A faulty thermal store cylinder had perished beyond repair. Converting to unvented was the best option.


It is difficult to see when a faulty thermal store hot water cylinder is beyond repair. In fact, it can hide the signs of irreparable wear and tear unless you know what to look for. We identified clues that left us no choice but to replace this cylinder. So why did we convert to an unvented hot water cylinder? Simply reason was cost. An unvented cylinder costs less than a thermal store. But if that is the case, why didn’t they fit an unvented cylinder in the first place? Another simple reason: you need to be G3 qualified to install unvented hot water. There are no additional qualifications needed for a thermal store. Parkstone Yorkshire is proud to be G3 qualified.

Cylinders made to last.

Cylinders manufacturers use high-quality materials for their products. It is essential that hot water cylinders can withstand the wear and tear of everyday use. First, the cylinder has to store hot water safely, that much is obvious. Second, the cylinder must withstand the effects of expansion and contraction because water is heating and cooling. Third, the hardness and condition of the water supply can lead to restrictions and blockages of water elements. Finally, it must heat the water efficiently and effectively, so heat transfer is important. In conclusion, most manufacturers offer long warranties because their cylinders meet these demands. So what did we find wrong?

Issues with the coil.

If you were to look inside a thermal store cylinder, you would find a large coil. The coil transfers heat from the body of system water, stored in the cylinder, to the mains cold water, running through the coil. The coil had perished in this faulty thermal store cylinder. This causes the system water in the cylinder to mix with the mains water in the coil. This increases the pressure inside the cylinder. Eventually, a safety device opens. When the pressure exceeds the safety limit the water discharges outside. We discovered running water from the relief pipe, a clear sign that this thermal store cylinder was beyond repair. In addition, a faulty blending valve (which ensures the hot water flows at a constant temperature) meant an unvented cylinder conversion is a cost-effective option.

If you would like any help with your hot water supply, and live in the Leeds area, please get in touch.



Our mission is to offer a high quality service

At Parkstone our mission is to offer high quality plumbing, heating and bathroom solutions. Our team is made up of highly skilled tradesmen and gas safe registered engineers.