Can I add a zone valve?

Hey all, so as a few of you have seen in my posts, I'm heating my whole house (1700 sq ft, two story) with one zone. Unfortunately, it gets pretty hot upstairs when it might still be cool downstairs ( 78 / 70 ). Rob had mentioned the 'stack effect' (I think he called it) and so I've been keeping the upstairs doors closed and this has helped a little bit.

My boiler will always run if the circulator is running, finned baseboards, entire house, and as was posted here per 3/4" pipe max length is 67', I figure at least 80' or more, which makes me think everything coming back to the boiler is pretty much cooled down a good bit, I think it's making it's way thru the t-stat room last

Here's a very confusing diagram for you to ponder. My house is very simply eight rooms, four stacked atop four, roughly the same size, perfect cube shape.

All the balancing valves are pretty well fossilized (and I daren't move them!) so my idea was to add a zone valve (until summer when I can properly do this) to the point marked (A) on the downward return.

This drawing is mostly accurate, I'm not 100% sure on the far right section where it goes to the 2nd floor but I imagine that probably isn't crucial to the issue at hand here, either way, that t-stat room doesn't get the kind of heat the upstairs does.

Your advice please, and remember, this is just a temporary fix so I can sleep at night and not freeze in the morning!! My son's room faces south, is the smallest and has a good run of baseboard, on a sunny day it can peak into the 90's in there with the thermostat set to 74!

How hard would it be to split the one loop into 2 zones? One upstairs and one downstairs, each with their own thermostat? That's what I would do with it..

Is the room with the thermostat an addition?

Have you closed the dampers on the upstairs baseboards?

They have thermostatically controlled valves for hot water similar to the steam ones that do not require power.

I installed these on exactly the same type of setup you have. In my case it was to prevent excessive heating of unused space so I have them set down low, they have worked great for many years. I can't say how well they work as far as keeping temps precisely but they will certainly restrict the amount of heat going into a space.

Post by Richard S. - Limiting Heat in Split Zone. Themostatic Valve?

That particular product is discontinued but I'm sure there is a replacement.

You could do what Richard did or cover the top of the baseboard fins to limit the air flow from the normal eletrostatic charge created by the baseboard to create the flow of air to carry heat.
Do your baseboards have covers that fold over the fin tube? that would be easy to do by just pulling them down.

stuffing a small herd of old towels or sheets in the opening will do this quickly for you.

Richard S. wrote: ↑

Tue. Jan. 18, 2022 3:59 am

I installed these on exactly the same type of setup you have. In my case it was to prevent excessive heating of unused space so I have them set down low, they have worked great for many years.

I don't understand.. wouldn't those valves slow down the whole loop??

Lightning wrote: ↑

Tue. Jan. 18, 2022 7:35 pm

I don't understand.. wouldn't those valves slow down the whole loop??

If the whole loop is in series, yes. In this case, it is actually multiple loops that are supposed to be balanced via balance valves. Throttling flow on the upstairs loop should not reduce flow on the first floor.

Personally I would close the dampers on the upstairs radiators and put aluminum foil on the fins if needed to cool things off, and run it that way until spring...then install a zone valve for each floor.

Rob R. wrote: ↑

Tue. Jan. 18, 2022 7:44 pm

it is actually multiple loops that are supposed to be balanced via balance valves. Throttling flow on the upstairs loop should not reduce flow on the first floor.

Ah.... thanks for clarifying.. "I see" said the blind man, as he picked up his hammer and saw..

Lightning wrote: ↑

Tue. Jan. 18, 2022 7:35 pm

I don't understand.. wouldn't those valves slow down the whole loop??

There is two zones but each zone is basically setup like this, the "valve" is the thermostatically controlled valve.


To elaborate a little it doesn't have degrees on it but numbers, there is corresponding chart with approx. degrees. I just keep it at number that corresponds to about 55 degrees since that space is not being used. The lowest setting is for keeping the pipe from freezing.

That looks like a good place for a zone valve, but we have to think about your amount of piping being cut in half when it is closed and what that might do to your flow rate and pump.

What make/model circulator pump are you using?

Before any changes to the plumbing, need to make sure it will not upset your pump

PS- That's a pretty good drawing. You should see what some of us put up at times

This has been working quite well for about 6+ years now. I wish they were installed 30 years ago, I used to stay here some nights when I had a little bit too much to drink. Gram of course would be up with roosters and I'd wake up in the Sahara. Too much radiation in the room I was using but overall the upstairs was always too hot.

