Hi, my name is ***** ***** I have been in the plumbing and plumbing repair field for 20 years. I will be glad to help you today. Will you tell me what the system pressure is at the boiler?
Do you know if your circulation pump is running? If so does it seem exceptionally hot?
Are you using a wireless thermostat?
How are you controlling your heat?
Are you familiar with where the diverter valve is? Are you planning on repairing yourself or are you just getting an idea before calling someone out?
It may be that the diverter is sticking. You may be able to get it to not stick. If you remove the motorized valve then try to move the diverter and if the diverter seems to be moving freely than the motorized valve would be the fault. If it is stuck and you free it up then replace the motorized valve and it should work then.
Thank you for your help.
Crazy but it turned out to be a connection block which was used to bypass the old thermostat.
Great quick service have rated you.