Following the extremely expensive installation of a new boiler before Christmas, I am left with a noisy system. I am not sure whether the noise is coming from the new boiler, the pump or from the black solenoid thing attached to the Dayton wireless thermostat. It is a loud vibrating hum that wakes me up when the heating comes on in the morning. I also seem to have a lot of air in the system and my two heated towel rails are making loud gurgling noises continuously and have to be vented every few days. Anyway, I don't want to call the installer I had back in. There are literally hundreds of Gas Safe registered engineers in my area on the Gas Safe website, but how do I identify one that really knows what they are doing?