There is two "old" B&G's, not sure what the models they are. Old is is quotes because one of them was 30 years old brand new in a box. I have two newer and smaller pumps sitting on the shelf.

It's neither here nor there, it's all getting changed in the very near future. This is fairly large duplex, with 7 rooms each side. What I'm going to do is turn the upstairs on both sides into my pad and two apartments on the bottom level. Nothing has really een done to this house since the late 60's or early 70's. Full tear out and renovation top to bottom but I'll need to do it chunks.

As far as the drawing goes I can manage....

Just some food for thought. I had (past tense) zone valves on several zones in my house. Hated them. They were noisy and if one closed while circulator was still running it would hammer the loop something awful on closing. I ended up pulling the zone valves and installed a seperate circulator pump on each zone. I used the small grunfos circulators but your mileage might vary. Very quiet system now, no pipes rattling and overall much better than before. Since you have to cut into the system anyways, my advice would be to go this route.

leward wrote: ↑

Tue. Jan. 18, 2022 10:52 pm

Just some food for thought. I had (past tense) zone valves on several zones in my house. Hated them. They were noisy and if one closed while circulator was still running it would hammer the loop something awful on closing.

The ones I listed above are 100% mechanical and make no noise, AFAIK they also slowly open and close so there is no possibility of water hammer.

I can't really say one way or the other how precisely they keep the desired temperature and I'd imagine it's not as good as a wired thermostat but they have worked really well for what I needed them for.

leward wrote: ↑

Tue. Jan. 18, 2022 10:52 pm

Just some food for thought. I had (past tense) zone valves on several zones in my house. Hated them. They were noisy and if one closed while circulator was still running it would hammer the loop something awful on closing. I ended up pulling the zone valves and installed a separate circulator pump on each zone. I used the small grunfos circulators but your mileage might vary. Very quiet system now, no pipes rattling and overall much better than before. Since you have to cut into the system anyways, my advice would be to go this route.

That usually happens when your circulator is the wrong model and/or does not have a differential pressure bypass installed.

i.e. You have a circulator sized to provided adequate flow when all zone valves are open. If only one zone valve is open the flow rate will be quite high, and cause pipe noise when the zone valve closes.

There are a few ways to avoid this.

1. Install an appropriately sized circulator on each zone, like you did.
2. Use a circulator with a pump curve intended for zone valves and install the bypass mentioned above.
3. Use an ECM circulator that varies its speed based on how many zone valves are open (that is what I have).
4. Use heat-motor type zone valves that open and close slowly.

Installing the zone valves on the return will also reduce the chance of any pipe noise. I know a lot of people prefer to have a circulator on each zone, and that's fine - I just wanted to point out that zone valves can work very well if installed correctly.

Rob R. wrote: ↑

Mon. Jan. 17, 2022 9:02 pm

Is the room with the thermostat an addition?

Have you closed the dampers on the upstairs baseboards?

No, it is not an addition, but unfortunately it does have the front door and stairwell in the room, the opposite corner of the house has an enclosed porch that is a pretty gnarly heatsink and will be attacked this summer.
As far as dampers, I did close all the upstairs and I have noticed a good difference. Sadly, -3 Sunday morning gave me the 7deg differential between floors. If the weather stayed above 20 I don't think it would be super noticeable, but once the heat really needs to be in one place...it isn't lol.

CoalisCoolxWarm wrote: ↑

Tue. Jan. 18, 2022 9:56 pm

That looks like a good place for a zone valve, but we have to think about your amount of piping being cut in half when it is closed and what that might do to your flow rate and pump.

What make/model circulator pump are you using?

Before any changes to the plumbing, need to make sure it will not upset your pump

PS- That's a pretty good drawing. You should see what some of us put up at times

It's a Taco 007, I just measured and there is 57' of finned section downstairs and 58' upstairs, not to mention all the piping in between that isn't finned. My long term plan is to leave the upstairs baseboard in and put in radiant floor this summer, doing research on that now.

I have read about the thermo controlled valves, which seems viable..unfortunately I happen to have a zone valve my brother in law gave me...I have another taco circulator too, but since I wasn't looking for a long term solution I thought wiring it up would be a little more involved. Good point on the noise when opening closing...I would definitely have to look into (though not sure how) if the zone valve I have is the right one.
Thanks for your input everyone! We'll see what happens when it gets cold again...which won't be long!