Controlling Zone Circulator on Radiant Loops that also have zone valves?

ColdTurkey

This is my parents house, it's always cold, not in small part because they installed a new boiler but the extra circulating pump was never connected to it, so I'm trying to help with pre-existing problems. I just had a ZVC406 installed for other reasons, there are 6 zones in all including indirect hotwater. So far it's working well except this one area.

This is my system diagrammed, or at least the part I'm interested in.

https://ibb.co/rs0mXG3

For some reason, the radiant floor loops heating a big kitchen/dining room downstairs and the master bath upstairs has both a single circulator and zone valves. Both zones share the circulator. Each zone has it's own thermostat, which is goes to the ZVC406 panel and the panel opens the valves.

How can I control the circulator to turn on when either thermostat goes off? I have no problem buying a circulating relay for this, but I'm wondering about the thermostat wiring specifically.

Ironman

Why would you want to turn the circulator on when the stat is off? If the stat is not calling, the ZVs would be closed and you could have no circulation.

hot_rod

Is it a multi temperature system, maybe fin tube and radiant mix?

A piping drawing or pic would help

Gman66

Ironman said:

Why would you want to turn the circulator on when the stat is off? If the stat is not calling, the ZVs would be closed and you could have no circulation.

Bob, I suspect that when the OP says "thermostat goes off" he means "calls for heat".

OP: the end switches on the zone valves should drive the relay for the circulator. If you really want the bathroom to be able to run independently you would wire the end switches in parallel such that either zone triggers the circ relay. However, that may cause short cycle from the bathroom micro zone. Alternative would be to not wire the bathroom end switch and thus the bathroom would only get heat when the downstairs larger zone is calling for heat; this can work if the downstairs zone is almost always on.

HomerJSmith

"How can I control the circulator to turn on when either thermostat goes off? I have no problem buying a circulating relay for this, but I'm wondering about the thermostat wiring specifically."

I'm confused. I'm not that smart. I'm the only person that I know that flunked Kindergarten and had to do it twice. Your diagram doesn't make sense to me. It's incomplete. However, summarizing...

1) You have a mixed temperature sys, baseboard and radiant floor?
2) The radiant zones are the kitchen-dining rms and the master bath upstairs.
3) You have one pump that pumps to the radiant zones, only.
4) The flow thru the radiant zones is from the pump thru Taco 571 zone valves.
5) There is no or insufficient heat in the kitchen and mast bath?

"How can I control the circulator to turn on when either thermostat goes off?"------Please, clarify that statement. What is your purpose in doing that? What are you trying to achieve?

A picture is worth a thousand words.

That diagram is replete with piping errors. In order to have heat in a room, you must have flow of heated water to that room and a heat emitter, whether baseboard or pex tubes. "Flow is the conveyor belt that moves heat energy from the boiler to the heat emitter." Are you sure that the zone valves are actually opening and the pump is actually pumping? Feel the pipes. How do you balance the flow between the two radiant zone? The shorter zone will get the greatest flow, starving the longer zone for flow.

The flow and the temperature in baseboards are different than the flow and temperature of radiant infloor. How do you control that?

I don't know whether you sys has a boiler pump and a radiant pump or a single pump trying to do the whole job.

ColdTurkey, you need to be more specific.

rick in Alaska

On the zvc406 control, there is a set of contacts on the bottom that say pump end switch. On one leg of that switch, put a hot 120 volt wire. On the other leg, take that to the hot wire on your pump. Then run a neutral wire to your pump and you are done.
Now, if either one of your zone valves calls for heat, it will turn the pump on.
Rick

ColdTurkey

Ironman said:

Why would you want to turn the circulator on when the stat is off? If the stat is not calling, the ZVs would be closed and you could have no circulation.

The reverse, I want the circulators off when the valves are close. When the thermostats aren't calling for heat.

Sorry for my bad terminology.

hot_rod said:

Is it a multi temperature system, maybe fin tube and radiant mix?

A piping drawing or pic would help

The rest of the house are simple zone valves and thermostats going to old-fashioned cast iron radiators.

The size of the place is you can think of that section as nighttime and the section I have trouble with as daytime/office. Those are all radiant loop in the floor.

ColdTurkey

Some people asked for a better diagram or picture, here:

https://ibb.co/F801sZ2

I'd just like to be able to get the zone circulator working in sync with either the kitchen thermostat or preferably both thermostats, if possible. Right now it's completely manual (on/off switch) and I'm thinking it could be wrecking the TACO heads (we went through a lot of those).

