Glowworm Flexicom CX Heating Not Working Properly

A friend of mine who is also a heating engineer asked me to look at a Glowworm Flexicom CX which a customer of his was having trouble with. He had serviced the boiler 6-7 months ago and the lady had called him back because it was not working correctly and hadn't been since he had serviced it apparently. During the summer one of the radiators had been getting hot when the hot water was run for extended periods and warm even when the hot water was run for shorter periods.

With the winter weather turning colder the lady began to use her heating and not all of the radiators were getting hot. Two of the three upstairs radiators were getting red hot, the other lukewarm. One of the radiators downstairs was getting lukewarm but the others were hardly getting warm. The boiler was getting up to temperature really quickly and then cutting off taking a while to cool down before relighting. When the status display was on it would run through the central heating status mode as normal eventually ending up on S7 the central heating pump over-run status. Then it would go to S97 where the boiler checks the water pressure sensor, and suggests you check the connection to the water pressure sensor and that the pump has not seized. Both of which appeared to be fine. The boiler flow was very hot when the boiler was running and the return was barely warm.

Another engineer had previously removed and cleaned out the water pressure sensor just after the boiler had been serviced and said there was a fair amount of debris fouling it. My friend also said that there was some debris when he drained one of the radiators. From this I assumed that the diverter valve may have been fouled with debris and not moving correctly between the heating and hot water positions. I drained the boiler and removed the diverter valve. To remove the diverter valve all three of the screws had to be removed fully before the diverter valve would come out, the bottom one was particularly tricky to access but managed to get it out with some needle nosed pliers.

After removing the diverter valve the remaining water in the boiler which leaked inside the boiler was really clean and there was no sign of any debris in the diverter valve. However it didn't look as if the motor was attached to the spindle of the diverter valve. I removed the motor from the diverter valve assembly and the spindle was free to move. I reconnected the spindle and fitted the motor back to the diverter valve assembly.
I then re-filled and tested the boiler. I ran the hot water and it was heating and modulating as it should to heat the water to an even temperature. I then switched the heating on and the motor moved the diverter valve in towards the back of the boiler and the connection to the spindle was visible through the hole in the diverter assembley close to the white plastic section. Opening the tap the motor pulled the spindle back outwards, and stayed there for a while after the tap has closed before the motor pushed the spindle back in.

I checked around all the radiators and they were all getting hot as they should be.

Glowworm Ultimate No Heating or Hot Water

After returning from a holiday abroad to the cold of this country one of my customers had to call me out because they had no heating or hot water. The first thing I did was look at their Glowworm Ultimate boiler because they said that they could not see the pilot light. I removed the bottom tray and could see from the gas valve that there was no permanent pilot and that being the fan-flued Glowworm Ultimate had automatic ignition (the pilot lights itself as and when the boiler needs to fire up).

It was at this point that I noticed that the overheat button on the controls fascia was sitting out. I pushed on the button and sure enough it clicked as I reset it. As soon as I reset the overheat button the boiler came to life and fired up. I hung around at the boiler for a moment to ensure that the system was circulating and not likely to overheat immediately. The boiler was running fairly quietly so went to check around the rest of the system.

I told the customer that it may have been caused by a bit of air or if there was a power cut whilst the boiler was running. He replied by saying that he had been having unrelated issues just before he went on holiday. He had asked a friend of the family to replace the immersion heater which turned out to be faulty and kept tripping the electrics until it was replaced with another unit. The plumber had also broken a part on the heating system and ended up draining and refilling the system to replace it and the pump. Like I had already said the boiler overheating was either due to cutting out of the electrics or air in the system. After resetting the boiler the system is working as it should be again.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Ultimate Whining Noise

I was called out at the weekend because a customer was concerned at the noise their boiler was making. Unusually I could even hear it over the phone whilst the customer was talking to me. It was quite a high pitched noise and almost sounded like there was a washing machine on fast spin. As soon as I heard it when I was in front of the boiler I could immediately tell that it was the fan that was making the noise.

Due to the was these boilers work the fans are subjected to quite high temperatures over their lifetime and it is no surprise that they fail. The bearings in the motor often dry out and begin to emit a whining noise. If left too long the friction in the motor can cause the fan to seize and burn out. Fortunately the customer was wise to the fact that something wasn't quite right and called me before they were left with no heating or hot water.

