Troubleshooting Zoning Problem

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Old 07-15-18, 08:02 AM
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Troubleshooting Zoning Problem

I have a 3 story building that I recently converted to 3 zones of cast iron radiators (one zone on each floor). I have 1 pump and 3 honeywell valves on the return lines. The building was built in 1913 with a gravity water system so many of the pipes in the basement are 3". The way that I zoned it was to redo all the radiators on the 1st floor and open the walls to the 2nd floor to drop new returns from each radiator. The third floor was left on the original piping. The system seems to be working OK except that it seems that 2 "runs" to the 2nd floor are being controlled by the 3rd floor? Last time I looked all the plumbing seemed to be correct, but I have to get on it now, before the heating season.

So I though I would start by running the 3rd floor heat, to verify that it is also heating up the three radiators on the 2nd floor as I suspected.

Any ideas on the best step-by-step? I guess if the 2nd floor radiators heat up when either the 2nd or 3rd zones are on perhaps I have ghost circulating?

The plumbing is now behind new walls although all the final runs to the boiler are exposed in the basement. It is easier for me to put valves or whatever in the basement than tear up walls.

I would appreciate any advice on how to proceed.
 
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Old 07-15-18, 04:11 PM
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Hi, be sure the zone valves are closed, then try each Tstat one at a time and see how each zone operates.
Geo
 
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Old 07-15-18, 04:27 PM
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That is what I planned on. I will start with that. I am wondering if I may see circulation even though no return valves are open. Since I just installed the piping on the first floor, I think I can count that out, although I will have to see if I used common supply lines.
 

Last edited by cdrat; 07-15-18 at 04:47 PM.
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Old 07-15-18, 05:23 PM
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You will not have any ghost circulation with zone valves as they are positive shutoffs.

Are you heating the whole second floor or just a couple of rads. If it's only a couple I would look for improperly piped rads on the second floor, connected to the 3rd floor main.

Start by turning up the 3rd floor stat and feel every feed and return coming off the 2nd floor pipe to see how the hot water is getting to the 2nd floor rads.

Depending on your repiping of the rads you may be back feeding to a couple of rads on the way back to the boiler.

If you start with that to see if you can locate the problem then we can proceed with a solution.

Remember all zones have to be completely on their own main lines. Check to see if you have any 2nd floor rads returning or feeding off your 3rd floor zone. If so they must be separated.

Hope this helps a little.
 
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Old 07-15-18, 06:08 PM
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The entire 2nd floor is 6 radiators. The third floor has 7. I was told that I could have supplies sequentially going from the 2nd to the 3rd as long as they had their own valved returns. To be clear, I think I have 5 vertical chases coming from the basement supplying both the 2nd and 3rd floors. I have the original returns being used for the third (galvanized or iron) and new copper returning all six radiators from the second.

So, did I violate the rule of the zones on their own mains?

Does this sound as if It sounds as if I am back-feeding the radiators on the 2nd floor?

I have attached a sketch. On the left is how I thought it was being done. But perhaps they connected a couple of the radiators on the returns from the 2nd like is shown on the right of the sketch?
 
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Old 07-15-18, 06:45 PM
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To properly zone each floor with zone valves you must have each floor on its own supply and return. All rads for 2nd floor must be connected to the main supply for that floor and return into the main return for that floor before the zone valve which you said is on the return.

For example you have 1pipe going to the 2nd floor and 1 pipe coming back to the boiler and all the rads have to be connected between those 2 pipes so when the stat calls for heat and the zone valve opens water only flows to the rads between those 2 points.

You said you have 5 pipes supplying the 2 floors. Are those 5 including the returns coming back. Typically you would have 4. 2 sup., and 2 returns. What is that 5th pipe for and where does it go.

Check your 2nd floor rads to see if they are heating front to back or going up through the return side. This will tell you if your back feeding.

If you have 2nd floor rads tied into your 3rd floor supply you could possibly be getting heat to those rads by conduction. When the 3rd floor stat calls and the ZV opens those 2nd floor rads are also in the path of that flowing hot water. Although the water might not be circulating because they are tied into the 2nd floor return the water will still heat by conduction if close enough to the main and the zone runs long enough.
 

Last edited by spott; 07-15-18 at 07:24 PM.
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Old 07-15-18, 08:28 PM
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Sorry, I meant 5 supplies that run through vertical chases. There are more returns since the returns for the 2nd floor are separate from the returns to the third floor.

