I don't see how the zone for the basement could have a frozen pipe if the temperature has not fallen below 50 degrees. It might be possible if the pipe is butting up against an uninsulated wall or very close to a drafty window or door.

Do you hear or feel the circulator pump for the basement zone working? If not then most likely you need to replace the pump. The control board or the thermostat could also be at fault. You need a voltmeter to determine if it is a control or pump issue.

With a VOM meter, check if the basement thermostat is calling for heat (24v thermostat input signal at top of Argo board), then if the Argo board is sending 120v power to the basement pump to run (bottom terminals on the Argo board), then see if the basement pump is actually running or not. This should locate where the issue is.

I looked online at the Argo documentation and it mentioned you can use a jumper and switch to configure a Priority Zone option for heating.

If that option is chosen it will make Zone 1 the priority zone. When Zone 1 calls for heat, all other zone pumps are deactivated. If it runs more than 30 minutes in Zone 1 Priority mode it then apparently turns the other zones on for 30 minutes, and then goes back to Zone 1. It is possible that with this option configured you might not have enough "on" time for the other three zones to heat up to the thermostat set point. The other possibility is that its not properly switching out of Priority mode, so maybe the pumps for the other zones don't ever come on.

The first step I would take is to set every thermostat up to a fairly high temp (80?) so they are calling for heat. Then go to the basement and put your hand on each pump to verify that they are pumping water. If the pumps are not running, you need to figure out if the thermostats are working and what the controller is doing.

Also verify the pressure and water temp for your boiler. My radiator system runs at 30 psi max and 140 degrees max, but I don't know if that's typical. My gauges have movable pointers that the installer moved to those points to use as a reference. If I bleed my system enough that it gets low on water there is an autofill valve that should top it up. However, that same valve has a manual lever I can use to top it off manually until I get up to about 28-20 psi.

Bruce

Dear @mike_home, @formulaross20, @Bruce in Northern Virginia

first of all thank you very much for your advice. you gave me ton of useful information

I will respond to all 3 of you based on compiled information in your posts, hopefully you will find time to clarify a few of my questions:

1. I don't know if the walls are insulated or not. The issue is that the basement is completely finished (walls and ceiling) and i don't know if it's insulated well or at all. Is there a way to find out without breaking walls? Hot water is supplied using red PEX pipes and i can see them as they come out of the walls and into the baseboard heater but i don't know about inside. I really really hope you are right and they are not really frozen inside.

2. There are total of 4 circulator pumps, one for each zone, by a company called Taco and watching Youtube videos and reading about them, they are extremely quiet. At least i cannot hear any of them but i know at least 3 are working since i am getting heat in the other floors. I also can't determine any vibration when i touch the pumps. One thing thing though i am wondering about, the pump on basement zone gets very hot on each side of it, so hot i can barely touch the pipe. But as i move my hand up the pipe away from pump and boiler, the pipe gets luke warm. What does this mean? The pump is not pushing the water? But why is it hot on both ends of it?

3. I ordered a voltmeter on Amazon and hope to have it here soon but unfortunately the weather here in NY got bad again and we got snow blizzard today and tomorrow, and i think i won't see the voltmeter till Thursday.

4. In regards to Argo board, since it lights up green LED for a zone 1 (where the basement is connected) when thermostat is calling for heat, wouldn't that already indicate i am getting 24V? Or not necessarily?

5. There is a switch on Argo board where you can toggle Priority Zone on or off. I read in documentation, if its set to On, Zone 1 becomes priority zone, and if it's set to off, then Zone 1 is just Zone 1. I currently have mine set to off.

6. My boiler is by Crown and i read that pressure should be around 20 PSI or less and when i bled the system i also used Fast Fill valve to fill the boiler.

Maksim

I have a similar system, and each pump has its own light - does yours? I have a 4-zone manifold with the pumps connected to it, I just looked at mine and three lights are on and the piping feels hot on both sides of the pump (as expected); the fourth light is off, and non-manifold side is cooler. Maybe your basement pump is just conducting the heat away from its source; that's why it's warm. It sounds like that pump is not operating.