that out on here and you should not have long to wait for an answer. Blackpowder Cold water flows through the hot taps and shower which is fed from the combi, thanks Quote Link to comment Share on other sites More sharing options...
vampire Posted February 21, 2011 Report Share Posted February 21, 2011 Heat exchanger/diaphram/just replace bits till it works,thats what most engineers do,if you have an ideal boiler,save your self some money and buy a new one now my boiler had your problem and £470 later it works and i am a plumber and my mates a gas engineer so did it cheap ended up replacing most of the bits and competely stripped it down and flushed system as well,wish i had just bought a new one as he suggested Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted February 21, 2011 Author Report Share Posted February 21, 2011 Heat exchanger/diaphram/just replace bits till it works,thats what most engineers do,if you have an ideal boiler,save your self some money and buy a new one now my boiler had your problem and £470 later it works and i am a plumber and my mates a gas engineer so did it cheap ended up replacing most of the bits and competely stripped it down and flushed system as well,wish i had just bought a new one as he suggested Thanks mate I appreciate the advice I don't know what make it is but it sounds as though its gona be expensive. Thanks for taking the time to answer Quote Link to comment Share on other sites More sharing options...
vampire Posted February 21, 2011 Report Share Posted February 21, 2011 The diaphram is about £6 and is a little bit of rubber that gets put under pressure then this pressure pushes out a switch that commands hot water and this switch does not always come all the way out,you could make it do it manually,but i wouldnt start mucking about unless you know what to do. The heat exchanger is like a mini rad that rads go through one side and hot water the other,these do get blocked,especailly if its a dirty system and no limescale fitted,cost for part about £100. Quote Link to comment Share on other sites More sharing options...
Medic1281 Posted February 21, 2011 Report Share Posted February 21, 2011 My wife has just informed me that my daughters combi boiler produces hot water through the central heating radiators but she has no hot water through the taps or the shower This has worked ok up till today. Is there a simple answer or is it a combi boiler specialist job. I don't know the name of the part but there is usually a motorised valve in the boiler that opens and closes to divert water either to the heating system or the hot water system. I had a similar problem and found it to be this. they aren't too expensive out of screwfix! Quote Link to comment Share on other sites More sharing options...
Canis Posted February 22, 2011 Report Share Posted February 22, 2011 Cold water flows through the hot taps and shower which is fed from the combi, thanks If you turn the central heating on via programmer and thermostat so that the heat is on, do you then get hot water from the tap ? if you do get hot water under these circumstances it is probably the differential pressure assembly/switch alternatively if the hot water remains unheated it is likely to be the diverter valve. Either which way, the work is fairly straightforward, with the manual that would have been left with the boiler describing fault diagnosis and removal and refitting of the faulty part. That said working on a boiler without gas safe accreditation is Illegal, EVEN ON YOUR OWN BOILER! While i have heard of people who repair their own boilers, when they dont have gas safe accreditation, I wouldn't advise it if you don't know what you are doing as if you get stuck a reputable accredited fitter would be under obligation to report the situation. the cost to repair your problem should be in the £50-150 range depending on exactly what is broken ! Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted February 22, 2011 Author Report Share Posted February 22, 2011 Thanks for everyones responses I am at work at the moment and they get mardy with folk ont tinternet, but I have since found out its a Saunier Duval boiler and my daughter has asked a plumber she knows to have a look at it this evening so I will let you know what he says, if anything. Thanks again. Quote Link to comment Share on other sites More sharing options...
