An out-of-hours call on a Sunday. The boiler was showing fault E133 and there was no heating or hot water. The condensate trap was blocked; we cleared it and had the boiler running again before we left.
A customer in Sutton Coldfield called our emergency line on a Sunday. Their Potterton Assure was showing fault E133, and they had no heating or hot water. With the case off, we found the condensate trap blocked with sludge and debris. The trap drains away the water a condensing boiler makes as it burns gas; when it cannot drain, the boiler will not run. We cleared the blockage, and the customer had heating and hot water again before we left. We recommended a service, and one is booked in for the following week.
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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
Smell gas now? Do not use this form or wait for a reply. Call the National Gas Emergency Service free on 0800 111 999 (24 hours). If you are using a mobile, make the call from outside. Open doors and windows, do not switch electrics on or off, do not smoke or use naked flames, and turn the gas off at the meter if it is safe to do so, unless the meter is in a cellar or basement. Once the supply has been made safe, we can trace and repair the fault.
The call came in on a Sunday, out of hours, from a customer in Sutton Coldfield. Their boiler, a Potterton Assure, had stopped, and the display was showing fault E133. They had no heating and no hot water. The first photo is a still from our video on arrival: 133 on the screen, with the flame and reset symbols lit.
On Potterton boilers E133 means the boiler could not light, or could not keep its flame. With the case off, we found the cause: the condensate trap was blocked. You can see it out of the boiler in the third photo, stained brown, with the sludge and debris that was blocking it washed out into the sink.
A condensing boiler makes water as it burns gas, and that water drains away through the condensate trap. When the trap blocks, the water has nowhere to go, it backs up inside the boiler, and the boiler shuts itself down.
We cleared the blockage and got the boiler running again, and the customer had heating and hot water back before we left. Our Potterton boiler repair page lists the other Potterton fault codes and what each one means.
Cleaning and inspecting the condensate trap is part of a basic boiler service, so a blocked trap is often a sign that a boiler is due one. We recommended a service, and the customer booked one in for the following week.
Out of hours, including Sundays, we quote the price on the phone before we set off. In office hours (Mon–Fri 8am–5.30pm) a boiler repair is £99, covering attendance, diagnosis and the first hour, with parts quoted before we fit them. A basic boiler service is £95, intermediate £125 and a full strip-down £185. Details are on our 24/7 emergency page and our price list.
On Potterton boilers, E133 means an interruption of the gas supply, an ignition failure or a flame not detected: the boiler tried to light and could not, or could not keep the flame. A blocked condensate trap is one cause, as here. Others include the gas supply being off, a prepayment meter out of credit, a frozen condensate pipe in cold weather, or an ignition fault.
Check that your other gas appliances work and that any prepayment meter has credit, then press reset once. If the code comes back, stop resetting and call an engineer with the code and the model. If you can smell gas, call the National Gas Emergency Service on 0800 111 999 first.
A condensing boiler makes water as it burns gas. That water drains away through the condensate trap and pipe. If the trap blocks with sludge, the water cannot drain, it backs up inside the boiler, and the boiler shuts down or will not light.
An annual service. Cleaning and inspecting the condensate trap is part of our basic boiler service, which is why we recommended one here.
Yes. Our emergency line is answered 24 hours a day, seven days a week. Out of office hours, including weekends, we quote the price on the phone before we set off.
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 in the area is on our Sutton Coldfield 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.
A late-night call about a leak. We traced it to the flow adapter on the boiler's right-hand manifold and, with the part on the van, fixed it that night instead of just turning the water off.
Read the case studyA corroded radiator valve had started leaking onto the floor. Dust sheets down first, radiator drained, new valve fitted and checked on the same visit.
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.
