Basic question - multiple radiators individually controlled

drosner

Hi all - I'm adding a bedroom and bath to an existing house and the plan is to use one of the existing hot water heating zones. For whatever historical reason way before my time this zone is only feeding 1 room right now so we believe adding the 2 rooms shouldn't be a problem.

Here is the challenge...these 3 rooms will all be on the same tstat but they will have drastically different heating preferences. In one room (my son) it literally can stay off the entire winter with a few exceptions here and there. In the other room (new master) I'd prefer to have it somewhat on the colder side. And in the bath we like to crank it and keep it nice and toasty all the time.

So I figured I'd put the tstat in the new bath and get some sort of valve like I think I've seen in Europe that controls the flow of water through each radiator. My sons room he just keeps it off, in the bedroom I turn it down, and in the bath it's on full and set the tstat to keep that room comfortable. On super cold days I can manually turn up the bedrooms to full at the radiators themselves.

Is this then as simple as having the plumber put Some sort of three way tee on the pipe that come s up from the boiler - splits the supply three ways - or a manifold of some sort? Anything else I'm not thinking about that will go wrong?

HVACNUT

Can you post some pics of the boiler, standing back a bit, and from different angles?
Then we can get a better idea of what your options are.

And also dimensions of the 3 rooms.
A proper heat loss should be done to know how much heat is needed in the master bed and bath.

Where is the thermostat now?
Maybe we can help with your sons room as well, but we need more info. The more the better.

Gordy

Pipe the radiators homemrun to a manifold. Then use trvs to control each radiator individually.

drosner

Thanks for the replies.....so a simple manifold at the top of the home run then the three individual lines go from there? If the tstat is in the bath and not calling for heat but one of the other rooms trv opens up because it's cold it won't get heat. So I guess it's a delicate balance I'll have to play with.

I'm away from home for a few days so pictures will be tough. It's a pretty modern setup of a 40k btu condensed gas boiler (munchkin) with residential hot water tank fed from boiler. I've got 6 zones with circulator pump - 2 of which are radiant floor. Everything works just fine for the 2 years I've been there.

Bedroom 1 is 100 sq-ft with 2 windows and low ceilings. Bedroom 2 is 150 sq-ft with a cathedral ceiling and lots of windows facing east and south - 7 windows I think. The bath is 75 sq-ft with 4 windows.

Every hvac guy I talked too doesn't do a heat loss - they say they just put baseboard on all the exterior walls and call it a day....

Gordy

There are some calculations that need to be made of course. You need to find a more cognitive pool of hvac professionals........

EBEBRATT-Ed

If they don't do a heat loss........there just plain dumb.....but they think their smart.

@Gordy has the best idea. a manifold with trvs. Especially with different loads in different rooms

Gordy

A side note. Size your emitters of choice. for lower water temps to achieve condensing most of the heating season.

Panel rads have great benefits in fast response, and sizing for different water temps.

Paul48

Six zones off 40k. I wonder how much condensing it does?

Gordy

I would hope. Two zones are radiant floor.

Rich_49

Paul48 said:

Six zones off 40k. I wonder how much condensing it does?

Paul ,
Please don't take this question the wrong way . Would you agree that panel rad systems with TRVs are really nice systems ?

I cannot get past the fact that everyone is so opposed to zoning , in whatever way it is done . Do most contractors just design for first cost and efficiency ?

Weren't many of us taught to sell and design for comfort ?

It is our task to make systems that are actual systems , not just a collection of parts with some of them performing at the highest levels . 6 zones , 16 zones , does not matter , if you design for comfort , efficiency will always follow . We have to find balance in our designs and offer the best advice .

Think of storing BTUs . Maybe a bit more math is required than what we have historically done

HVACNUT

@drosner. Do you enjoy the radiant floors you have?
You can add 2 radiant zones for the master bed and bath, and add additional baseboard to your sons room. Or maybe move the thermostat to his room, if if wouldn't make the other rooms too warm.
Adding more radiant will aid in condensing.

Gordy

Skip the baseboard a panel rad is more elegant than a perimeter of baseboard.

Gordy

I will never argue radiant if cost effective.

Rich_49

Size the panel rads for the radiant temps you are using . Cheaper and still condenses

clammy

Have to agree w rich .I have a munchkin and panel rads and a max temp of 135 and it works excellent .It s not the easiest of sales to most consumers but there are a few here and there but in general not many as i always see mountains of baseboard going out supply house doors and a panel rad is kinda unheard .In my eyes panel rads are easier to install on the end game over baseboard if it s roughed in and supports are in the wall to mount to it s a breeeze and the zoning w them is already done for you w a trv a thing of beauty .peace and good luck clammy

drosner

I love my radiant but I've priced the extension with the assumption that we would use the existing zone upstairs. I can't mix baseboard and radiant on the same zone right?

Sorry guys - I consider myself a pretty serious heating nerd but not sure what you mean by "condensing" in your comments. I get the concept of a condensing boiler - or i thought i did. How does the way I layout a zone impact "condensing"?

Otherwise sounds like a simple manifold and trv's are the way to go...

Gordy

Reference to emitter choice, and sizing for your project. You have a condensing boiler, and radiant already, so size new emitters to use that same water temp.

Gordy

A condensing boiler only condenses below 130*. Size emitters for a 20 delta so 150 supply to emitter.

Paul48

@Rich
I just got home, and responded to "Circulator Flow" before I read this. That response speaks to this. I'm not opposed to zoning, but I think the mod/con manufacturers could do a lot to help the better installers out. They seem to be making advances too slowly.I know..............they are still out-pacing the vast majority of installers, but you can't dumb it down for the ones that can't even install a simple boiler correctly.