Recently Judit and I were a bit worried about our combi boiler in the kitchen, because the water pressure out of the blue has increased to 2 bars from the normal 1.3-1.4 bar range, and it didn’t really seem to decrease over time.

At this point I should have realized that knowing something about the “normal” operating water pressure levels could prove useful, but oh well. Anyways, after worrying for a bit, and then a bit more, I’ve decided to look up how to release the pressure of the boiler so that the water pressure can go back down to the 1.3-1.4 bar marker.

It turns out that the pressure relief valve on Worcester 24CDi models can be found at the bottom of the unit, to the right with a red cap. Turning it anti-clockwise should result in relieving the water pressure. Excellent..

Once the pressure was relieved, and the pressure level went down to the normal 1.3 bar, everything seemed okay, and we felt relief ourselves as well. Later on during that day we’ve seen that the water pressure has dropped now below 1.3 bar, and it seems to continuously drop over time. After refilling the tank a couple of times, we came to the conclusion that now we have a leak, and it is really time to call a gas engineer.

Lessons learned:

• the water pressure is actually perfectly fine around 2 bars, and usually the boilers are configured to automatically relief the extra pressure at ~3 bars
• when the pressure relief valve is used, quite often the relief valve won’t shut properly afterwards, causing a leak
• boilers tend to have a failsafe for too low pressure as well: in such scenarios they just never actually turn themselves on.