QUESTION FROM Matt

I have 4-zone baseboard heating in my home and I am doing some remodeling in the basement which will require moving the piping for only a single zone. There are so many knobs and valves to deal with. How do I drain a single zone, and then once the remodeling is done and the baseboard pipes replaced, refill that single zone.

Thanks for the help.

ANSWER FROM HOME-WIZARD

Dear Matt:

If you haven't already, you should look at our online video tutorial on baseboard heating systems: http://www.home-wizard.com/Baseboard_Heating_101.asp At about the 6 minute point it in the video it begins to describe how to drain and re-fill each of your heating zones. Now if your question is "how to determine pipes and valves around your boiler go with which heating zone," then what you can do is turn off the thermostats for all four zones. Wait for a while to allow time for your system to cool down, and then turn on just the thermostat for your basement. Then look at the piping around your boiler and note: 1) which circulation pump comes on, and 2) which return pipes coming back to the boiler start to heat up. This will be the piping and valves that you will want to use to isolate, drain and re-fill for your basement heating zone.

Hope this is helpful.
Home-Wizard.com

FOLLOW-UP FROM Matt

Thanks, the video was helpful in beginning to understand the workings of the system as well as the steps to drain each zone. However, I noticed some large differences between my system and that of the video: 1) I seem to have only one circ. pump serving all the zones; 2) I cannot find the auto pressure relief valve, only a drain spigot; 3) I can find isolation valves on the return end for only 2 of the zones (is this even possible?); 4) I cannot find anything resembling the auto water makeup valve, only a turn-knob on the inlet water supply which if i turn i hear water flow and see the pressure rise. Am I totally missing everything?

ANSWER FROM HOME-WIZARD

Dear Matt:

Glad the video was helpful. As you can tell, it describes a "generic" baseboard heating system, and each one is going to be a bit different in each home. It's difficult to diagnose your system without being able to physically see how it is configured.

But regarding your questions, I will take each one at a time and offer what I can:

1) When you said you have a four zone system in you house, do you have four separate thermostats? If you really only have one circulation pump, and four heating zones, then you would also need to have four motor-operated valves which would be controlled by the four thermostats.The problem with this type of setup is that when only one zone is calling for heat, you would have the full force of the circulation pump (which would be designed for all four zones combined) operating for just one zone. But again, let's first figure out if you indeed have four, or just one heating zone. And if you do have four thermostats, then can you then locate the four circulation pumps that your system should have.
2) You system must have a pressure relief valve somewhere on the system. This is an extremely important safety feature. Start by looking at where the pipe first comes out of your boiler, and look for any place where the line could tee off for a small valve with a lever on the top of it, with a small discharge pipe coming off of it.
3) If you do have four separate heating zones, then yes, it would be very unusual to not have isolation valves on each zone.
4) It could be possible that you do not have an auto-makeup valve to bring fresh water into your system.

Hope this is helpful.
Home-Wizard.com

FOLLOW-UP FROM Matt

Thanks for the response. Yes I understand it is very difficult to diagnose without actually seeing my system, and I appreciate all the help. 1) Yes, there are 4 separate thermostats. A single pipe exits the boiler, passes over the expansion tank and splits into 4. Each line the has a Taco zone valve before running through the baseboard units. Each line then returns to near the boiler, merges into one line and passes through a Taco circulating pump. 2) I found the relief valve on the top of the boiler with a drain pipe directing flow down to the floor. It looks like the picture at the top of this site (http://www.inspectapedia.com/heat/ReliefValves.htm ) rather than the one in the video. 3) I am at a loss to find the isolation valves on two of the zones. On two zones the valves are located directly below the purge spigots and above the joint and circulator pump, but on teh other two there is nothing. 4) Is there any potential issues with only having a straight on/off knob instead of an auto-makeup valve for fresh water?

ANSWER FROM HOME-WIZARD

Dear Matt:

Regarding the two isolation valves that you haven't been able to locate, does it look like it would be possible to drain the zone you need to access using one of the two isolation valves that you could find? In other words, does the piping configuration allow you to isolate and drain two zones rather than having to drain the entire system? And does it look like this will allow you to do what you are trying to do? And regarding potential issues with not having a auto-makeup valve for fresh water, it just means that you will have to watch your system, and if the pressure gets low you will need to add water by opening and closing the valve manually.

Hope this is helpful.
Home-Wizard.com

FOLLOW-UP FROM Matt

Yes, as luck happens the zone i need to drain and move is one of the two where i have been able to locate the isolation valve. So all i need to do is close the isolation valve for that zone, open the zone valve, and then open the drain valve to empty the water? Once empty i assume i should then close the zone valve as well to keep it empty while i move the baseboard units? Regarding the auto-makeup valve, with further research it turns out i actually have one, it is an auto-water feeder built into the expansion tank and is visible as a brass assembly on top of the tank and below the air purge valve. With this, will I need to use the manual valve to refill the zone again or will it be done automatically once i open the zone & iso valves?

ANSWER FROM HOME-WIZARD

Dear Matt:

Regarding specifically which valves you are going to need to open/close, it is very difficult to say specifically without actually seeing your particular system. But it sounds like you are on the right track. Regarding your auto-fill valve, depending on the particular valve that you have, you may find that you need to manually lift a lever on it, if you want your system to rapidly re-fill.

Hope this is helpful.
Home-Wizard.com