The house was built with one zone. All the supplies would go up vertically and come down in the same chase. What I did was add a separate return for every radiator on the 2nd floor, connect them together, and put a thermostatically controlled valve there. I did the same thing for the third floor.

So theoretically since there is no way for the water to flow through the radiator, it will not be heating. But hot water could conduct from either side. I imagine I have a piping mistake. I am going to turn on the 3rd floor and see if I can tell which way the water is coming into the radiators on the second floor. I assume if it is coming through the radiator valve, it is a plumbing error. If it is coming in the "out" side, perhaps I need a check valve?
 
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Old 07-25-18, 02:02 PM
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OK, I think I am in trouble. Basically the problem is that I have the supplies to the 2nd and 3rd floors connected (in 5 vertical stacks) and the returns separated.

I shut off the valves to the 2nd floor returns and cranked up the heat to the 3rd floor. Eventually the 2nd floor started getting hot. So basically, I have no zoning. So what are my choices? Do I have to run new independent supply lines to each 2nd floor radiator? Could I wire up each 2nd floor radiator (at the radiator) with a valve? I know I could use those thermostatic valves on the second floor but that would mess with the thermostat, and would only be effective if the 3rd floor was calling for heat. OH man, this is a mess. I will certainly do what I can not to tear open the walls. I have 6 radiators, on the 2nd floor, I assume individual wired valves might be the cheapest and most effective solution.

What do you think? This all sounds like a big hassle, and expensive.

But before I started all this I thought I was reading articles about whether to put the valve on the supply or return? If that is true, and only one is valved, why is my system not working? I don't get it.
 

Last edited by cdrat; 07-25-18 at 02:39 PM.
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Old 07-26-18, 02:23 PM
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c,
You only need 1 zone valve per zone and it can go on either the supply or return.

Your problem was feeding both zones off the same supply line. You must have a separate supply and return for each zone.

If your 2nd floor rads come off your 3rd floor supply individual valves wouldn't make a difference because your 3rd floor stat would have to be calling in order for the water to flow through your 2nb floor rads, and each ZV installed at the rad would need a t-stat to operate it in addition to the 3rd floor stat calling.

Is it possible to post some pics of the piping. Can you install a separate supply to the 2nd floor and feed your 2nd floor rads off of that.

It sounds like you brought all of your 2nd floor rad returns into there own return line. You must duplicate that with the supply to the rads. Whatever pipe or pipes are feeding those rads off the 3rd floor main must be taken off and put on a separate supply.

Without pics It's hard to tell exactly what you have done and how to fix it.
 
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Old 07-26-18, 06:26 PM
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OK, I hope this helps. The water to the third floor cannot go through the radiators on the 2nd, but they do share a supply.
 
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Old 07-26-18, 09:13 PM
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I'm looking at the two 2nd floor rads on the left with the aqua return lines. Do they go into a return separately or are they looped together as it looks in the diagram.

Am I correct in seeing 3 supply lines and 2 returns.

Where are your ZV's and pump located precisely.

If those aqua returns on the left loop from one to another that is how they are getting heat when the 3rd floor calls. If you follow the supplies in and the aqua out you can see where it would just circulate from one and feed back to the other.

Those valve symbols. Are they ZV's or shutoffs. The way your supplies are feeding the rads they are going to the 2nd floor every time they go to the 3rd. Even though the water isn't circulating it would still the rads by conduction. They wouldn't get as hot as the3rd floor but they would get warm depending how long the 3rd floor stat was calling.

Would love to see pics of the boiler and piping if possible.

You only need 1 supply and 1 return per zone and all rads for that zone must be in between the supply and the return before the zone valve and pump, if the pump is on the return. If the pump is on the supply it must be mounted before the main line breaks into the 3 zone feeds.

Am I correct in assuming that the red lines are supplies and the blue and aqua are returns.
 
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Old 07-26-18, 10:36 PM
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I'm looking at the two 2nd floor rads on the left with the aqua return lines. Do they go into a return separately or are they looped together as it looks in the diagram.

This is only a diagram, there are actually 5 "risers" in total. The returns go into the line with "T" fittings, not like I drew it, there are no loops that are obvious. Basically all the returns come together, there is a valve and they go into the boiler. There is also a first floor that is newly plumbed and does not have a problem.

Am I correct in seeing 3 supply lines and 2 returns. There are many supply lines that branch out, the returns, by floor, are run together by floor to go into the valves.