I replaced the fan, each if which is different for each model. The fans come on a plate which has varying sized holes in the bottom depending upon the boiler size. Also the bigger boilers have bigger windings on the fan to increase the rotation speed and exhaust of gases. The boiler is now running much better and the customer was surprised how much quieter the new fan is.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Cxi Dripping and G10 Seal

A friend of mine recently moved into a new house and asked me to look at his boiler as there was a couple of outstanding issues left by the previous owner. Before moving into the house he had been told by an engineer that inspected the heating system that the boiler required a new G10 burner door seal. He was also told by the previous owner that there was a regular drip, hence the bowl underneath.

Looking at the burner door I could see that the boiler had the earlier burner door seal fitted. The main seal looked to be ok, but there was signs of staining at the bottom of the burner door where the smaller seal is. I knew it was likely to be the earlier seal as the burner door was secured using the earlier nuts which are not of the Nyloc type. I removed the burner door and exchanged the earlier 'rubber' seal for the graphite one. The lower seal is still made of 'rubber'. I also filled in the label with the date and stuck this to the boiler so the seal should get replaced in five years time.

The dripping I immediately noticed was coming from the disconnnector. The disconnector valve is the fancy non-return valve they have fitted to the built-in filling loop. It is quite common for them to drip just after re-pressurising the system, and sometimes the dripping stops after a minute or two. Unfortunately  the disconnector had been dripping for an extended period and required replacement with part number 802600. This part comes with a new disconnector valve and an upgraded filling tap. The earlier taps were plastic internally and use to seize and break shut, whereas the new ones are brass internally.

Had the disconnector not been leaking it would have been cheaper, and quite easy on this installation to use a standard filling loop on the existing pipework. After installing the new filling loop I repressurised the heating system which due to the low local water pressure was a struggle to get to 1 bar. The disconnector dripped after filling for a short period which I expect is a consequence of the low water pressure and would consider fitting a standard filling loop on my next visit.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Compact No Central Heating

Was asked by a lady to look at her Glowworm Compact as her central heating was not working. The hot water was working, but she did complain that it was a too hot if anything of late. The lady could not understand why the boiler was constantly running even though the central heating was turned off on the timer.

Looking at the boiler it was running even though the timer was turned off. Looking at the symbols on the boiler I could see that the tap symbol was illuminated even though there were no taps running and the boiler pump was running. I turned the timeclock on but nothing changed with the boiler. I opened the tap and the water was very hot, and cooled a bit before the boiler fired up.

After I turned off the tap, the boiler still continued to run for a while before getting too hot and cutting out. The tap symbol remained illuminated. I ran the tap on and off a couple of times and the tap symbol extinguished, then the heating symbol came on and the heating began to work. I tried the hot water once again, and after I turned the tap off the tap symbol stayed illuminated.

I removed the hot water microswitch on the right hand side from it's position over the pin which operates it. Once removed the hot water symbol extinguished and I could see that the pin was still out quite a way as if a tap was open. I was able to push the pin back in with my hand which I should not be able to do if a tap was actually open.

I replaced the diaphragm (Parts Center 440776) in case it had stretched and the diaphragm cover (Parts Center 440100) in case the pin was corroded and sticking. Another happy customer with working heating and hot water.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Cxi Dripping Water

I was called by a customer to look at a Glowworm Cxi which intermittently would have water dripping from underneath. The customer had a bowl underneath the boiler and pointed to the corner of the case on the front left at the bottom and had seen water dripping from there.

I looked around the bottom of the boiler and could not see any signs of water on any of the joints or at the disconnector. I opened the case of the boiler to see if there was any signs of water inside the case. I could see some brown staining on the 'floor' of the inner case and it ran across from the front left corner to the condense trap. There was a couple of droplets sitting on top of the condense trap.

I checked the route of the condense pipe which ran into the waste pipework below the kitchen sink. Fortunately it was connected using threaded fittings and so I was able to disconnect the condense pipe from the waste pipe easily. Sure enough it was full of gunge due to the way it had been connected in under the sink, waste had been slowly accumulating in the condense pipe before blocking it up. I managed to get a fair amount out into a bowl. Leaving the condense disconnected I poured a little water into the inner flue using a jug which flushed through the condense pipe.

During the summer their probably was not a great deal of condensate produced with just the hot water in use. However, turning the heating on revealed the problem as the amount of condensate would be increased.

This has solved the leak in the short term but have advised the customer to have the drainage altered to prevent the condense from blocking again because it could cause more expensive damage.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm CXi Leaking Hot Water Flow Sensor 2000801910

Was called to look at a Glow-worm CXi today because there was water leaking from the bottom of it. Looking at the boiler it was difficult to see where the leak was coming from. I could see water dripping from the bottom of the boiler near the right hand side of the plate heat exchanger. Looking from side I could see the connections to the plate heat exchanger and there was no sign of water there. It was not coming from the rear of the pump housing either. It looked to be coming from between the filling loop and the pump housing. Then I caught sight of a drip, it was coming from the hot water flow sensor's connection to the pump housing.

