Thank you for that very detailed post Mandate. The initial impression was 'What on earth does that lot mean'. However, in conjunction with the information in the Honeywell pdf document it all made sense.
The situation seems to be resolved. Your comment about the programmer prompted me to open...
Finally managed to check voltages and found the following:
heating only - white 240 grey 64
hot water only - white 9.4 grey 94
heating + hot water white 240 grey 67
Does this suggest any particular area at fault? PCB components? The values certainly do not conform to those in the link in...
Thanks Mandate. Fingers crossed it is the motor however I'll check out the voltage values tomorrow hopefully.
Found the following link in another post giving the mechanical and electrical operation. It won't hurt to reproduce it here.
http://content.honeywell.com/uk/homes/FAQ/v4073aop.pdf
I wonder if one of you could explain the purpose of the lever on the front of the 4073 marked Auto/Man. Although it might appear obvious.
I moved into my current house 10 years ago. Soon afterwards the central heating radiators failed to heat up when the system was running. After a bit of...