Where are your ZV's and pump located precisely. Unfortunately, I am away from the building. The returns come together and after each valve they go into the single pump. I have a picture attached, I will look for more in case it will clarify.

If those aqua returns on the left loop from one to another that is how they are getting heat when the 3rd floor calls. If you follow the supplies in and the aqua out you can see where it would just circulate from one and feed back to the other. Those returns from the 2nd floor go all the way to the basement, and if the valve is closed, where is the loop? I have ball valves on either side of the Honeywell zone valves and I shut them off.

Those valve symbols. Are they ZV's or shutoffs. The way your supplies are feeding the rads they are going to the 2nd floor every time they go to the 3rd. Even though the water isn't circulating it would still the rads by conduction. They wouldn't get as hot as the3rd floor but they would get warm depending how long the 3rd floor stat was calling. The symbols are the honeywell zone valves V8043F1036. I am sure there is some conduction, but a couple of these 2nd floor radiators are getting really hot, and they are not right on the vertical as illustrated, is there a way I can tell if it is circulating? The system still is going to be pressurized, I guess, so the bleeder doesn't help.

Would love to see pics of the boiler and piping if possible. I have attached the only picture I could find. Obviously a very old system heavily modified, you can see the old pipes, put in when there was no pump. I thought that would be the problem ; the 3" pipes.

You only need 1 supply and 1 return per zone and all rads for that zone must be in between the supply and the return before the zone valve and pump, if the pump is on the return. If the pump is on the supply it must be mounted before the main line breaks into the 3 zone feeds. I have at least 5 vertical stacks, more than as shown in the diagram. I connect all the returns from the 2nd together before the valve and all the returns from the 3rd together before the valve, obviously the supplies are all connected in each riser. So might I be able to solve this with check valves?

Am I correct in assuming that the red lines are supplies and the blue and aqua are returns. Yes
 
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Old 07-27-18, 12:16 PM
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c,
If all your returns from the 2nd floor come back to one common pipe and are connected before the zone valve which is proper and the same with the 3rd floor then it would seem your problem lies in your supply line distribution.

You can not have any interconnection between the two zones. Your supply's to the respective zones must be separated.

If you were getting back feeding through a return line from 1 or 2 of the rads a check valve would help but with your returns separated and 2nd floor closed it sounds like your getting conduction through the supply. Where were you thinking of placing the check valves.

Every time the 3rd floor stat calls and the pump comes on it will open the check valve.

From what I can see the only option is to separate the supply's to the zones. Duplicate what you did on the 1st floor.
 
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Old 07-27-18, 08:06 PM
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The difference between the 3 floors is that the first floor separates from the supply in the basement (and has smaller copper tubes), and the 2nd and 3rd separate on the 2nd floor (and the supplies are 2"). There are no circuits for ghost circulating, but this used to be a gravity system, I think your theory of conduction is the only one that makes sense. So what if I put a spring check valve at each 2nd floor radiator? That would limit the surface area for conduction and since the pipes are so large, would stop any convection that is going on. I would think the 2" "T" that the 2nd floor branches out from the vertical pipe going to the 3rd floor would generate some sort of convection as well. And when the valve on the returns for the 2nd call for heat, it flows right past the check valve, otherwise it is limited.

My 2nd idea is a little crazy. What if I reversed the supply and returns to the 2nd and 3rd floor so that the valves were on the supply? So in my diagram all the reds were blue and all the blues, red. Any conduction or convection would happen on the cooler returns. Have no idea if that would be enough, but it sure would be a cheaper solution than installing 6 check valves in 100 year old pipes. One strange thing is that the valves on the radiators would be on the return side, does not sound good.

What do you think? Either of these ideas have merit? I just want to avoid opening up these walls if there is any reasonable way.
 

Last edited by cdrat; 07-27-18 at 09:23 PM.
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Old 07-28-18, 10:53 AM
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By changing your ZV's from the return to the supply side, unless you can install it where the 2" tee branches off to the 2nd floor before the rads I can't see where it would do any good.

Your check valve idea may have merit depending how the heat is getting to the rads. I have used them in the past on jobs to stop the water from back feeding to rads.

Have you determined yet which direction the rads heat from. Are the returns getting warm first or are they heating from the supply side.