I stripped out the flow sensor by removing the filling loop connection and inlet filter, and disconnecting the cold inlet pipe. I suspected that the o-ring may have failed or that the pump housing had split. The o-ring looked good, but there was what looked like limescale coating the flow sensor and so assuming this problem began to clean it off. As I did so I noticed that the plastic had become soft and I was able to damage it quite easily with my nail and so decided to replace it with a new one.

The old one pictured above has been superseded by part number 2000801910 which is now made of black plastic and retails in Plumb Center for £106+VAT under part number 442716. A surprisingly costly part considering it's size and lack of complexity. Replacing the flow sensor solved the leak which was good, after a couple of days I noticed that there was actually a split in the old part as pictured below.

Disclaimer:

The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem.

Work should only be carried out by persons qualified and competent to do so.

Glowworm Economy Plus Not Lighting

Was called by a customer today because they had no heating or hot water. The boiler sounded as if it was working but there was no flame. When I looked at it I could hear the fan running so I knew it was receiving demand. There was no flame visible and there was no sound of ignition.

Usually in most cases I would assume that the fan was running slowly or that the air pressure switch was not working. However, I have seen this problem happen a number of times on these boilers and new it was likely to be a blocked air pressure switch hose. I pulled off both the hoses at their connection to the fan and 'rodded' the connections using an Allen key (with the boiler off obviously). I then reconnected the hoses, replaced the cover, and fired up the boiler succesfully.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Fuelsaver Mk1 25-30B Case Seal

I had a call from a lady asking me to look at her Glowworm Fuelsaver Mk1 25-30 boiler, GC No. 41 315 79.

The pilot light had extinguished and her son had fixed it by replacing the thermocouple but now there seemed to be a smell of gas coming from the boiler. The first thing I noticed when I arrived was that the case was not on properly at the top and assumed that this was where the smell was coming from. Removing the boiler front I could see that the case seal was not in the best condition and couldn't guarantee a good seal even if the case was fitted properly. There was quite a bit of damage at the top in the centre either where engineers had levered the case open at the top or where the retaining clip of the case front had damaged the rubber.

I carried out a tightness test and found a 1 Mbar drop which is enough given the smell of gas to switch off the appliance. There was no drop indicated when the appliance was isolated and so it was definitely a leak at the boiler. Using leak detector fluid and my Anton gas sniffer I could not detect a leak so it may be that the gas valve was actually passing gas.

I made the boiler safe and made enquiries into a replacement case seal and gas valve but both these parts are obsolete and no longer available for this boiler.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glow-worm 30 CXi Flue Sampling Point Cap 0020031334

I went to issue a Landlord's Gas Safety Certificate at a property which had a Glow-worm 30 CXi fitted. I stripped down the boiler for a service and as I did so noticed that the cap which usually covers the flue probe hole was sitting on top of the boiler. At first I assumed that the previous engineer had forgot to replace it. I tried to thread the cap back on but it was not screwing on. Looking at the plastic cap it had started to degrade, the threads were worn away and the condition of the plastic was deteriorating. The thread on the flue which the cap screws onto looked to be in good condition.

The boiler is the older version which had an earlier Vaillant flue terminal. The flue sampling point is on the bend of the elbow unlike the equivalent Vallaint combination boiler which has a separate flue adaptor on top of the boiler with an inner and outer flue sampling point and different caps with different threads.

I asked in Parts Center regarding this part and was given a retail price of £53+VAT and told they only come in packs of five. The part number is 0020031334. The going rate appears to be around £40+VAT online, but our price at Parts Center was £30.10+VAT which is still a lot for 5 plastic caps and washers. For a critical safety item to have failed at this boilers age is not good and these new ones I hope are better made. There is a Technical Bulletin which covers this issue, number 138.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Energysaver 2 Combi 100 Faulty Hot Water

Another engineer asked me to look at a Glowworm Energysaver 2 Combi 100, the boiler was fairly old, but had only been installed three years ago. Asking if I'd seen one before, I told him that I'd replaced one once, and fortunately I had kept the instruction book in my van.