Ironman

Do you have a mixing device for the radiant floor? You don't want to send the same water temp to the floor as what's going to the radiators.

rick in Alaska said:

On the zvc406 control, there is a set of contacts on the bottom that say pump end switch. On one leg of that switch, put a hot 120 volt wire. On the other leg, take that to the hot wire on your pump. Then run a neutral wire to your pump and you are done.
Now, if either one of your zone valves calls for heat, it will turn the pump on.
Rick

Rick, I don't think this will work because it appears he has a separate circ for the radiant. If one of the other zones calls in this scenario, the ZVC will turn on the radiant circulator.

As Gmann66 said, you need the end switches of the radiant to go to an SR503 pump relay's thermostat terminals and let that control the pump. You would jump the pump's hot wire to zone 1 & 2 "H" terminals.

rick in Alaska

Yeah. Didn't see the rest of the piping, and it looks like it is not all there anyway. I would like to see all of it.
Rick

HomerJSmith

Ok, ColdTurkey, I get it. The second diagram is much better.

So, when the radiant zone valves are off, you want the radiant
pump to turn off and you would want to do that with the ZVC-406. Well, you can't do it without an added part, if what I state below is true.

So, you have 3 pumps: a central boiler circulator, a radiant circulator, and an indirect W/H circulator.

I'll put together a wiring diagram for you with the added part list.

Basically, you need a Fan Control, a 4X4 metal electrical square box, a grounded cord and plug and 18/2 thermostat wire to the zone valves and a flexible conduit to the pump from the Fan Control. Notice the pump and the Fan Control in the picture below.


You need to figure out the flow with a balancing valves on both radiant circuits.

So, what part of the house is cold and why is it cold? What is the model # of your radiant pump?

hot_rod

I don't see a circ for the indirect?

If there is on on the tank, isn't the boiler and indirect circ in series?

How many total t-stats? two radiant and one high temp zone? 3 circs?

HomerJSmith

I'm still looking at putting a drawing together.

The best way to achieve the radiant pump to turn off when the radiant circuits aren't calling for heat is to switch out the fixed speed radiant pump for an ECM pump like an Grundfos Alpha and install a Caleffi Quicksetter balancing valve on each radiant circuit return. The Quicksetter would regulate the flow thru the radiant circuits and when the 571 zone valve closes and one is still open the pump ratchets down and when both zone valve close the pump ratchets down to nothing. You just plug the pump into any electrical receptical and set it to auto and forget it.

If I was to do that, I would add some Webstone valves so that I could push water thru the radiant circuits to eliminate any air pockets that might inhibit flow.

hot_rod

HomerJSmith said:

I'm still looking at putting a drawing together.

The best way to achieve the radiant pump to turn off when the radiant circuits aren't calling for heat is to switch out the fixed speed radiant pump for an ECM pump like an Grundfos Alpha and install a Caleffi Quicksetter balancing valve on each radiant circuit return. The Quicksetter would regulate the flow thru the radiant circuits and when the 571 zone valve closes and one is still open the pump ratchets down and when both zone valve close the pump ratchets down to nothing. You just plug the pump into any electrical receptical and set it to auto and forget it.

If I was to do that, I would add some Webstone valves so that I could push water thru the radiant circuits to eliminate any air pockets that might inhibit flow.

I think the Caleffi ZCV can do this in one box, once I'm clear on 3 pumps, 2 zone valves, how many t-stats.

The caleffi box allows you to configure the 3 pump outputs, it has some flexibility.

Does the boiler circ operate from the boiler output? Could it?

Any heat call turns on the boiler and it's circ, the others run from the relay box.

HomerJSmith

I asked how many pumps in the sys, in an earlier post and assumed that there were three. I never got an answer. ANSWERING questions helps make a proper diagnosis.

The (Taco ZVC 406 and secondary pump) can handle 3 pumps, a boiler, DHW, and secondary pump. The problem is that the secondary pump turns on when any thermostat calls for heat and any zone valve opens. ColdTurkey, wants the radiant pump to operate only when the radiant circuits calls for heat, and not when any baseboard thermostat calls for heat as is now happening.

It would be so much easier if he had a Caleffi Z One or Honeywell ZV with a separate end switch and not the three connections that the Taco 571 ZV has on the radiant circuits. Connections 1 & 2 operate the heat motor and connections 2 & 3 operate the end switch, which, it would seem, to require 2 transformers. I was concerned about transformer polarity.

I think I have it figured out, I'll see.

I would still use Quick Setter balancing valves.

ColdTurkey

Hello, sorry, I'll answer as often as I can. I'm not trying to ignore anybody's questions.

