No gurgling, and this bedroom actually is the only finished space in my basement. When I click the zone valve lever to manual, the furnace ignites, and the circulator starts pushing hot water to the bedroom. The copper ONLY goes to the bedroom, then returns to the furnace in almost the same route.I have a forced hot water boiler in my house , as well as in a bunch of my rental properties . Im also a builder also and years ago putting in hot water heating systems was the norm. Not anymore though. For the last 20 years its been forced hot air with AC . Im not a plumber but have had to deal with no heat issues enough and fix them myself to save on repair bills.
2 Questions --- Do you hear gurgling in your baseboard heat when the heat is on or when you have the zone turned on manually ? Is your bedroom the 1st room in your basement that the heat zone goes to from the boiler or is it the last room before the heat line returns to the boiler ? I would think there is more than one room finished in your lower level. If your bedroom is the last room before the heat line returns to the boiler and the 1st room is getting heat , but it gets cold by the time it gets to your bedroom , I think you have an air pocket in your heat line. Your zone needs to be purged to get the air pocket out of the line. If you dont know how to do that , let me know. Its fairly simple , but can be tricky. I would want to see a picture of your zone valve assembly. There should be a ball valve with a lever on every return line back to the boiler as well as a spigot. You shut off all the zones at the ball valves except for the one you want to purge. You need a 5 gal bucket and a small hose just long enough to reach the bottom of the bucket. Turn on the spigot about half way to fill the bucket a couple inches then turn it up full. If you are getting spurts of water and sputtering , you know you are on the right track. The tricky part is to watch the pressure gauge on the boiler. You need to manually hold the feed lever to keep putting water in the boiler as you are taking it out of the zone spigot. Keep doing this until you get a full constant flow out of the hose. It might take 10-15 gal of water depending on how long of a run the zone is.
If the entire heat zone is cold with no heat , I think its the motor on your Honeywell zone valve. Very easy fix to replace the motor. All of mine have been Taco zone valves. I just had to make sure I hooked the thermostat lines back in the same places. The wires on a Honeywell zone valve are different but the same principles apply. Hook the wires to the same locations on the new one as to where they are on the old one. Take a picture of them before you start unhooking stuff. Here is a youtube vid on how to replace the motor
Of the 25 or more times I have had to deal with this over the years , twice it was the zone valve motor , once it was the valve itself and had to solder on a new one , once it was the pressure valve on the feed line that added water to the boiler when needed. I know its not this one because your upstairs zones are working fine.
All the rest of the times it was air pockets in the heat line. Its very common to get air pockets when the heat has been off and your lines haven't been used all summer.
Oh man you went about it all wrong ! When you get it fixed turn the heat up full blast ! You want the wifey to shed clothes off ! Not put on winter parkas and hide in igloo sleeping bags ! LOL
Sounds more and more like the zone valve "pop top" as you are suspecting. I am betting the end switch on it has gone bad.No gurgling, and this bedroom actually is the only finished space in my basement. When I click the zone valve lever to manual, the furnace ignites, and the circulator starts pushing hot water to the bedroom. The copper ONLY goes to the bedroom, then returns to the furnace in almost the same route.
I'm fairly convinced it must be the solenoid/zone valve motor, since moving the lever manually makes it work 100% fine, until the thermostat reaches temperature. I had this theory in my head originally, but with low confidence. I'm not a plumber, didn't stay in a Holiday Inn last night, and tend to overthink things. Everyone on here has helped push my confidence up tremendously, and as soon as I know everyone has had a shower (in case I fumble somehow and have to shut the furnace down for a longer period of time) I'm going to swap the valves and see if that gets my wife to shed the bedtime snowsuit.