4-zone hydronic radiant heating system

Julien

Dear forum members,



I am trying to understand the heating system in my house, and logic is falling short at this point.  Let me preface this by saying I have no formal training in heating systems, so this may be a very easy question for some of you.



There are four zones in the system (four thermostats in the house). My main hurdle lies in understanding the piping at the level of the motor controlled valves that are linked to the thermostats. I attached a picture to this post (one of the valves is missing, but this is not the crux of the question). So, the arrows on all valves point in the SAME direction, towards the bottom of the photo. All valves are connected to each other (with the pipe at the bottom of the photo), and that's it. Now logic would dictate that there should be a return line branching off from this pipe that connects the four valves, returning water to the heater; but there is no such line, meaning that water does not have anywhere to go even when the valves are open. I DO NOT UNDERSTAND how these valves are useful for anything in the current circuit. Clearly I am missing something, and this is a clever installation trick of sorts (the heat did work well at some point...). Any hint?



I hope the description is clear enough, if it isn't I'll draw it out.

Thank you for your help!

- Julien

Mark Eatherton

Oy...

The picture isn't indicative of a properly installed system. No common return back to the heat source…



You're going to have to draw it out, showing the heat source, heat emitters etc.



ME

Ironman

Unless...

The last valve with no actuator is actually the return?

Julien

alright, so I'm not *completely* stupid...

I do have one detail to add : I'm pretty sure that the three left valves are closed by default (meaning, if I remove the motor part), whereas the rightmost valve is open by default. At some point I thought "eureka!", the rightmost must be the common return, and the valve allows some central control on the whole system. However, the arrow on that rightmost valve points the wrong way... can water flow the wrong way??



I'll draw it out when I can (but the problem is that a lot is unobservable...; I'll see if I can find some sort of blueprints)



Thanks,

- Julien

Ironman

Installer error?

The installer may have come to realize his error and correct it by removing the actuator.

Julien

the actuator got broken a month ago when water heater was changed

this is a separate problem that needs to be fixed. In the meantime, I can leave it always open (or close it manually with a penny and some duct tape...).



but what bothers me most is the direction of flow indicated on the rightmost valve, which is opposite what it should be if it were the common return. Can water still flow in the "wrong" direction?

Zman

Road to nowhere

If the system has worked in the past there must have been reverse flow.

Yes, zone valves will allow reverse flow. It is often more noisy.

A drawing is needed.

Carl

Mark Eatherton

Corn fusion...

Yes, a valve can be installed backwards, and in some cases, will BANG when closing if other zones are still calling.



Part of the confusion is that you said you have 4 thermostats in the house, which requires 4 zone valves, which is what you have.



Now, the direction of the arrows is relevant, but without seeing a full drawing of all components, it is hard to say.



I've never seen a "master" zone valve, although I can see how a DIYer might throw one in if he is realizing ghost flow due to immersed coil for DHW production, but it sounds as if that;s not your case because you mentioned a separate water heater.



I guess it is possible that two thermostats could be calling on one zone… How the comfort levels in the home? Before the accident? After the accident? Have you physically tested all zones to make certain that they function when called upon?



Let's see what you come up with in the way of a schematic before we start condemning anything/anyone.



ME

Julien

I'm confused too with the 4 thermostats

indeed, I find that having 4 thermostats and 4 valves seems like a no brainer, but the absence of a common return in that case and the fact that one valve is of a different type than the others (open by default) makes me think that it must be the common return... (which leaves me with one thermostat that I don't know what it should connect to - and having two thermostats control one zone seems quite silly)



I will try to continue investigating and map out the whole circuit - but I guess that once I have that, I will probably understand everything...



Can you give me pointers on physically testing each zone, other than manually opening one valve at a time and waiting to see which pipes get hot and whether the floors get hot in that area of the house? I haven't been terribly successful with this thus far (floor are concrete, it takes a while!)...



I'll at least take a few pictures and draw out what I see of the installation, I'll get that posted here by tomorrow. What I was initially hoping for with this thread was that there was an easy answer to why 4 valves were installed as they are with no obvious return line, but clearly things are not simple...

Mark Eatherton

The ooohh aahhh test...

Have someone else turn the thermostats up one at a time while you are near the zone valves observing, and feeling (carefully) with your hands.



You should be able to feel some difference (cooling first, then warming) as fluid flows through the piping. This will give you an idea as to the actual direction of flow.



I can;t identify those valves visually, so I don't know if there is an indicator showing when the valve is open versus closed. Maybe someone else can ID them.



ME

Julien

a wild idea

An idea occurred to me. What if one zone is prioritized in this (rather big) house? Meaning, if the zone needs heat, it closes the return valve for all other zones (the rightmost valve), AND opens a valve somewhere else (I haven't found that valve yet, but I'll look everywhere for it...). I could imagine that the master bedroom could be that "prioritized" zone. Have you guys ever heard of such an installation?



By the way, I really like all the creative titles on this forum!