There are 2 pumps in the system. The indirect water heater has no pump of it's own. There's only the central and zone circulator. I didn't set any of this previous system up. I think the companies my parents hired had more experience with ducted heat than hydronics 10-20 years ago -- which was more typical for the area.

To answer some questions why the house is always cold, it's an old stone house with 20" walls with no insulation so it's prone to be cold. Basically it comes down to the circulators not being in sync. They put in a second boiler that since died (an NG condensing boiler) and the company wired all thermostats directly into that (which is why I moved it to a central box) except the NG boiler people didn't sync that boiler with the zone zirculator or even add it to NG boiler. It was still on the unpowered RJ845a screwed onto the oil boiler. With either boiler, things were not warm.

My parents either manual overrode the kitchen/bath taco zones and put on the circulators, which heated the kitchen/upstairs bath well enough, but stole heat from the rest of the house when it was perpetually on, or they put the taco valves on auto and turned off the circulator since they thought it might kill it pushing hours long against a closed valve. Not enough water moved through the radiant floor loops when open with just the central circulator and ended up cold.

The Honeywell RJ845a driving the zone circulator on the oil boiler has since died sometime, I have verified with a voltometer and trying the override and moved the circulators on a temporary switch. I think it was wired to do so perpetually, there was no thermostat wire attached anywhere.

The second diagram doesn't include all this about the second boiler because it's rather involved and extraneous info afaik but as far as piping is concerned as well as the valves, it is complete. All the valves to it are shut off in any case.

I do have a question with IronMan's idea.

https://forum.heatinghelp.com/discussion/comment/1589515/#Comment_1589515

I do have access to a Taco SR relay so I can wire it like that. However, the 2 wire thermostats go to the ZVC-406. The ZVC-406 sends a 3-wire wire hooked all terminals of the gold taco valves (old style). I guess so it can show the "Valve Open" status light.

Is it as simple as bringing another 2-wire to those valves and hooking it up to a taco SR-50x? I casually do house wiring no problem, but I'm afraid of frying something on these expensive boards and the SR sending a bad signal to the SVC.

Would it be easier to disconnect the 3rd wire from the SVC to the valve and then just wire the SR as shown to the valve? I'm not particularly concerned about a valve open status light showing up or not.

Thank you for all the help so far!

hot_rod

you mentioned an indirect, is it via a zone valve? On priority?

ColdTurkey

The 4 other zones are indirect water heater and 3 going to different rooms with big old iron radiators like this. There is no baseboard. The indirect water heater is on priority zone 6 as advised by a professional.

Each zone has its own thermostat. 5 in the house, waterheater has a limiter of some sort set to 120f. Boiler has a honeywell aquastat and is wired to a dead RJ845a.

Since the ZVC switchover, these other zones have had no problems whatsoever.

ColdTurkey

hot_rod said:

you mentioned an indirect, is it via a zone valve? On priority?

Yes, on zone valve and on priority zone 6 and wired to a temp limiter at 120f iirc. It's not often called for heat at all.

They've had no issues with hot water before or after this change, they only take showers so they don't use much anywhere else including sinks. Any guests never complained.

hot_rod

So on an indirect call the three heating zones also flow? Just the radiant zones are locked out on priority? Or do the 3 heat zones have zone valves?

ColdTurkey

All but the indirect water heater are locked out when the IWH calls. But priority mode can be turned off with a flick of a switch and then the IWH is just like any other zone.

Graph 3 to clear anything else up:

https://ibb.co/ZxM1Jc0

Although I don't promise every single pipe is there, that's the basic jist of the system.

Brown wire is 2 strand. Yellow wire is three strand.

HomerJSmith

Ok, I get it and I have a solution which I will diagram for you in the next day or so. I am busy. You can use the Taco 406 and a set up like the photo I put on my post and it would put the radiant pump working only when one or both radiant zones are operating and the pump would be off otherwise. The DWH should be on priority setting in the Taco 406 if you use a lot of hot water, your preference.

The way the Taco 406 works is that there are 2 transformers on the board. The A transformer powers zones 1 thru 3 and transformer B powers zones 4 thru 6.

The radiant thermostats for the kitchen and bath must be on the same transformer, such as 1 thru 3 or 4 & 5 zone positions. That's important. If one is on 1 thru 3 and the other is on 4 - 5, change one of them so that they are on the same side (transformer).

The Taco 571 zone valve has 3 terminals. Screw 1 & 2, when 24V are applied operates the heat motor which opens the valve to let water flow thru it. Screw 2 & 3 are the end switch which turns on the boiler thru the Taco 406.

