Sting wrote:If this is still the old mechanical relay system, you can excite the relay manually and proof its operation to close the B1 B2 terminal. Measure voltage at B1 - Is it there? Is C1 C2 closed? if yes then B1 and B2 will be open. This is a poor control device at best for a solid fuel appliance but its cheep.
Whats wrong with jumping the TT points???? The likelihood of the relay failing closed is about as remote as hitting the lottery, and it provides far better boiler control - depending on the rest of the system control.
There is no voltage at B1 or B2 (with the temp below the low temp settings), unless the timer is activated.
There -- you found the problem - now what is the cause? Did you read the link about how to set the Triple A and do you have it set so the b1 and b2 should be closed? forget the TT jumper leave it - forget the MT C terminals - you don't need them - your only using 1/3 of this control so that's all you need to worry about.
I would in this application, park the Triple a and use a SPST well type aquastat for burner control and then strap on a second for a hi limit safety - but thats me.
Still, I am annoyed that when the timer is active you see power at these points -- it must be a back feed --- proof that! You should be able to manually excite the B1B2 relay and close the points with an insulated screwdriver. Nope i didn't write that. i wouldn't do it - you should NOT try this.