iandl Posted February 22, 2011 Report Share Posted February 22, 2011 if you have hot radiators but no hot water or vice versa its generally the diverter valve ....usually a 1/2 hr fix ....take the boiler make and model no ...google it and you'll get someone local hopefully with spares .......parts usually around £60-80 depending on make Ian Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted February 22, 2011 Author Report Share Posted February 22, 2011 if you have hot radiators but no hot water or vice versa its generally the diverter valve ....usually a 1/2 hr fix ....take the boiler make and model no ...google it and you'll get someone local hopefully with spares .......parts usually around £60-80 depending on make Ian Cheers mate thanks, this site is an encyclopedia of knowledge and the folks on it make it just great Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 (edited) Heat exchanger/diaphram/just replace bits till it works,thats what most engineers do,if you have an ideal boiler,save your self some money and buy a new one now my boiler had your problem and £470 later it works and i am a plumber and my mates a gas engineer so did it cheap ended up replacing most of the bits and competely stripped it down and flushed system as well,wish i had just bought a new one as he suggested . silly answer Edited February 22, 2011 by myzeneye Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted February 22, 2011 Author Report Share Posted February 22, 2011 Chap just been and he says that as the boiler is 15+ years old it may pay to install a new one as the parts for it ( its a Saunier Duval) are expensive and because of its age it will not be as efficient/economical as a new one. My daughter remembers paying £180 + fitting a couple of years ago for a fan for the boiler. He is to price up a few parts and get back to her. What do you think about the new boiler idea as he has suggested a condensing boiler whatever that is? Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 If you turn the central heating on via programmer and thermostat so that the heat is on, do you then get hot water from the tap ? if you do get hot water under these circumstances it is probably the differential pressure assembly/switch alternatively if the hot water remains unheated it is likely to be the diverter valve. Either which way, the work is fairly straightforward, with the manual that would have been left with the boiler describing fault diagnosis and removal and refitting of the faulty part. That said working on a boiler without gas safe accreditation is Illegal, EVEN ON YOUR OWN BOILER! While i have heard of people who repair their own boilers, when they dont have gas safe accreditation, I wouldn't advise it if you don't know what you are doing as if you get stuck a reputable accredited fitter would be under obligation to report the situation. the cost to repair your problem should be in the £50-150 range depending on exactly what is broken ! not so...... its strongly not advised to work on any gas appliance if your not qualified, but believe it or not, in your own home, you can do what you like..its not "illegal" if however your are "working for gain" (quote gas regs)you must be qualified and a member of the governing body, ie*gas safe. Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 (edited) saunier duval are owned by glow worm, who are owned by vaillant...but unfortionaitly, they are a million miles away in build and quality to any vaillant....however, some saunier duval models are exact copies of some glow worm boilers, depends on model... let us know the model and we'l have a better idea... some combi's use a divertor valve set up and others use a flow switch and route the dhw a different way... let us know the model and we,can establish what youve got. if, it is a divertor valve, it likley to be either the diapraghm but could also be the micro switch which works in conjunction with it...its very easy to test to see if its either of them.... there are also a few pcb faults which can cause this same problem too... although at this stage i wouldnt be looking at them... also a whacked out ntc thermistor can give a similar problem.... not knowing what model you have, we'l assume it is a model with a divertor... a manual will help you imensly at this stage... take the front case of the boiler.. look for (usually) a brass valve which has a round head with approx 8 screws round the outside and a stainless steel push rod slightly poking out the middle of it...sometimes the rod will have a plastic cap on the end of it,somtimes its enclosed in a clamped on plastic housing for the micro switch.... get someone to turn on a hot tap... the push rod should extend out of the valve body and hit a micro switch... if it doesnt come out, the diapraghm is perished...there your problem... if it does come out and hit the switch but still no ignition, you can link out the two wires going to the switch, if the boiler fires up the micro switch is at fault.... if you still have no joy, well, you need to measure the resistance of the dhw thermistor... and yes, its kinda getting a little technical for a layman at this stage... call a reputable breakdown engineer in is probably best.. one last thing, if you can get dhw when the central heating is running, it can be a pcb fault, some boards have a sequence for c.h and a seperate set of soloniods on the baord for dhw...if the boiler is already lit for c.h demand and you can then get dhw when you open a tap, its likley that the baord has already gone through variuos parts of its ignition sequence and youve "bypassed" the normal electronic route the board follows for dhw demand...faulty board. if its none of the above and you have a flow switch as oposed to a divertor valve.... well the flow switch can be tested by checking the resistance with a multi meter, but more simply the two wires which go to it can be carfully linked out... if it fires, theres your fault....... parts for suanier duval are'nt expected to be on the shelf at part centre but they are available most of the time...i would expect a divertor diaphram to cost around £8-20, flow switch/sensor to cost around £ £30-40 and a pcb, well, could be from £80 to £180.... the details ive given here, are a very crude, simple methods of fault finding on this kind of problem..... before i personally replaced ANY part on a boiler, a quick check of resistance/voltage/continuety with a mulit meter would confirm the fault. whilst i would nver advise anyone to mess around with gas, this fault is on the water side of the boiler...ok, theres a few electrical bits and bobs, but common sense should prevail on this front... also, my point here is not strictly to instruct you to fix it your self, more to be aware that the fault can easily be found with some simple testing methods and to indicate where your engineer should be looking and the relavant things he should be looking at...rather then just fobbing you off with "naggghhh...its goosed love" FOR THE RECORD...... PEOPLE WHO THROW PARTS AT BOILERS TILL THEY WORK SHOULD LEAVE THEM ALONE AND STOP TAKING CASH OFF UNSUSPECTING NON THE WISER CUSTOMERS.. people like this give well trained reputable engineers a bad name. Edited February 22, 2011 by myzeneye Quote Link to comment Share on other sites More sharing options...