The customer had been using the boiler with the front case removed as this seemed to help the boiler to work. When the boiler was in operation there was quite a strong smell of fumes, and it felt as if there was heat coming back out of the fan inlet. After the boiler had run for a couple of minutes and started to ramp down there was a loud vibrating noise that continued until the flame went out. There were no error codes displayed on the boiler.

I suggested that the noise and smell were due to poor combustion, and that the engineer should get hold of the necessary seals before carrying out a full strip down service. It may be that the combustion just needs adjusting, but due to lack of servicing it could be that the heat exchanger is partially blocked. This would explain why the boiler worked better with the casing off. In the interests of safety the boiler was disconnected from the gas supply so it could not be used before a service was carried out.

We asked in Parts Center about a some seals for the heat exchanger that may need to be replaced on the boiler during servicing and we were told that the lower seal was still available, but the upper seal only comes with the heat exchanger that cost over £500+VAT. As we were not 100% confident at being able to fix the boiler without replacing the heat exchanger and there were other parts also required to fix the boiler, the customer decide to have a replacement boiler fitted.

Glow-worm Ultimate not lighting

Glow-worm Ultimate not lighting every attempt. Sometimes it lights straight away, other times it sparks for a long time before lighting. A common problem on these models, the pilot jets get blocked quite easily reducing the size of the pilot flame. This can prevent enough gas getting through for it to light the pilot flame, or the flame is too small and the boiler fails to rectify the flame.

To rectify this, the pilot injector is removed from the pilot assembly. This injector is unusual in  that there are two holes in the injector for gas to pass through. Both these holes need to be clean and unobstructed. A simple way to clean the through is to put some water into the injector and force it through. Once the holes are clear of any obstructions the boiler can be re-assembled and relit. This time the pilot lights first attempt with a good flame, and crosslights the burner.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Flexicom 15HX F1 Fault Lighting With A Bang

I was called to look at a Glowworm Flexicom 15HX which a customer was concerned about. The boiler was just over two years old and had been serviced six months ago. The boiler had occasionally been lighting with a bang for some time but not every time it lights. This was occuring prior to the service but the engineer was unable to establish a cause.

I checked the gas inlet pressure, and the combustion performance which were both perfect. I removed the electrode and there was slight distortion to the probes and some darkness to the tips. I replaced the electrodes and the boiler is lighting a lot better and the problem should hopefully be solved.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Ultimate Failing To Light

I was called to look at a Glowworm Ultimate which was failing to light today. Upon arrival it was still attempting to light as I could hear it sparking. Sometimes the ignition lead wears through at the point where it passes through the casing, but insulating this with electrical tape usually solves this problem as was already the case with this boiler.

After removing the case the spark could be seen at the ignition electrode and there was a tiny flame but not big enough for rectification to occur. I turned the boiler off and stripped out the pilot injector. Holding it up to the light there should be two holes clearly visible. In this case there was only one hole partially visible. I ran it under the tap and blew through the injector forcing the water through until both holes were clear.

After replacing the injector and case, I lit the boiler which ignited first time, solving the issue.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glowworm Micron 50FF Lights Flashing

Was asked to look at a Glowworm Micron 50FF because the lights were flashing and the heating was not working. Upon arrival I could hear a slight hum from the boiler which felt warm, but not as noisy as usual when running. Both the burner light and the reset light were flashing as this boiler had the latest board fitted which displays fault diagnostics through the green LEDs as opposed to the original PCB with orange LEDs.

I had a look at my chart to diagnose the fault.

The reset LED was flashing fast, and the burner light flashing slow which tells me it is related to the fan or APS (air pressure switch). From the slight hum I could hear I had already assumed that the fan was seized. Removing the case I could smell the motor where it had been trying to rotate the fan, and there was some scorching to the motor windings. The fan motor was also red hot. Fortunately I isolated the power whilst I went to pick up a replacement fan which helped it to cool down.

I replaced the fan, and is running well.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.

Glow-Worm Spacesaver Not Working

A lady asked me to look at her Glow-worm Spacesaver as her heating and hot water were not working. I first notice the pilot light is still lit, but it has been turned off at the fused spur. The lady joins me at the boiler.

Lady: Do you think it has something to do with the electrics?
Me: Why?
Lady: I was using my washing machine, then the power went off and the heating hasn't worked since.

I look at the consumer unit and see that one of the main isolators has tripped. Resetting the isolator, the boiler starts working. There are no obvious leaks at the boiler or airing cupboard which would cause the electric to trip.

Lady: Do you think that's what the problem was?
Me: The heating won't work without power.
Lady: I don't know why that happened.
Me: Neither do I, maybe you should get an electrician to check it out.