The customer's Vaillant ecoTEC 937 kept having to be reset, and its last ten faults were all F.62 and F.75. We replaced the PCB from our van stock and a blocked pressure sensor, recharged the expansion vessel, and gave the boiler a full strip-down service with a new burner seal, all on one visit.
On Wednesday 4 November we attended a Vaillant ecoTEC 937 in Great Barr for a service and repair. The customer told us the boiler was having to be reset regularly. In the fault history, the last ten faults were all F.62 and F.75, and when we first tested the boiler it went to F.62. We diagnosed a faulty PCB, which we carry on the van, and replaced it. For the F.75, we found the pump working perfectly; we took out the pressure sensor, found it blocked and replaced it, and recharged the expansion vessel. We then carried out a full strip-down service with a new burner seal, walked the system and bled the radiators. The customer was extremely impressed, and has asked us to book in services and landlord checks on their other properties.
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£99 in office hours (Mon–Fri, 8am–5.30pm) covers attendance, diagnosis and the first hour. Parts and any further work are quoted and agreed before we carry on. Out of hours, the price is quoted by phone before we set off.
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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The customer told us their Vaillant ecoTEC 937 was having to be reset regularly. We attended on Wednesday 4 November for a service and repair.
We checked the boiler's fault history: the last ten faults were all F.62 and F.75. When we first tested the boiler, it went to F.62, which you can see in the second photo.
We diagnosed a faulty PCB, the boiler's main control board. We carry that part on the van, so we replaced it on the same visit.
F.75 means the boiler has failed to detect a sudden pressure increase when its internal heating pump starts up. We found the pump working perfectly. We took out the pressure sensor and found it blocked, so we replaced it, and we recharged the expansion vessel.
We then carried out a full strip-down service, replacing the burner seal, and finished by walking the system and bleeding the radiators. Our Vaillant boiler repair page covers other Vaillant faults.
The customer was extremely impressed, and has asked us to book in services and landlord gas safety checks on their other properties.
In office hours (Mon–Fri 8am–5.30pm) a boiler repair is £99, covering attendance, diagnosis and the first hour, with parts quoted and agreed before we fit them. A full strip-down service is £185. Details are on our price list.
F.75 means the boiler has failed to detect a sudden pressure increase when its internal heating pump starts up. A failed pump can cause it, but on this boiler the pump was working perfectly; the pressure sensor was blocked, so we replaced it.
A boiler that is being reset keeps a record of the faults it has had. Here the last ten were all F.62 and F.75, which told us both faults were coming back, not a one-off.
No. A reset clears the display, not the fault. If you are resetting it regularly, call an engineer with the fault code and the boiler model.
In office hours (Mon–Fri 8am–5.30pm) a boiler repair is £99, covering attendance, diagnosis and the first hour, with parts quoted and agreed before we fit them. A full strip-down service is £185, which includes gaskets and an inhibitor top-up.
Job attended and photographed by our engineers, November 2026. Written up by Saeed Iqbal, the engineer who leads Synergy Gas & Plumbing (Gas Safe registered 594385). More of our work in the area is on our Great Barr page, and every job we write up is on the case studies index.
£99 diagnosis + first hour
£99 in office hours (Mon–Fri, 8am–5.30pm) covers attendance, diagnosis and the first hour. Parts and any further work are quoted and agreed before we carry on. Out of hours, the price is quoted by phone before we set off.
No travel charge within 10 miles of B20 2JS. Further out, £2 per mile may apply — always agreed before anything is booked.
Booked in for a service, the boiler was showing F.75. The original pump had failed after 18 years and its air vent was leaking. New high-efficiency pump fitted.
Read the case studyThe pressure kept rising even with the boiler off. We found a pinholed plate heat exchanger and replaced it, with the pressure relief valve, from the van. No new boiler needed.
Read the case studyWhat a full strip-down actually involves, photographed as we went: fan and burner out, burner door and heat exchanger cleaned, gaskets replaced. Then a walk round the house to bleed every radiator.
Read the case study£99 in office hours covers attendance, diagnosis and the first hour. Parts quoted before we fetch them.