I would try one first to see if it makes a difference. Make sure after you install it that it opens when the 2nd floor stat calls for heat. The pressure from the pump is what opens these and when the 3rd floor stat calls and the pump comes on what's to keep this closed. Maybe with the ZV closed also it may be enough. Everything is just a guess without being there to see the piping layout.

The size of the pipes in your case doesn't make a difference. It's the way the pipes are installed. As I said, when zoning, each zone must have its own supply and return operating independent of each other.
 

Last edited by spott; 07-28-18 at 11:10 AM.
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Old 07-29-18, 09:35 AM
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Ok, thanks, that it what I will do. I will check and see if the supplies or the returns are getting hot first. If it is the returns, I do not know what I will do. I understand your point about the pressure, If both the 3rd and 2nd call for heat at the same time perhaps the water will just flow to the 3rd instead of pushing through the check valve on the 2nd. It will take me a couple weeks before I can test this, I will be back.
 
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Old 07-29-18, 10:10 AM
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I canít follow all the stuff here, and maybe this has already been established, but I think I see how some of the second floor radiators would get heat when only the 3rd floor is calling for heat.
 
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Old 07-29-18, 08:21 PM
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That is very good, thanks. As I remember, I was feeling pipes in the basement from the 2nd floor that were warm, and I think they were returns. I did not think about it at the time, but your diagram makes sense. If this is it, there should be a fairly easy fix; check valves on all the 2nd floor return lines before they intersect another pipe. All of the returns from the 2nd floor are brand new and independently go to the boiler room before they connect with all the rest of the returns. So that means I may be able to put all of the check valves in new pipes in the basement. That would be great.
 
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Old 07-30-18, 05:17 PM
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Hope that works. That would be great solution.
 
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Old 09-16-18, 09:57 AM
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OK, I went to the building and figured out I will need 3-1" check valves and 1-3/4" check valves. Apparently I have two sets of radiators that share returns. I am all set to install them. But, I am not sure which ones to get. My inclination is to install swing check valves like these. https://www.supplyhouse.com/Bluefin-...alve-Lead-Free

Made by bluefin. I was thinking these as opposed to a spring because I thought they would be more reliable. I have new copper pipe so solder-in makes sense. I don't mind paying a little more for dead-on reliability if that is available.

The prices on check valves are all over the place ($8 to $150 and much more) . I see some (taco) that I assumed would be higher quality (approx $50), but they say maximum psi of 125, I have to do more research, this doesn't make total sense for me.

Does anybody have check valves that are super reliable? But then do I have to pay to get that?
 

Last edited by cdrat; 09-16-18 at 10:34 AM.
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Old 09-16-18, 11:29 AM
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cd,
Where do you plan on installing these checks. Supply or return lines.

My guess is the big price difference in the Taco's is because you are looking at Flochecks and not regular swing checks which are different.

The FC can be opened manually if need be where the swing or spring check cannot.

Spring checks can be mounted vertically and springs must be installed horizontally only.

I have read literature that says a swing will give you full flow, where a spring will not because of the design. The swing opens the gate on flow where as the spring opens and water must go around it if you can picture it. That's according to some literature I read somewhere.

They basically all do the same thing. I think if it were me I would consider the flochecks that can be opened manually in case of a problem.

You mentioned the rating of 125PSI. What is your concern. Your system operates at under 30PSI so that should be of no concern.

Hope this helps a little.
 

Last edited by spott; 09-16-18 at 11:50 AM.
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Old 09-16-18, 12:24 PM
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These check valves would only be on the returns to the 2nd floor. I read of a number of problems with the bluefins which gives me pause, I would assume I can trust the Taco, although I cannot see where I would want the return lines to be forced open. I can mount everything horizontally with no problem and certainly do not want to restrict the flow, so I will stick with the swing valve. I was thinking of the Boiler pressure, thanks for clearing that up.
 
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Old 09-16-18, 01:43 PM
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I don't have any experience with the Blufin CV. The only ones I've ever used have been threaded.

Can't find any sweat other than Flocheck valves. I usually use Watts which has served me well.

If you go with another brand other than the Blufin you may need M X C adaptors if you are going to solder, so be sure you have enough room.

One other thing to consider is bleeding. If you are bleeding each individual rad shouldn't be a problem but if bleeding from the boiler, remember that it takes the pressure of a pump to open the check valve, Water will not flow by gravity as is needed for bleeding a loop system. A flocheck valve can be opened manually for that purpose and then closed for proper operation after.

Just a thought. Don't know if it's relevant in your case.
 
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