The radiant pump can not be operated thru the Taco 406 because any zone calling for heat will turn it on and you only want the radiant zone thermostats turning the pump on. However, you need the end switch connection in the Taco 406 to turn the boiler on. So, basically, there has to be a wiring change between the 571 and the 406, which I will diagram for you plus added parts that aren't too expensive.

To be continued...

ColdTurkey

Ok, wow thanks. They're already on zones 4 and 5.

I was about to change to a grundfos alpha as it sounds much easier all the way around, but I wasn't eager to get into learning how to bleed the system at the moment. Probably a summer project if it become necessary, tbh.

To answer a previous question about the circulator, it's a Taco 007-F5. It's on 1" pipe. Like so:

https://ibb.co/R30FD7S
https://ibb.co/XxFNkwj

HomerJSmith

ColdTurkey, before I draw this up for you, I need to know about the ZVC 406. There is an older version and a newer version. The newer version, if you open the case, has a C connection where the thermostats connects to the board. It would be R W C terminal. The older model have only a R W terminal thermostat connection. Which is yours? This is important to know, otherwise I have to make two drawings.

The Alpha pump is probably a little overkill and the only reason I suggested it was that it would eliminate the end switch problem with the ZVC 406. I would stay with the 007 even tho it is a lot of pump for your 2 radiant zones. I would put my money into Caleffi Quick Setter balancing valves.

ColdTurkey

Hi Homer,

Yes, it looks like the new type, all the Thermostats coming in have the option for Carrier wire.

https://ibb.co/6rg12Sx

(My heater guy switched the colors on one thermostat on purpose, Idk why but I left it and seems to work.)

>I would put my money into Caleffi Quick Setter balancing valves.

Something I'd do in the summer, heh. Will the heating be slower but more balanced as a benefit or will it possibly balance the rest of the system better by drawin less water?

hot_rod

An Alpha or any ∆P circ would both save electricity and adjust to the one or two zone call, keep it on the upgrade list.

Unless I'm missing something you have 6 zone and zone valves, 5 thermostat and the indirect control stat?

Indirect on priority. I tried to wire up a Caleffi ZCV box and it appears to do all you ask. It has 3 pump outputs, zone 1 can be toggled to priority, one set of the three available end switches is just connected to zone one.

The pins below can adjust how the pumps power up, all three at once, only one on an indirect with dedicated pump, also the aux end switch can be configured with the dip switches above.

I'd be glad to send you a sample 3 zone Homer, to play around with the multiple control options it offers.

The 6 zone included 2- 40 VA transformers in parallel, for 80 Va across all valve connections. The 3 and 4 zone has one 40Va, but you can add another for 80Va if you are driving a lot of high draw zone valves.

https://www.caleffi.com/sites/default/files/caleffi/uploads/files/wiringguide-zsr-zsr101-zvr.pdf

HomerJSmith

I'm trying to do this on the cheap. Caleffi is the darn best company out there. Caleffi are innovators not imitators and I am grateful for their contribution to the hydronic industry.

Thank you for your offer. I down loaded the pdf and will review it. When I was young I had all the time in the world. As the scythe of age cut, I find that time has become short and there is never enough of it. My plate is full of projects that demand my attention that get shifted to the next day. Curse-ed time. If I had only known, I would never have squandered it so recklessly.

I will review it.

ColdTurkey

Does it seem impossible to do with the Taco ZCV?

Should I just get the Caleffi one?

Ironman

As hotrod suggested, if you'd simply install a delta P circulator like the Grundfos Alpha, you wouldn't have to deal with all this wiring and controls. It's a smart pump and all you have to do is plug it in and set it to the delta P mode. it will do the rest.

HomerJSmith

Here is the drawing of how to wire up your sys so that the radiant pump operates only when the radiant thermostats call for heat.

Alpha pumps are expensive and that would work because the Alpha runs all the time, but ramps down when the 571's are closed.

Per my drawing:
The Fan Control Center should be plugged in to the outlet that the Taco 406-4 is plugged into. The Fan Control Center is powered by a cord and 3 conductor plug. #14 wire cord is recommended

You need to disconnect the #3 thermostat wire from the 571 and the Taco 406, which disconnects the end switch to the 406.

The #2 & #3 connections to the 571 is with #18 ga thermostat wire. The connections from the Fan Control Center Relay pole 2 to the end switch on the Taco 406-4 is with #18 ga thermostat wire. Relay pole 2 turns the boiler on.

Fan Control Center Relay pole 1 is wired with #14 thhn stranded wire, Black-White-Green, protected in 3/8 flexible metal conduit from the Fan Control Center 4X4 metal box and the radiant pump. See my picture posted earlier.