Thanks again,

and I WILL post drawings and pictures when I'm home.



- Julien

Julien

dessine-moi un mouton....

Dear heating helpers!



I spent a couple of hours with my radiant heating system yesterday and came up with a simple drawing of what I can see (attached).



I also have a few observations; with the heater running:



With all valves in their default mode, the pipe that goes up, on the left of my drawing, with a filled arrow, is hot (all others are cold, except for the one right next to it which is a bit warm, but this could be because it is next to a hot pipe...).



* if I close 1 (by pushing the pin in), nothing seems to happen

* if I open 2 only, nothing happens

* if I open 3 only, nothing happens

* if I open valve 4 (in manual mode), the pipe where I wrote "if 4" gets hot

* if 4 is open, and I open 3, the pipe "4+3" gets hot

* if 4 is open, and I open 2, the pipe "4+2" gets hot

* if 4 is open, and I push the pin on 1, nothing happens that I can observe

Finally, after a whole night of running 4+2, I still don't detect any heat in any of the other pipes, nor do I feel heat in any of the floors yet (but they are all concrete floors, it could take a while I guess...).



Let me know if you have any thoughts so far, and I will continue my investigations. Right now I have 4+2 running, and perhaps something will be warm by tonight...



- Julien

Julien

maybe you need to know this:

the room where the heating pipes are is at level 3 of the house, the same level as the master bedroom. There is one level up (level4) and there are two levels down, of course. Each level has a thermostat.

Just to put things in context - and maybe pipes going up or down relate to which zone they are serving (one would hope!)

Julien

update, scratch previous drawing

so it's starting to look like 4 is the common return, as the other valves don't do anything if operated by themselves. Does this seem like a "kosher" design?



I still haven't been able to detect any warmth in the pipes where the valves are attached... which seems weird to me.



But with the setting 4+2, master bedroom floors got nice and warm after about 12 or so hours.



Now running 4+3 to see what happens.



I'm sorry I'm just thinking out loud on this forum, perhaps I'd better take it offline and come back in a week or so if I still haven't figured it out?

Ironman

Heater?

Is your "heater" a boiler or an instantaneous water heater? If you're not sure, give us make and model.



Your drawing doesn't completely show where the pipes running upward go. How about some pics?

Mark Eatherton

Sounds like …

4 is the supply, though I've never seen anyone put a valve on a main supply. Could also be that 3 is air bound, hence no flow.



It is entirely possible your valves are all on the supply, not the returns.



You're still missing a whole bunch of the critical parts of this system, and the drawing, though helpful, is not complete enough to connect all of the dots.



Look in closets, for small access doors. That is where manifolds are typically hidden.



In regards to your prioritization theory, possibly, but not seen in my 30+ years of looking at and working on hydronic systems. Not to say that someone (unknowing DIYer) couldn't do it, but why would they do that?



Keep looking and you will eventually find the other half of the system.



ME

Julien

new condensing tankless

the "heater" was just installed. It is a condensing tankless water heater, the Noritz NRC1111-DV. Previously, it used to be a big tank heater.

Here is a picture of the visible system - two pictures actually but I stitched them together quickly.

Ironman

Oh Boy, Here We Go Again.

That's definitely the wrong appliance for space heating. It's designed, controlled and approved for domestic water heating. It appears there's a second one to the left. Is that connected with this one?



If this unit is tied to both your domestic and space heating, you have the potential for serious health and system issues. Not the least of which is Legionella.



The piping is so convoluted that I can't follow it from the pic, but if this is an open loop, that would account for the problems youre having.



I would suggest getting a REAL hydronics pro to look at what you've got, not the hack who did this.

Julien

closed loop

There is a separate tankless heater for domestic water heating.

Why is this heater not appropriate for radiant heating? Is a tank water heater recommended, and why?

I will have a professional look at it soon - but I do like to understand how it was supposed to work initially, when it did.

By the way, 4+3 heats the family room.

Ironman

Why?

Because it's a DOMESTIC water heater, not a boiler.



It is not designed, controlled or approved for space heating and probably now has no warranty because of its mis-application. It probably won't last 3-5 years.



At the moment, I don't have the time or the inclination to go into a long dissertation on the particulars of why its wrong; I've done that in several other posts and so have others here. You can search the site and find them.



A little bit of common sense: if a tankless water heater could take the place of a boiler, there would be no need to make boilers.



The decision to use a tankless is driven by two things:

First, the amount of mis-information dissimenated mainly through Internet peddlers and hacks.

Secondly, man's nature to try a get something for nothing or less than what it's worth.



The first preys upon the second and finds more than an ample number of recipients for its wares. These folks sooner or later come to realize that the laws of physics will out-weigh the laws of economics - every time.

Julien

stepped onto a sensitive subject here!

thanks for the mini-blurb.



Yes, I'm sure my feather-in-law had this installed because it was cheaper than getting a boiler, and he thought it was "the best" (in his words). I will look into changing it back to a boiler, and having him use this tankless for something else.



