I had a problem with heating system pump, it was screeching when I turned on the heating , I had the pump changed , now I can hear the pump working but the boiler comes on as usual and only works for between 30 seconds to 2 minutes, the pipe off the top of the boiler gets hot
Almost sounds like the water is not circulating and the boiler is reaching temp and shutting down. If you have an amp meter try sticking that on one of the pump wires to make sure the pump is running. If it is, you may have a check valve stuck shut. I would call back the person you had change your pump and tell him you heat is not working. You mentioned the pipe off the top of the boiler gets hot, do the pipes 10-15ft away from the boiler on that same circuit get hot? If not than this again proves there is a restriction in the circuit. Good Luck!
It could be the flame sensor (thermocouple) needs cleaned. When this gets dirty it can't detect the flame so it automatically shuts the gas off after it tries to light. Simple fix really but you need to be able to locate the sensor first. Check your manual and/or Google the make and model of your boiler. Once you find it some steel wool works or emery cloth works great to clean it with. This has nothing to do with the gas supply it just sends a signal to the solenoid that releases the gas to the burner if it detects a flame.
