Voyager1947
New Member
Your new boiler Honeywell control is a more sophisticated smart control and aquastat combined into one unit, it supplies its own 24v internally from the TT terminals and performs logic contol of the circulator.
The installer must have put a relay to isolate the two transformers so when either Tstat called a "dry contact" was made with the relay, basiclly to short the TT terminals, hence turning on the boiler.
You said you "removed this relay", what did you put in its place?
Are you sure you have the same type of zone vales as shown in that diagram?
Not sure I have the same type of zone valves, but every schematic I saw looked just like this one, so that's how I wired it after I removed the relay, I put nothing in place of the relay. I'm fairly confident the installer didn't put the relay in for any "electric" reason. At first he wired it without the relay, but couldn't make it work. He was trying all kinds of combinations of connecting the zone valve wires, does this go to terminal 1, lets try it on 2, no lets try it here, etc. I didn't have much confidence. Why he put the relay in, I don't know, but there was no discussion about isolating anything, or anything like that. All I know is that once he got it working, it was very loud when it operated, and being right under my bedroom, I had to do something. When I saw nothing about including a relay on anything that I researched, I removed it and wired as in the earlier post. As I say, it's been working fine since October and still works fine, it's just that occasional circulator run problem. Lately, I've been running one zone to see if it's zone valve related, but too early to tell