A routine annual service. The boiler itself checked out well: condensate trap and magnetic filter cleaned, combustion readings clean. But checking the flue is part of every service, and up in the loft it was held by nothing more than a strip of metal banding, with the joint clamps left unscrewed.
We carried out a basic annual service on a Vaillant ecoTEC pro 28 combi in an airing cupboard in Kitts Green, East Birmingham. We cleaned the condensate trap and the magnetic system filter, then ran the Regulation 26(9) safety checks. Combustion was clean, with a CO/CO2 ratio of 0.0010 on the analyser. Those checks include the flue, so we followed it up into the loft. There it had no proper support brackets, only a strip of metal banding wrapped round it, and the flue joints were not mechanically secured. We classified the installation At Risk, attached a warning label, left the customer a written warning notice and quoted to bring the flue up to current standards. The customer accepted, and the return visit is booked in.
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Basic service £95, intermediate £125, full strip-down £185.
No travel charge within 10 miles of B20 2JS. Further out, £2 per mile may apply — always agreed before anything is booked. Full price list
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A booked annual service on a Vaillant ecoTEC pro 28 combi, fitted in the airing cupboard of a house in Kitts Green, out on the east side of Birmingham. This was a basic service: the checks every boiler should have once a year.
With the case off, we took out the condensate trap and rinsed it clean. Condensing boilers produce water as they run, and it drains through the trap; if the trap blocks, the boiler can lock out. We also opened and cleaned the magnetic filter on the heating system. The black sludge on the magnet in the third photo is magnetite, which comes from corrosion inside the radiators and pipework. That is exactly what the filter is there to catch before it reaches the boiler.
Then the safety checks. After working on a gas appliance, Regulation 26(9) of the Gas Safety (Installation and Use) Regulations requires the engineer to check the effectiveness of the flue, the supply of combustion air, the operating pressure or heat input, and that the appliance is working safely. The analyser readings were clean, with a CO/CO2 ratio of 0.0010. As far as the boiler itself went, it was in good order.
Checking the flue means the whole flue, not just the part you can see at the boiler. On this house it runs up from the airing cupboard through the loft, so we went up and followed it. Two things were wrong:
Why it matters: the flue carries the products of combustion, including carbon monoxide, out of the house. A flue that is not properly supported can sag or shift over time, and a joint that is not secured can work loose and come apart. In a loft, nobody would see it happen. The manufacturer's instructions and current standards require the flue to be supported with proper brackets and its joints to be mechanically secured. None of this would show up on the analyser at the boiler. You only find it by going up and looking.
We classified the installation At Risk under the Gas Industry Unsafe Situations Procedure: not an immediate danger, but with the potential to become one. We attached a warning label to the boiler, explained the issues to the customer and left a written warning notice, part of which is in the last photo.
We also quoted to bring the flue up to current standards: proper support brackets fitted, and the flue collars screwed so that every joint is mechanically secured. The customer accepted the quote, and the return visit is booked in to get it done.
It should be. A service is not only the boiler: if your flue runs through a loft, a cupboard or a boxed-in void, the engineer needs to see it. If you are not sure when yours was last looked at, our boiler servicing page sets out what each level of service includes.
A basic annual service is £95, an intermediate service £125 and a full strip-down £185. If we find something that needs putting right, like this flue, we quote for it first and nothing is done without your go-ahead. Details are on our price list.
It means the installation is not an immediate danger to life or property, but it has the potential to become one. The engineer explains the risk, recommends turning the appliance off until the fault is put right and, with your permission, does so. Either way you are left a written warning notice that lists the fault and what is needed to fix it.
After working on a gas appliance, Regulation 26(9) of the Gas Safety (Installation and Use) Regulations requires the engineer to check the effectiveness of the flue, the supply of combustion air, the operating pressure or heat input, and that the appliance is working safely. The flue carries the products of combustion, including carbon monoxide, out of the house, so it is checked along its length, not just where it leaves the boiler.
Yes. The flue should be supported with the brackets set out in the manufacturer's instructions, and the joints mechanically secured so they cannot work apart. Metal banding wrapped round the pipe is not a substitute for a proper bracket. If your flue runs through a loft, ask your engineer to check it at the service.
A magnetic filter catches magnetite, the black iron oxide sludge that comes from corrosion inside radiators and pipework, before it reaches the boiler. It only works while there is room on the magnet: once the core is coated, sludge carries on round the system. Emptying it at the annual service keeps it doing its job.
Job attended and photographed by our engineers, October 2026. Written up by Saeed Iqbal, the engineer who leads Synergy Gas & Plumbing (Gas Safe registered 594385). More of our work across the city is on our Birmingham page, and every job we write up is on the case studies index.
From £95
Basic service £95, intermediate £125, full strip-down £185.
No travel charge within 10 miles of B20 2JS. Further out, £2 per mile may apply — always agreed before anything is booked.
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Read the case studyWe check the whole installation, flue included, and tell you straight what we find. Anything that needs putting right is quoted before it goes ahead.
