W
wisewol
I have a Potterton Performa System 24HE boiler. It is configured in a typical S-plan with 2 external 2-port zone valves (V4043H) along with hot water cylinder stat, a room temperature stat and timing controller. In general it has been a reliable boiler.
A few years ago, it started intermittently stopping with the pump/low pressure warning light (60deg) flashing. When I found this situation (and usually a cold house), I found that if I switched it off at the restart switch and on again, it would burst back into life again, only to fail a day or two later. At that time, I found that turning the main boiler thermostat down a bit made the fault appear less often. I didn't call in a plumber as the chances were that when visiting he would find nothing wrong.
After a year or so with the lower thermostat setting, the fault started appearing again, so down went the thermostat a bit further. Recently on this lower setting, the fault started appearing again. Time to start investigating it more seriously.
I happened on one occasion to be next to the boiler when the fault started. The boiler was at full temperature when it happened. Switching the boiler off and on at this time did not reset and start the boiler, it thought about it for a couple of seconds and then started to flash the low pressure light again. However, once the boiler cooled down, switching off and on again did start the boiler again.
I should add, the water pressure is fine, about 1 bar when cold, rising to 1.5 or maybe 2 when hot. The zone valves work OK, heating the hot water when required and radiators when required, or both. The pressure diaphragm seems OK as does the microswitch attached. I recently changed the pump, but the fault still happens. I have seen some posts on this and other forums of similar symptoms, but no real solution. Some indicated soldering on the pcb may be a problem, so I took out the pcb and examined it closely, but saw no evidence of poor soldering.
As with any problem, you cannot try to solve it unless you can repeat it, so I tried a few experiments. Eventually, I found a sequence of events that I could cause the error and repeat it. This is what I can do to get the fault:
Turn the boiler thermostat up to a relatively high setting. Ensure there is demand for HW, no demand for CH, boiler then fires and starts to heat up. When boiler temp gets to 80C (as indicated by front panel lights), burner still on, remove demand (switching override on controller next to boiler). Burner goes out, pump stays on. After 3 mins, the pump stops and then warning light starts to flash. If I do the same experiment, but remove demand when at 60C, when pump stops, boiler OK and lights just show the temperature.
Anyone any idea what might be wrong with the boiler?
A few years ago, it started intermittently stopping with the pump/low pressure warning light (60deg) flashing. When I found this situation (and usually a cold house), I found that if I switched it off at the restart switch and on again, it would burst back into life again, only to fail a day or two later. At that time, I found that turning the main boiler thermostat down a bit made the fault appear less often. I didn't call in a plumber as the chances were that when visiting he would find nothing wrong.
After a year or so with the lower thermostat setting, the fault started appearing again, so down went the thermostat a bit further. Recently on this lower setting, the fault started appearing again. Time to start investigating it more seriously.
I happened on one occasion to be next to the boiler when the fault started. The boiler was at full temperature when it happened. Switching the boiler off and on at this time did not reset and start the boiler, it thought about it for a couple of seconds and then started to flash the low pressure light again. However, once the boiler cooled down, switching off and on again did start the boiler again.
I should add, the water pressure is fine, about 1 bar when cold, rising to 1.5 or maybe 2 when hot. The zone valves work OK, heating the hot water when required and radiators when required, or both. The pressure diaphragm seems OK as does the microswitch attached. I recently changed the pump, but the fault still happens. I have seen some posts on this and other forums of similar symptoms, but no real solution. Some indicated soldering on the pcb may be a problem, so I took out the pcb and examined it closely, but saw no evidence of poor soldering.
As with any problem, you cannot try to solve it unless you can repeat it, so I tried a few experiments. Eventually, I found a sequence of events that I could cause the error and repeat it. This is what I can do to get the fault:
Turn the boiler thermostat up to a relatively high setting. Ensure there is demand for HW, no demand for CH, boiler then fires and starts to heat up. When boiler temp gets to 80C (as indicated by front panel lights), burner still on, remove demand (switching override on controller next to boiler). Burner goes out, pump stays on. After 3 mins, the pump stops and then warning light starts to flash. If I do the same experiment, but remove demand when at 60C, when pump stops, boiler OK and lights just show the temperature.
Anyone any idea what might be wrong with the boiler?
