Not getting any heat from a zone

I have a two story house with two heating zones, one for the upstairs, and one for downstairs. It utilizes baseboard heat powered by a gas boiler. The baseboards do not have bleed valves on them.

Earlier today, I noticed it was very cold downstairs, and the baseboards were cold, even though the target temp on the thermostat was well above the current room temp. Upstairs everything was fine.

The zone control valves are Honeywell V8043E1020. When I push the lever for the downstairs zone valve to lock it in the manually open position, there is no resistance on the lever and it just swings loosely back and forth and cannot lock into the notch for a manual opening.

System pressure is 20psi and its heated to an appropriate temperature.

I don't know much about heating systems and not really sure what's going on, but figured I'd check here first before calling out a professional.

 

Hi, I'm no expert, but if your zone valve acts like you describe, it's open. Is the circulator running? The "end switch" in the zone valve sends a signal to turn on the circulator when the ZV opens. I've had the end switch fail. If the other zone heats, the circulator must be OK. Does this zone heat when the other zone is on? If so, it sounds like the ZV end switch is the problem. I believe there is a replacement part available that contains the zone valve motor and end switch. You can install this leaving the actual "valve" in place (no draining the system). Hope this helps- one of the experts should be along soon-
Good luck, Steve

 

I'm not sure if the circulator is running - how would I tell? The other zone heats just fine.

The zone does not provide heat, even when the other zone is providing heat.

 

If your other zone heats then the pump is fine because it is common to both zones. If your manual switch has no resistance when moving it means the ZV is at least open and when you call for heat on the working zone both floors should heat heat.

Even if the ZV end switch is defective you can heat the whole house by moving the lever to manual so the valve stays open which it is.

That being said with both zone valves open and only 1 zone heating I would check for frozen pipes in your downstairs zone. Start at the boiler and follow the pipe to the unworking zone and see if it gets cold all of a sudden. Pipe may go by a place with direct draft on it, doesn't have to be below freezing in room, just in contact wit cold draft.

The other reason could be air bound but if it's been working right along highly doubtful unless something changed.

Keep zone valve open so water will flow when heat is called. Turn that stat all the way up to make sure water will flow or attempt to.

Hope this helps a little.

 

Thanks. I just got done replacing the zone valve motor, and that didn't fix anything.
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Here is a picture. The top zone valve is for the second floor, which is working properly and hot to the touch all the way. The zone valve on the right is for the first floor, which is where the issue is. The pipe is hot for a few inches, until that elbow joint where it turns downward, then it quickly becomes cool.

Still not sure what's going on.

 

Did you try to bleed that zone. If you cannot circulate water through the zone my guess is you are frozen somewhere. Follow your entire loop to see if the pipe is in any drafty area.

Pics of the piping and purge station would be helpful.

 

Welp, things went from bad to worse in the ol' Febtober household overnight.

So as mentioned, yesterday I replaced the zone valve motor, which had no effect. So the next thing I tried was bleeding the lines. The pipes clang and bang loudly when the heat kicks in even under normal circumstances, so I figured it would be a good idea to do this regardless.

The instructions I followed said to shut off the valve on the return pipe that's just after the spigot, then open the spigot and let the water drain into a bucket. There are my return pipes. The one at the bottom which has the water hose connected to it is for the downstairs zone, which is the one I'm having the issue with. Then there's another spigot right above that in the center of the picture, then in the top left of the picture is a third spigot.

I am curious why I have 3 sets of valves and spigots if I only have two zones of heat? Anyway, I decided just to go ahead and purge all of them while I was at it. With the top two zones, I shut the valve off, then let the water drain via the spigot. There was tons of air in both lines. Also, the air never stopped coming out. I drained out six full 5 gallon buckets from each zone and air was still coming out. Is that normal?

Also, when I went to drain the bottom-most pipe (for the first floor), no water would flow from the spigot while the valve was closed. The valve had to be in the open position for water to drain. The instructions specifically said the valve is supposed to be shut, and indeed it was shut for the other two zones. I don't know if that's important or not.

After draining six full buckets from each zone, and still having air come out, it was getting late and I called it quits. I started the system back up, but still was not receiving any heat downstairs. I had to get to bed, and figured I'd tackle it again later today.

So this morning I wake up and can hear water running through pipes, which is odd. I get downstairs and can hear hissing and gurgling coming from the area of the baseboard behind a couch, which is... odd. Then I notice my socks are soaked through, because surprise, the whole carpet down there is soaked. Apparently somewhere in the baseboard sprung a leak and had been leaking water for a while. I didn't have time to move the couch to take a look at it, but I shut the valve in the utility room which stopped it.

At least the water that was coming leaking out was hot..... I guess that's a silver lining?

We have had below freezing temperatures here (Long Island, NY), but as far as I can tell, the pipes never exit the house. From the boiler in the utility room, they go down into the ground. I'm not sure where they come back up, but I guess it's where the baseboard starts on the other side of the wall. The utility room stays warm since that's where the boiler is, and even without heat, the downstairs never dropped below the low 50's.

I'll move the couch when I get home later to get a better view of what's going on back there, but I think I may just end up calling a plumber. I can't figure out what's going on.

 

Water didn't come out of spigot with valve closed because you had a frozen pipe that didn't allow the water to circulate which is why I suggested checking your pipes.

By opening up the ball valve you allowed water to backflow from the boiler to the spigot. You were just draining the boiler.

When you remove the couch you will most likely find a split pipe. When water freezes it expands and will split the copper. Then when it thaws is when it leaks.