Troubleshooting HW baseboard

AboveMe

I am at such a loss and hoping to get some creative guidance. I have a baseboard radiator that is not getting warm. All others in the house work.  Here are the details:
Hot water boiler system, 3 stories, column radiators on two floors and 1 baseboard radiator (the one not working) on the 3rd floor. 
While learning as I go, here's the order of things done over a series of daily attempts: I bled 2nd floor rads, then boiler in basement, then third floor; then back to bleed 1st floor, then back to second and third floor. All column radiators work great. The one baseboard doesn't come on no matter how high I increase the temp. From reading other posts, The boiler pressure is about right at 12-15 psi. 

I feel so defeated right now because I truly think that it's something so simple that I'm just missing. But all the radiators and boiler have a steady stream of water when bled from the valve. Still, the one baseboard radiator will not heat. 

I wonder if I should repeat bleeding, in a different order (I didn't know better before) or if there's something else that I could try before calling an expert (hard to find - waiting on 3 plumbers who have yet to show up).  I appreciate the help. 

AboveMe

AboveMe

Jamie Hall

12 psi may not be enough. Depending on the piping configuration, even 15 psi may not be quite enough. When you open the breeder on the third floor, you should get a good stream of water. Not a fountain, but at least a good stream.

hot_rod

Your fill valve has a fast fill lever on it, are you using that.
With just 12 psi you may not be getting enough flow to push an air bubble around

EBEBRATT-Ed

Looks like you ran the pex return line under the fin tube. Not the best way as it could obstruct some air flow but that is probably minor. I would have used copper return run on top of the fin tube is where it should be until you get out of the enclosure.

Depending on where the bleeder is on the baseboard that could be part of the issue.

If you have valves on other radiators close them and see if that will force the bubble out.

As others have noted 12 psi may not be quiet enough for 3 floors.

You will get their don't be discouraged

pedmec

if your not getting any air out and you have the correct psi set then what you most likely did was create a traffic jam. i don't know how your system is pipe but considering it's a radiator system it's a safe bet that it's a direct return. And if that's the case you most likely piped your baseboard as another radiator. If this is the case then you will have a hard time getting flow because you have created a traffic jam. the cast iron and steel piping is like a wide open highway compared to trying to get flow thru the internal ID of a pex pipe and fittings. Close all the radiator valves and see if you get flow thru the baseboard. if you get flow thru the baseboard then the pex is too restrictive compared to the rest of the system. what i do if this is the case is open up the radiator valves one complete turn to try and balance the flow out. As the winter gets colder and you realize some rooms are colder than others you can open the radiator valves a little more in the colder rooms to increase the room temperature. i have had this issue happen multiple times. contractors love pex they try and use it on everything. you have created a balance issue

AboveMe

Really appreciate the input.

Bleeder valve is on the opposite end of the baseboard (picture shows the end cap on it).

I will try shutting off the other valves and report back.

I have not used the feeder valve. When I bled the boiler, I shut everything off. Once I got a steady stream, I closed the boiler drain valve and opened the line so new water can fill the boiler. But I did not do anything with the feeder valve. 

EBEBRATT-Ed

@AboveMe

Leave the boiler drain shut. Turn on the makeup water. Use the "fast fill" to bring the pressure up to 20psi. With the boiler and circulator off go up and bleed the troublesome baseboard. Bleed it good.

Then start the boiler and turn the thermostat up and see if the baseboard heats. Bleed a little with the pump running if you have to if it heats without bleeding leave it alone.

Then before the boiler gets too hot lower the boiler back to 15 psi. Check the bleeder at 15psi with the pump off to see if you have enough water pressure at the bleeder.

Intplm.

@AboveMe
I dont see a manual purge on any of the pictures.
There should be, at the very least, a manual purge on the return line near the boiler. (looks like 1-1/4 copper tubing.)
If there isn't one, look for one at each of your zones.
If you dont have them, it might be a good idea to install some manual purge areas to help remedy this.
Combining these with a fast feed and not the auto feed for purging is a very good way to purge air out of the system.
Look around in your basement. Trace the pipes throughout and hopefully, you will find some purge valves.

hot_rod

A couple options:
Close the ball valve above the boiler on the supply, put fill valve in fast fill mode, flip the lever.
Flow goes around the system and you could purge some from the boiler drain, not ideal but workable with fast flow.

Easily add a valve between the two ball valves on the return. Press tee in there with a full port ball valve with hose connection.

AboveMe

Hi all thank you so much for the feedback and recommendations. I was able to bring up the pressure, turn up the heat to about 80 and the baseboard radiator warmed up. It was not as hot as the other column radiators on lower floors but it definitely was warming up the room. 

The pressure is currently at what looks to be ~12 psi and with that, the vent on the boiler is releasing some water (noticeable from the long white pipe in the picture) which I assume is extra pressure coming out of the system.

Should I try to bring up the psi to 15?

I'm concerned that I have to keep the thermostat up so high in order to get it to crank out heat. I'm going to leave it like this for a few days and towards the end of the week I'm going to start closing some of the valves and the column radiators to try to balance the heat because as it was the rooms were turning into a sweat box.

Anything else to consider? Thanks very much. 

MikeL_2

  Consider a new gauge, or test the existing gauges accuracy; many of those hot water boiler gauges don't / won't measure correctly........

hot_rod

If the boiler or distribution is not keeping up with the load, cranking the wall stat will not help at all
either the pump in not moving adequate flow or the radiators are oversized for the boiler

It takes time for the system to reach thermal equilibrium, so give it time before you start tweaking

AboveMe

Hi, I wanted to come back here and thank everyone for your suggestions. I have a monoflow system and the radiator in question is on the last tee out of that system. 

I found a plumber who is a real stand up guy, knowledgable and is troubleshooting this with me.  We've looked at possible broken gauges, expansion pumps, etc. We are now going to install a valve between the two pipes that bring water up and the return to see if we can force the water to go up more efficiently. 

I'm sure there will be more, and I really thank you all for your expertise.