I pull pole 1 & pole 2 Normally Closed (N/C) wires from the socket on the relay as you don't need them. You make all your connections to the Normally Open (N/O) wires.

Take Pole 2 wires (two of them) outside the 4X4 box to make the connection to the 18 ga thermostat wire to the boiler end switch connection.

Follow the wiring diagram.



https://www.supplyhouse.com/Packard-FC90112-Fan-Centers-DPDT-Relay-120-VAC-Primary-24-VAC-Secondary

hot_rod

Shop for a ∆P circulator, they will run your system much better, maintaining the required flow as ZVs open and close. They save 50% or more electricity over the standard 80W circ, eventually paying for itself. Plus the extra transformer you would be adding in the fan center will add additional power draw.

Shop around, electronic circs are not all that expensive, bring your system into the 2020s.

HomerJSmith

ColdTurkey, if you decide to go with an ECM pump, you have to break into the boiler sys to switch it out. At that time I would add two Caleffi Quicksetter balancing valves on the return of each radiant zone. I am a big believer in using balancing valves to regulate flow in uneven lengths of multiple circuits.

You're still have to force water thru the radiant circuits to get the air out after you change out the pumps. A circulator will not pump water thru an air space in a circuit.

You might want to think about something like this on the supply and return that you can hook up a garden hose to and use street pressure to force the water thru the radiant sys.

https://www.supplyhouse.com/Webstone-50613-3-4-SWT-Webstone-PRO-PAL-Ball-Valve-w-Drain

rick in Alaska

I would use an RIB relay instead of a fan center. It is much smaller, and the relay is not noisy like the fan center is. I believe it is also much cheaper.
Rick

HomerJSmith

rick, I use RBI relays all the time. You still need a transformer to operate it.

rick in Alaska

HomerJSmith said:

rick, I use RBI relays all the time. You still need a transformer to operate it.

You can use a transformer or just 120 volts.
Rick

HomerJSmith

rick, I am interested in how you would wire it up. A quick sketch would be nice.

I can see a RBI 24V relay wired to the "b" side transformer of the Taco 406-4, but I am concerned about overloading that transformer.

That "b" side transformer would power at max draw, 3 Taco 571 zone valves, unless the DHW is set on priority in which case it would be two Taco 571's, the Taco 406-4 relay and the RBI relay. It would also power any "Nest" type thermostat in the future. I'm not sure how that all would work out.

rick in Alaska

You just wire it the same way you did the fan center. It is basically the same thing, except it does not use the transformer. The relay inside can be powered by 24 volts or 120 volts.
Rick
Edit.I was looking at it a little wrong. You can still either feed the RIB with 120 or 24 by taking the power off the Taco. Then use the Taco 24 volt transformer for your end switch circuit. You would still be using the same amount of power off the transformers as if you had the zone valve wired in direct.
I will see if I can figure out a way to draw it up and post it.
Rick

HomerJSmith

Rick, I can see where you are going with this, use the Taco 406 "pump end switch" or the "zone & pump end switch" connections to power the RBI relay. Close but no cigar.

The RBI relay would turn on when any zone calls for heat except when the DHW zone in priority mode and calls for heat (see the small print). This would defeat the purpose of ColdTurkey's post. He would be in the same boat he's in now.

rick in Alaska

Have the radiant zone valves end switches power the RIB by using the 24 volts from the ZVC ( forget the 120 volts I was talking about earlier; Wrong thought on my part). Take the ZVC common to the Taco zone valve as it is wired now, on pin 2 of the zone valve. Then take the ZVC R wire to the RIB input line. Take the other wire of the RIB to terminal 3 of the Taco zone valve. Then on the output of the RIB, run one hot 120 volt line to one side of the RIB, and take the other RIB line to the radiant pump. Run a neutral and a ground to the pump and you are done.
When the radiant has a call for heat, the thermostat sends a signal to the Taco ZVC, which powers open the zone valve, turns on the boiler and circ pump, opens the RIB, and powers the radiant pump. Pins 3 and four on the Taco ZVC must have a jumper wire installed also.
Rick

HomerJSmith

I'm a little confused which is common for me. Rick, a diagram would be nice. You may be onto something.

The cost between your suggestion is about the same as my hookup. I do know that my suggestion will work.

hot_rod

I think this is Ricks solution. The RIB is a nice clean installation, all wiring could be inside the relay box and it has the 1/2" mount post. Clean, quiet, safe.

Although the Caleffi relay box could do this without and additional RIB. Probably 20 bucks for a RIB and some wiring changes.