Now that this is cleared, let's get back to the main problem: I have now determined that 1 controls heat to the downstairs bedroom, 2 controls heat to the master bedroom, 3 controls heat to the family room, and 4, right now, acts as the common return for 1, 2 and 3 - 4 needs to be open for any of 1, 2 and 3 to get heat. Although the wires from the upper floor thermostat come into this heater room, it is clear that they should NOT connect to 4 in the current configuration, because that would just make no sense. 

I'm going to talk to the guy who installed this tankless a month ago. He was not a radiant heat professional. Perhaps he made a mistake when he piped the new heater in. This would explain why the current configuration is not logical and why I've been getting headaches trying to figure it out - hack it back to a functional state. Logically, what we need is a common return that is not controlled by valve 4, so that when 1,2 or 3 needs heat, they can get heat independently of whether zone 4 needs heat...



I'm sorry that my posts have been confusing, but I appreciate the little snippets of help and wisdom that you have posted thus far.



- Julien

Julien

just keep looking, just keep looking

Thank you Mark, I will investigate closets when I get back into that house...

(and I don't think that 4 is the supply, I am now actually pretty sure that it currently serves as the common return).

Ironman

Heat Emitters

What type of emitters do you have? Baseboard, in floor, staple up, slab?



Not sensitive about the tankless, just tired of seeing people being ripped off by hacks and Internet peddlers. This topic comes up every week on here. There's a long post from last week on the "main wall" that's entitled "How Prevalent is This" that's deals with this.

Snowmelt

Zone control board.

The picture isn't really that good here is what I would do.



Go to a plumbing supply house and order a 4 zone control board from taco, if you want look online for how it works first.

I will assume with 4 zone valves you either have 2 , 4 wires 2 red and 2 yellow .



The zone board panel you will supply 110 volt to operate,

Each zone would be numbered, so take any one of those zone valves and t-stat wire and install the t-state wire in the top where there are two smal screw lugs and the zone valve on the bottom of zone 1 in the proper screw lugs.

Repeat for all 4 zones.

Then the 110 volt pump will go on a 110volt normally open screw lugs follow the c for common and n/o for normally open.

Sounds more complicated then it is. Now when ever a specific zone calls for heat you will be able to see a light for that's pacific zone for both t-stat.

It's a good trouble shooting tool so I highly recommend it.

About using a tankless, if your using a low temp application 140 and below it will work fine but not the best application in the world. I would you primery secoundary so that's two pumps, also instead of that air scoop I would use a air seperator. My primery pump would be a 009 or a 26-99 my air seperator would be a taco 4900.

As a new product that I never installed yet I would put a caleffi hydraulic air separator with dirt and magnet.

Julien

don't know right now...

It's becoming clear that I need to contact the architect who hopefully will have the plans for the radiant heating system...

Anything specific you have in mind when asking this question about the heat emitters, Bob?

- Julien

Ironman

Yes

A radiant floor can become air bound and can be difficult to purge if you don't have manifolds with flow setters and purge valves. Baseboard radiators can become air bound too but generally don't require as much apperatus, especially if they're looped in series like most are.



So, do you have baseboard rads or radiant floors, or both?

Weezbo

excuse me for coming along late,...

Here is my SWAG , or Scientific wild a$$ Guess,

Mark is correct .

Here is how i suppose it once "Worked" ,



there is a pipe that goes both UP and down on what may be described loosely as the supply and return.

up stairs some place is another field installed Zone valve , and return header tied to the return .

these zone valves have one thing in common none of them will work unless there is a way back to the boiler ,

hence they have something of a slave relationship to the one valve.

the one upstairs zone valve that you have yet to find , may allow for circulation, this is not quite clear, either, at the moment.

Although it has better than a 50 50 chance it does ...lol

the heater on the 90 out from the one we are viewing seems to be somehow connected to this , therein is another rather disproportionately large variable .



perhaps you need to be looking for One more Tstat , as well as the mystery zone upstairs with it's return ...

by the way , just because it follows no real logic does not mean we cannot think it out , it just means when ever new "Variables"

and discoveries are made our opinions and hypothetical meanderings may change to finally derive exactly what is happening ,

anothe picture of the heater 90 degrees adjacent to this one and perhaps the hidden field header / separate zone valve may give us further insight .

At the moment i would say that none of the individuals who answered you , including myself , would do this to your materials.



I hope that helps .

*~// : )

Julien

there may be no solution with the current piping

... and an easy solution with minor re-piping



I learned a couple of days ago that the person who installed the new heaters re-did a lot of the piping, so my initial assumption that the system should be functional "as is" was likely wrong.

I am now fairly sure that they simply made a mistake (or two) in the piping. I think the 4 valves do (should) correspond to the 4 thermostats, and that they also should flow in the correct direction. So what is clearly missing is a common return, cf the very first post in this thread... With the common return piped in, and another return removed, I think the system will be functional and logical again.

A lot of wasted brain matter...

 -Julien