Blog – The Tiradesman

24 April 2016:

I’ve given my blog a name: it  acts an old curmudgeon’s soapbox, where I  can not only share experiences,  but vent frustrations so I don’t become a threat to anyone. (And also, I hope, give some compliments and praise.)

Boilers – some are too powerful: unfortunately some installers fit “regular” (or “heat-only”) boilers that are way too powerful for the property – perhaps they generally fit combis and fit a regular boiler with the same power. The combi heats water instantly and needs to be powerful.  A regular boiler with the same power might heat half the street.

Boilers in lofts:  a loft can be a good place for a boiler, and although it takes longer to service a boiler in a loft, it beats poor access and ventilation in an undersized kitchen cupboard. BUT, being at the highest point in the system, the boiler will be the first ting to suffer if system water is lost. In addition, the boiler’s indicators and pressure gauge are out of view and if the boiler needs to be reset, you’ll need to get up there to do it. Consider having a pressure gauge and filling loop fitted at lower level. Manufacturers – how about a remote display and reset facility?

More rain: a Potterton Suprima stopped working after a very  rainy day. Rain had entered the air intake (under a failed gutter).  All that needed to be done was empty the water from the tube to the fan air pressure switch and function was restored. In this boiler, parts that might have been damaged by water, are off to the side out of harm’s way.

Peculiar fan: my diagnostic skills weren’t up to a Potterton Suprima HE boiler – the fan ran for some seconds before stopping. It was obviously the circuit board – except it wasn’t – the fan stopped of its own accord – verified by running the fan outside the boiler. A new fan got the boiler going. Don’t understand the fan’s behaviour –  why stop after a lot of revolutions?

Boiler first service in 21 years: serviced an Ideal balanced-flue boiler that was far from new when the owners moved in 21 years ago, and not serviced since. Badly in need of a good clean, and the case seal needed replacement, but when done, the boiler (never had a fault in 21 years) was burning gas very cleanly and quietly (no fan) if inefficiently.

An odd case of a blocked plate heat exchanger: a Keston boiler as it happens, which had shown the signs of poor circulation – variable water temperature (no good for a shower!) and boiler overheating. When removed, I expected to find the exchanger’s heating water path blocked with corrosion debris so was surprised to find lime-scale as the culprit – no question about it – the scale dissolved in acid, and there was no black corrosion debris in evidence.

Flues in voids: still finding the occasional flue in a void with no inspection hatches, in rented properties with clean gas safety certificates – who’s issuing them? From end 2012, such a boiler is “At Risk”.

Rainwater in a boiler – a new case – late July 2014, close to  year after my first case: this time an Alpha boiler, dripping water, with a significant amount found in the air intake pipe under the fan, and water in the gas valve. Unfortunately, attempts to revive the gas valve failed, resulting in an expensive repair. My best theory is that water entered the flue, possibly from an overflowing gutter, in a brief deluge, while at the same time, the water wasn’t able to clear via the condensate pipe (which wasn’t blocked when I checked it) – bad luck. The flue now has a rain shield so there should be no recurrence.

Rainwater in a boiler: during the last week in July 2013, after a rainstorm, attended a Worcester Greenstar 28i junior boiler dripping water. On removing the case, there was a considerable amount of water on the floor of the burner compartment. The tenant thought it was due to the rain, I didn’t, Worcester tech support (excellent people) did, and directed me to the gas valve. On removal, this was found to contain loads of water – I didn’t think it would work again – wrong again – dried it out thoroughly with a hair dryer and the boiler fired again, burning as it should, according to the flue gas analyser. The story may not be over – Worcester reckon this shouldn’t have happened with the newer black flue fitted.

Gas pipes to hobs: Gas engineers occasionally find gas hobs supplied with gas via flexible cooker hoses . Gas hobs should be supplied via rigid pipework that contains an isolation valve, or if there’s a flexible pipe, it can only be permitted if it hangs in a U shape and is not under stress.

Balanced flue boiler: I recently had the pleasure of servicing an old balanced-flued boiler (no fan). It’s sad they’re so inefficient – this Glowworm was small, simple and virtually silent.

Soaking wet loft caused by boiler plume: my friend who installed his new condensing boiler in the “summer” of 2012  some time later had a soaking wet loft due to the plume rising several metres vertically in cold, still air, through the gaps (meant to be there) in his soffit boards, and condensing the remaining water vapour as liquid in the loft. Anyone else had this?. He solved it by  extending the flue exhaust so it discharged well away from the house.

Damaged screw heads prevent proper boiler service: my efforts to do a proper service on a nine or so years old Ideal boiler were frustrated by damaged screw heads, left in that condition by a previous engineer. I didn’t try an impact screwdriver or drill out the screws for fear of causing real damage. The boiler was burning very badly, bad enough to be in the At Risk category. Fortunately, I was able to get at and clean the burner which greatly improved its performance, but a few carelessly damaged screws will probably result in the replacement of  the boiler before its time.

