Request for help understanding Taco Zone Valve Control with Buderus R2107

pej2000

Hello Friends. I'm starting a new post while waiting for my replacement R2107 which is delayed.

I noticed today that the Zone 1 lights are not coming on despite demand, which is a new issue. So I'm trying to understand the connections.

Zones 2 and 3 are pretty clear: thermostat wires come into the Taco board on top and valve signals go out on the bottom.

Zone 1 is connected to a manifold at the back of the house serving 4 different rooms each with its own thermastat. It looks to me like all the thermostats are probably connected in parallel with one connection on the top of the Taco board at Zone 1.

What I don't understand is which there is no valve connection on the bottom of Zone 1? The Valve connectors 3,4 are jumpered together and there is no output. What is the value of sending a thermostat signal indicating demand into the board with no feedback to a valve or to the R2107?

On the question of the Zone 1 lights I did measure some voltages to try and understand the operation. I'm seeing the Thermostat terminal at each zone measures ~24v when there is no demand and 0v when demand comes on.

Thanks for any suggestions. Much appreciated.

HomerJSmith

Thermostat terminal at each zone measures ~24v when there is no demand and 0v when demand comes on.

That is perfectly normal. I guess you are measuring the voltage at the TT thermostat connection. When measuring voltage when the thermostat isn't calling for heat, The voltage on the red T wire is 24Vac to the transformer Common. The white T wire is the transformer Common thru the zone valve's motor windings or in the case of Taco Sentry ZV charging circuit.

With the thermostat calling for heat and when you measure the thermostat TT connection from the red wire to the white wire you will get 0Vac because there isn't any difference in potential. It is the same as touching both probes together. 0Vac

A jumper between #3 & #4 on zone 1 is needed to turn on the Boiler TT connection. It is used when the ZV doesn't have an End Switch.

hot_rod

Zone 1 has 4 different room thermostats connected?

pej2000

The Buderus R2107 does have the FM241 board controlling a mixing station. The mixing station has a pump. I valves for Zones2 & 3 but not one for Zone 1, so I assume there is pressure whenever the mixing station pump is on.

The R2107 sends 120v to the Taco Board, and receives 24v back to the FM 241. Besides the Zone2 and 3 valves, I don't see any other signal coming out of the Taco board.

Yes there are 4 rooms with thermostats connected to the manifold which is controlled through Taco zone 1. I'm just assuming all 4 thermostats are connected together to get the signal to zone 1.

pej2000

Maybe what I'm saying doesn't make sense. The thermostats must be connected to the manifold actuators. I don't know what signal is coming into Taco zone 1. I do know that the zone 1 light usually goes on when a manifold thermostat is calling for heat. That light seems to be out now (maybe because of the R2107 issues, replacement on its way).

Brent H.

If there are 4 thermostats at the back of the house I bet there is a remote zone manifold back there as well with 4 zone valves. My bet is that the wire from Zone 1 of your Taco panel runs to the remote zone panel and is wired to activate when any of the remote zone valves is activated.

pej2000

OK. I tried to take a better look at the manifold panel.

I don't see a panel in there.
I do see 6 brown wires and a power cable coming in from the top and 6 actuators, which further confuses me because I still only have 4 thermostats back there. 4 of the actuators are labeled to match the thermostats and two are blank, but I've seen them open. The wiring is messy as you can see in the picture. I don't see a cable that I could claim was exiting to the Taco zone 1 valve control
.

Rich_49

Time to update and upgrade . What a mess . Get yourself some manifold adaptors , new actuators and however many zone control modules you require . Each manifold locations end switch should run back to Tstat terminals on Taco control and wherever you have an endswitch connected to the T stat terminals jump out 3 & 4 . It looks alot like you are showing a zvc406 EXP cover and wiring diagram but the actual control looks to me not to be an EXP or at least a modern EXP . looks different from the wiring diagram also .


https://www.supplyhouse.com/sh/control/search/~SEARCH_STRING=uponor zone control module

pej2000

Thanks. I'm totally with you on the update/upgrade. I hate seeing that mess.
And you are absolutely right about the board and diagram not matching. I noticed that too.
I just wish I understood the logic of the current hookup: like what are those extra actuators for? And what is the connection to Taco Zone 1. Great mystery, but I'm starting to hate it.
I'll keep studying.

EdTheHeaterMan

The Logic of this system looks pretty simple if you take it a step at a time.
from the manifold with 4 thermostats. Any zone thermostat calls for heat and causes the manifold actuator to open. the end switch from that actuator will close and sent the closed circuit to the TACO ZVC #1 zone thermostat terminals.
This will cause the system that the ZCV is controlling to operate. There is an end switch on the TACO ZVC that has a red line voltage wire connected to it. I believe that must operate something like a system circulator to move the heated water to the different zones.

Zone #2 and #3 on the TACO ZVC are operated by a thermostat from zone 2 (or 3) to operate a zone valve with an end switch. This is normal

Since zone one on the ZVC is not operating a single zone valve with a single end switch, a Jumper is placed between 3 & 4 on the zone valve connection side to act as a closed end switch when ever one of the 4 other thermostats calls for heat (since there is no single zone valve with end switch).