Martin2 Posted February 22, 2011 Report Share Posted February 22, 2011 Chap just been and he says that as the boiler is 15+ years old it may pay to install a new one as the parts for it ( its a Saunier Duval) are expensive and because of its age it will not be as efficient/economical as a new one. My daughter remembers paying £180 + fitting a couple of years ago for a fan for the boiler. He is to price up a few parts and get back to her. What do you think about the new boiler idea as he has suggested a condensing boiler whatever that is? possible the reversing valve could be defective,very hard to change on the old saunier,15 years is a good innings ,get a vaillant ecotec Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 (edited) possible, but the part is still available.... saunier duval - reversing valve 15 years is a good innings as you say... but, in these hard times for folk cash wise, 67 quid pus labour is far better then the cost of an eco tec pro 28 (£730 boiler and flue+vat) ok ok, i know sometimes your as well biting the bullet and moving on, but me personally, i would always give the customer the option... i can fix your old boiler and you may get some more time out of it....or you can go for renewal due to its age.... just latley, cash wise, people are going for the repair option everytime.... not having a go here, me personally at 15 years,id get the boiler replaced, but if the parts are tested and CONFIRMED as being at fault, and the part is still available.... well, let them make the choice... again for the record, i love the vaillant eco tec pro 28....if you are gonna change, go for that boiler or at least a worcester 28ij, both good...... Edited February 22, 2011 by myzeneye Quote Link to comment Share on other sites More sharing options...
harrycatcat1 Posted February 22, 2011 Author Report Share Posted February 22, 2011 (edited) Thanks for that myzeneye I will need a while to read it again and try and digest it but I appreciate you taking the time to help. At the moment I will wait and see what this guy my daughter has asked to look comes back with as he is supposed to work on boilers for a housing association or something or other. I could imagine me creating more faults if I started stripping it down edited to say funny you should mention worcester because Bosch come out and fix their boilers for about £250 no matter whats wrong with it, my lad had a plumber out when his bosch went wrong and he charged him £150 odd and did not cure it so had to call bosch out and they sorted it. Edited February 22, 2011 by harrycatcat1 Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 (edited) it not really stripping anything down doing them tests mate...more a case of observing and prodding a few things...hahaha i havent told you how to do anything other then find out what is at fault....hahaha incidentally, im the lead engineer for a housing trust, i look after 9.5 thousand houses see what he says.... as i said, usually alot of folk will just suggest renewal given its age, but as i said, if the parts are available..and its one of the cheaper parts that has failed....why not repair ? Edited February 22, 2011 by myzeneye Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 (edited) Thanks for that myzeneye I will need a while to read it again and try and digest it but I appreciate you taking the time to help. At the moment I will wait and see what this guy my daughter has asked to look comes back with as he is supposed to work on boilers for a housing association or something or other. I could imagine me creating more faults if I started stripping it down edited to say funny you should mention worcester because Bosch come out and fix their boilers for about £250 no matter whats wrong with it, my lad had a plumber out when his bosch went wrong and he charged him £150 odd and did not cure it so had to call bosch out and they sorted it. thats cos the worcester bosch engineer knew what he was doing. hahah or maybe he just "threw parts at it till it worked" as some poeple do... dont think that engineer would last long at w/bosch if that what he did...hahaha i understand how hard it is for people to find a decent engineer and there are alot of plebs out there who think they'l have a go... i understand how people can come away with a bad idea about boiler engineers....but what can you do.. unfortionaitly, membership of gas safe only means that you have passed a set of exams....usually on whats called core gas saftey and then the basic principles behind installation and servicing and regualtions of various appliances.... it does not however prove you have any further knowledge of the inner workings of appliances or more alarmingly anything at all to to with any electical/electronic testing, which is what most fault finding is based around.... remember...... gas safe.... not a guarenteed seal of aproval or technical abiltly..... Edited February 22, 2011 by myzeneye Quote Link to comment Share on other sites More sharing options...
beerdeor Posted February 22, 2011 Report Share Posted February 22, 2011 Replace the giannoni valve with a genuine part don't mess about with changing the diaphragm just change the whole thing will save a load of heart ache in the long run atb Jim Quote Link to comment Share on other sites More sharing options...
myzeneye Posted February 22, 2011 Report Share Posted February 22, 2011 Quote Link to comment Share on other sites More sharing options...
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