Tech support: I recently repaired a limited edition Jaguar 23 boiler, which I gather was originally produced by Hepworth for Plumbcenter. Most Installation & Service manuals give detailed information on how to replace parts, but this one was particularly lacking on that score. No matter – the boiler is supported by Glowworm and a few calls to their Tech Support people sorted me out and had part numbers instantly to hand. On the whole, I’m very impressed with boiler manufacturers’ tech support staff (there is at least one notable exception among manufacturers, name withheld but I’d tell you in private [11 Nov 12]) – thank you ladies (yes indeed) and gentlemen.

Corrosion products found in a boiler only 2 years old: probably responsible for failure of a pressure sensor, despite the presence of a magnetic filter in the boiler return. Cleaned the filter of fine black magnetite “silt” or “goo”. Tallies exactly with observations of a friend – the magnet collects fine particles – coarse ones can get through.- anyone else find this? Was the filter fitted instead of rather than as well as properly cleansing the heating water? Probably.

Worcester Greenstar 24i System – boiler service from hell. All looked well – the fan (negative) pressure comfortably exceeded the minimum and so indicated the boiler didn’t need a clean, despite not being serviced in the five years since installation. However, flue gas CO2 was considerably lower than the manufacturer’s figure (which has a tight tolerance). Adjusting gas valve to raise it had CO shooting up well over limit. Advised to look at fan baffle, which was fine, so having taken the lid of the burner/heat exchanger, proceeded to clean it – meant removing the burner and two baffles. Bottom baffle wouldn’t budge – used force as advised – came out minus spring. Spent several hours trying to remove coil spring stuck at bottom of heat exchanger until Worcester tech support’s magic suggestion of sodium bicarbonate solution squirted over the spring softened the deposit holding it rigid, and it came out. New baffle set now needed. Fitted these on the return visit after cleaning the heat exchanger, and re-assembled the boiler, which now produced required CO2 with low CO, and burned like new – much joy after the struggle, and for an excellent customer.  Must pay tribute to Worcester’s telephone support team – always polite and helpful. Lesson 1 – use sodium bicarb on stuck baffles before pulling too hard. Not convinced design of that heat exchanger arrangement all it could be. Lesson 2 – an inadequate negative fan pressure indicates one of these boilers needs to be opened, but the converse isn’t necessarily so.

Idea for electronic manuals – dear boiler manufacturers: please supply each boiler with a captive memory stick containing the documentation so it’s always available on-site. If the master of the manual is in electronic form, it can be updated relatively easily and at no great cost, so no more excuses like printing costs and “it’s translated from the German” for not making improvements. Oh yes, and please do what Ideal and some others do: use a digital camera and put pictures in the manual – no more line drawings with lines ending on unidentifiable parts.

Worcester Greenstar 24Ri – easy selection of maximum & minimum power what a delight to have a switch to put the boiler into normal or maximum or minimum modes, and not some strange combination of button presses! How simple to operate. Problem is, a switch costs money  so soon they’ll all be “place your right index finger in your left ear, with your left thumb press and hold the rest button and hold for five seconds while pressing and holding the on-off switch with your right elbow and reciting the Rhyme of the Ancient Mariner. To access the second level service codes….”  

Gas inlets on boilers (undersized): powerful combi boilers burn gas at a high rate and installers struggle to achieve adequate pressure at the appliance, aiming for less than 1 mbar drop in the pipework, and often resorting to 28mm copper pipe. It seems very odd that some manufacturers of hefty boilers (30kW and above), have a gas inlet of 15mm. According to my spreadsheet, you only need 0.5 metre of 15mm pipe with one elbow, to lose 0.5 mbar to a 35kW boiler. So, for the rest of the pipe run, you’ve only 0.5mbar to play with. The same in 22mm would lose less than 0.1 mbar.

Worcester combi boiler 532i (CDi badged by British Gas): bad leak on domestic hot water (DHW) side just before the plate-to-plate heat exchanger. The “flow sensor adaptor”, which restricts the flow, had significantly disintegrated, allowing water back out past the flow sensor (turbine) and eventually through the ceiling below – a lot of hassle from a part costing only £4. After four years of bother, including frozen condensate pipe (not an issue with this particular boiler as such), the poor lady yearns for her (non-condensing) old boiler – 17 years of trouble-free operation. Anyone else keep hearing stories like this? And does anyone else find the Worcester filling loop key can be used to create a water fountain?  

Ariston Micro Genus HE 24: air flow problem (error 34). Changed the air pressure switch to find only minor improvement. Similar result after cleaning the fan. Took tech support’s advice and removed the flue flow restrictor from the flue adaptor on top of the boiler. Had to remove the flue elbow, with the help of the owner chiselling away mortar from around the flue. Reaching in with a finger and pulling out the restrictor from above (looks like a flat metal washer ~40mm diameter) was the work of a moment. Sorted. Not common to have to alter the “build standard” of a product like this – presumably some of these boilers on longer flues are now struggling. A new fan might have helped further, but the owner was spared the expense.

Vaillant EcoTEC plus 428 condensate trap difficult to remove: (heat-only boiler for open-vented service): wanted to clean condensate vessel during a service. No easy removal via handy bayonet fitting, just a rectangular box that tech support said needed to be removed. Tried detaching the two flexible pipes but they didn’t flex enough or detach. Result, couldn’t remove the condensate, and created a leak resulting in a call back. Infamy, infamy, they’ve got it in for me!