Worcester repairs archive
[Sep, 2017] Worcester Highflow EA fault, ignition lockout
[Sep, 2017] Worcester CDI heat engine failure
[Aug, 2017] Worcester 40 CDI, Fan fault – won’t fire, no fault codes.
[Jan, 2016] Worcester Junior 28i – Intermittent ignition lockout – blocked drain
[Feb, 2016] Worcester 42 CDI – EA fault code – faulty gas valve
[Jan, 2016] Worcester 30Si – Looks ok on the outside? Take a look at the inside.
[Jan, 2016] Worcester 30Si – Leaking boiler – leaking manifold
[Jan, 2015] Worcester 24i Junior – Intermittent hot water.
[Mar, 2015] Worcester 30 CDI – failed pump
[Jan, 2015] Worcester 24i Junior ignition lockout – faulty pressure switch
[Aug, 2014] Worcester 28CDI hot water not working – faulty diverter valve
[Aug, 2014] Worcester 15Ri seemingly dead – transformer burnt out
[Feb, 2014] Worcester ZWB 7-30 – EA fault code, no heating, no hot water.
Worcester Highflow EA fault, ignition lockout – blocked condensate trap
Of all fault codes Worcester boilers may exhibit, the ignition lockout fault code has to be one of the most common faults. If you happen to have one of the Worcester Highflow/HE/CDI models, the ignition lockout with present itself as the EA fault code. It means the burner isn’t lighting or is failing to stay alight or the flame isn’t being detected!
Unfortunately, there can be many causes of ignition lockout to an appliance. As an end user the only thing you can do is check if any other gas appliances have gas. In the case of this particular appliance the condensate trap was blocked.
Unfortunately the diverter valve was also leaking but miraculously hadn’t cause the appliance to stop working, so I replaced the diverter valve and motor as well. Up and running again promptly.
Rik, Elsecar, S74
Worcester 40 CDI, Fan fault – won’t fire, no fault codes.
This fault is one of the less common faults Worcester boilers exhibit. Under demand this particular appliance’s fan would run at full speed and nothing else would happen. No fault code(s), just nothing else would happen from that point onwards.
This kind of fault would generally point to a potential overheat accompanied by its representative fault code. Once that has been ruled out one would generally suspect the printed circuit board. I happened to have come across this fault on a different boiler(Vaillant) once before, and I suspected the fan itself may be a problem. It was the fan. In General printed circuit board failure is not very common on these appliances. When you carry parts for an appliance for service and repair it makes diagnosis a lot easier, even if you have to guess.
The whole appliance was overdue for some maintenance. The parts that were replaced included the fan, main burner door seal, front burner door seal, spark electrode assembly and bearing plate membrane. You can actually see from the images where the front burner door seal had been leaking, somebody had not tightened the screws on the door at some point. Upon inspection of the fan, I suspect that the leak from the burner had some effect on the fan’s circuit board and might have contributed to its failure.
All the parts mentioned I carry as stock items and I was able to get my customer up and running very quickly.
Be sure to get someone who knows your boiler before you start throwing money at parts and labour based on guesswork. Faults like the one mentioned can catch even experienced technicians out. Guesswork is almost always an expense endeavour.
Mr Kilburn, Birdwell, Barnsley
Worcester Greenstar CDI Heat Engine Failure
Of all the problems one may have with a Worcester Bosch Greenstar condensing boiler, Heat Engine failure is towards the bottom of the list. Manufacturers like to give their boiler’s component’s and features exotic names for some reason, Worcester likes to use Heat Engine as a synonym for Heat Exchanger as you may have guessed.
Unfortunately in this case the Heat Engine of a Greenstar CDI has failed catastrophically resulting in a rapid loss of system pressure. I think this particular boiler required a topping up of the pressure every few hours. The customer said they had looked everywhere but could not find “the leak”.
When Heat Exchangers fail like this they leak internally, a bit like internal bleeding, the problem is not obvious. The leaked fluid collects at the bottom of the Heat Engine, flows into the condensate trap or siphon and ends up in the drain. Thus there is no sign of an obvious leak anywhere.
Worcester Junior 28i – Intermittent ignition lockout – blocked drain
Of all fault codes boilers exhibit, the ignition lockout fault code has to be one of the most common faults. In the case of Worcester Greenstar Juniors/Si’s, the ignition lockout is represented with two lights flashing in a certain sequence. It just means the burner isn’t lighting or is failing to stay alight or the flame isn’t being detected!
The drain that the condensate waste went into was blocked, which caused the condensation to back up into the appliance heat exchanger causing it to stop working.
Worcester 42 CDI – EA fault code – faulty gas valve
Of all fault codes boilers exhibit, the ignition lockout fault code has to be one of the most common faults. In this case the ignition lockout is represented with the EA code, don’t ask me what EA stands for as Worcester themselves don’t even know. It just means the burner isn’t lighting or is failing to stay alight or the flame isn’t being detected!
Most often this fault is indicative of a dirty set of spark electrodes and ionisation probe(flame sensing probe), which either needs cleaning or replacing. Sometimes the fault is related to an issue with a blocked heat exchanger, condensate trap, gas valve or even a bearing plate heat exchanger membrane.
To determine if the heat exchanger is blocked you can connect a digital manometer to a test point(underneath the fan) and test how much vacuum the fan is pulling in service mode. It should be pulling -6mb(give or take) or more.
Assuming the heat exchanger isn’t the cause of the issue next up is the condensate trap. When the condensate trap is blocked you can usually hear water being slapped around at the bottom of the heat exchanger. To rule this out completely you can just remove the trap and see if the boiler fires up.
A faulty gas valve is not uncommon on this model of boiler. Having said that its not a cheap part so you need to be thorough with your other checks first to rule other things out. You can reset the gas valve to its default setting. Which is this – turn the minimum screw(on gas valve) clockwise until it stops and three turns anticlockwise. The maximum setting is done by turning the maximum screw(underneath the fan) anticlockwise until it stops and then one and an eighth turns clockwise. The boiler should fire up at this if the valve is ok.
You can also check the resistance on the gas valve if you suspect this. It should measure 380 ohms on the two top pins(minimum) and 190 ohms on the bottom two(maximum). Worcester advise of a tolerance of around 30 ohms, but in my experience a Worcester gas valve even slightly outside of these parameters is faulty.
Its not very often that a blockage stops a gas valve from working properly but I generally remove the valve and check anyway. You almost always find a bit of build up on the mesh filter inside the valve but usually it doesn’t cause an issues. Removing a blockage is much cheaper than replacing a valve though, or anything else for that matter!
Worcester 30Si – Looks ok on the outside? Whats happening on the inside? Take a look.
I was called to give this boiler an annual service as it was overdue, this appliance was only eight years old. Upon fist glance the boiler appeared relatively healthy. However upon closer inspection after removing the cover it was clear that there was a serious problem with this appliance. It turns out the the flue had been leaking internally for quite some time and had been leaked through the outer part of the flue and had been “repaired” by someone 18 months earlier.
The “repair” was done by wrapping the flue with closure plate tape to stop the leak. This worked for some time but was still leaking internally inside the boiler and started leaking onto the top of the boiler again. The condensation caused by flue gasses from natural gas are corrosive and will corrode metal over time. This leak eventually caused a hole in the top of the boiler casing which has made the boiler beyond economical repair.
This boiler has been replaced. Its a real shame though because these are really good little boilers and this one still had plenty of life left in it, or would have. All it needed was a replacement flue 18 months earlier. Also it meant the customers were without heating and hot water until the appliance could be replaced. Whats more is that it is not uncommon to have a boiler installed inside a bedroom. Imagine this was installed in one of your bedrooms?
For anyone in doubt as to whether or not an annual service is worth the cost, hopefully this persuades them.
Worcester 30Si – Leaking boiler – leaking manifold
This was quite a common fault on the Worcester Greenstar Junior and Si. There is a manifold on the left hand side of the boiler which is made from plastic. These manifolds would get a tiny pinhole in them and cause a tiny jet of water to be sprayed from them, this is water under mains pressure resulting in a small but uncontrolled leak from the left hand side of the boiler.
The tiny jet of water is usually barely visible to the eye. Isolating the mains water supply to the boiler is a short term fix until the part can be replaced. Very common issue on these boilers, but nothing terminal just a relativley straight forward repair. This particular boiler was stripped down and serviced at the same time.
Worcester 24i Junior – Intermittent hot water, blocked plate heat exchanger
This particular boiler didn’t have the system flushed out properly when it was installed which led the plate heat exchanger(hot water) to start to get blocked. Depending on the severity of the blockage and make/model of boiler, this fault may present itself in a number of ways but always effects the hot water in some way. In this case the boiler would deliver nice hot water for a minute or so and then knock off and repeat the cycle. This gave very hot water, then luke warm and hot water again.
Worcester 30 CDI – No heating, no hot water, failed pump
This boiler would just overheat when you put a demand on it. The pump had failed altogether, this boiler has a special pump with variable speed control on it. It is not usual for a pump to just burn out completely, often the impeller gets jammed for whatever reason. This one needed to be replaced entirely though.
When these boilers overheat they often display a U code, like U9 for example, which goes down slowly. This can be mistaken as a fault code, but when the temperature exceeds 100 degrees centigrade the display reads U which means it is over 100 degrees.
Worcester 24i Junior – Boiler failing to ignite ignition lockout
On a lot of older boilers you have a pressure switch which checks to make sure there water in the system before the boiler will fire up. Often these get blocked up which can make then stick on or off. Sometimes they just stop working altogether and need to be replaced.
This boiler would spark for a second then go to ignition lockout, which can mislead you into thinking that its a faulty printed circuit board.
Worcester 28CDI Combi – Hot water not working. Pressure gauge broken.
This one was relatively straight forward, albeit in an awkward little cupboard. The diaphragm in the diverter valve had split which stopped the hot water from working. There is a service kit you can get to replace the diaphragm, but in my experience its more cost effective to replace the whole diverter valve so this is what I did. The expansion vessel was flat so I recharged this to 0.75 bar, cleaned the pressure relief valve and replaced the broken pressure gauge.
I like these older Worcester boilers, they seem to have a well thought out design, are built well and seemingly were built to last. Which is a lot more than I can say for a lot of other boilers. Things like the diverter valve go wrong at some point on these boilers, but this is just general wear and tear. If I had one of these I wouldn’t be in a hurry to replace it.
Worcester 15Ri – Boiler seemingly dead would not work.
This was quite a straightforward fix. The Printed Circuit Board was blowing fuses when you turned the power on. On most Worcester boilers they have a transformer on the PCB which can be removed. Once I had removed the transformer I could tell straight away that something wasn’t right. A quick double check with my multimeter confirmed this.
These are good little boilers though, as far as I know they don’t go wrong very often.
Worcester ZWB 7-30 – EA fault code, no heating, no hot water.
On this particular boiler the spark electrode assembly needs to be replaced every so often. There is a piece on the assembly which detects if there is a flame present and this generally degrades over time needing replacement. Like Worcester CDI and Highflow models, if the printed circuit board can’t detect a flame present the appliance will go to ignition lockout showing the EA fault code. Also if the assembly is not cleaned on a service they tend to get fouled up and stop eventually.