By using the Buderus R2107 the boiler temperature is not controlled or adjusted by any room thermostat. There is no place to connect a thermostat or an end switch from a room thermostat operated device. The only thing that the ZVC end switch operates is what ever device is connected to the red wire in the last picture indicated by the yellow arrow.

pej2000

This is great progress. I missed the red wire at the Taco ZVC (thought it was just part of the power supply. It actually does go to the circulator pump at the mixing station! So if I'm understanding correctly any call for heat to any of the three zones will activate the circulator. Zones 2 &3 have an additional output to open their respective zone valves.




I also didn't understand the box on the left of the manifold panel was an actuator. Although the wiring is very difficult to follow (I'll keep working on it), It is mounted to a regular electrical box with a big yellow cable I assume is 120v power comes into the back. Despite your wonderful diagrams I still don't quite get how this device works. Too me the Red and white wires look like they are coming from manifold actuators tied together.

Each of the 6 manifold actuators has 2 yellow and 2 red wires. The reds seem to be mostly connected together and some of those appear to go to the left actuator. I'm not finding the cable that goes to the Taco Zone 1 thermostat connection, but I'll keep looking tomorrow.

I'm guessing the 2 extra manifold actuators are connected in parallel with one or two of the marked rooms. I should be able to figure that out by sequentially activating 1 thermostat at a time.

HVACNUT

Jump TT at zone 1. If if works, then look for a break or bad splice on the Red and White wires going to the end switches on the Zone valves. 

Brent H.

The box on the end is a 24V AC transformer that is providing power to the actuators.

Here is a diagram of a single zone. Ed’s drawing is basically this times 4.

Rich_49

pej2000

OK! This is Great!
I jumped TT at Zone 1 and the lights came on. Sure enough the red wire had come loose, reattached. That part working again. Excellent. Can't believe how much I'm learning.

Then back to the manifold panel.
Turned off all the thermostats and the 2 extra actuators came on (5&6) so I guess those are returns for when there is no call for heat but the pump running?

The tangled mess of wires now makes sense (and I started labeling them). All of the actuator red wires are combined to the one end switch cable which must go to the Taco Zone 1 valve input. One yellow wire from each all combine to the transformer. The other end of the transformer goes to Rh on all the thermostats. The second yellows individually connect to each Thermostat white. Whew.

I'm just so happy to understand how all this works now.

My plan is to install the new R2107 when it hopefully arrives today (shipping was delayed yesterday). I have all the settings written down.

I'd like to clean up the wiring mess eventually. but I'm also not the neatest person in the world.
Is there a kit, board, organizer type thingy I could get to make me look more professional?

Rich_49

See picture above . You can make that pretty with the control module and a staplegun , be careful

EdTheHeaterMan

@pej2000, It is good to get to understand your system. Time was (back before 1980) there were no zone control panels. A typical 3 zone wiring system would look like this and it was the acceptable way to do things. The problem with this way of doing control wiring was confusing because there is more than one way to accomplish this. And if the previous installer did not do it the way you learned how to do it, then trouble shooting became impossible for some mechanics.

Your 6 actuator system was put together the old school way. there are zone control panels available from Wirsbo to make the wiring easier to follow. the problem you may find is the fact that 2 of the actuators that open when the 4 thermostats are not calling. I don't believe there is an option in the Wirsbo zone control panels to accomplish that. You may be just as well to leave well enough alone in this case. Just file this advice under "If it ain't broke... Don't fix it"

pej2000

Turns out I was wrong about the 2 'extra actuators'. I decided double check everything by going zone by zone. The 2 extra belong to the guest bedroom/hallway and now I've labeled them. There are also two wired together for the master bedroom. Then office and masterbath to make six.

I totally agree with the 'if it's not broke don't fix it' plan. A problem with adding a control panel is just how tight the space is....but it kind of sounds fun...Might check into it after the holidays to avoid creating any additional drama :-)

Many many thanks for all the info. It's truly amazing to be able to get this kind of support/expertise online.

pej2000

Actually I could do a 4 zone since some are hooked together. And the Wirsbo looks pretty small!

pej2000

OK. So the Wirsbo 4 channel is small and would beautifully organize the wiring. I now have a compulsive need to do this for which I should probably be medicated. Still I'll wait until after the holidays and the main fix which started all this (new R2107).

My thought is that since the space is still tight, I could leave wires long enough to work on with the board outside the panel and then just use velcro to attach it to the wall on the left side. Is that a terrible idea?

Then one question from the user manual which states:
"If four-wire actuators are connected, the associated LED will begin to flash Red then turn solid Red when the end switch closes."
What is the end switch in this case? or will my red lights just continuously flash?

Rich_49

When the valve is open the end switch makes . There will always be a small yellow/green light showing the control is powered . When there is a call from a stat the corresponding grn / yel light will come on and a red light below it will flash . that red light will stop flashing when the valve is open enough for flow and when it becomes solid red the end switch has closed and the Taco relay will receive the signal .

Brent H.

Since it is currently functioning fine, I’d hold off until spring. Then if something goes wrong you aren’t without heat when you need it most.

pej2000

I have a few followup questions now that everything seems to be working.

1. The furnace is physically located in the garage which is underneath the 'great room'. Temps outside are now running under 10F at night/ 30F day. The garage is Very warm probably 80F. This seems new and I'm surprised that the system would waste so much energy. Now it's possible we just didn't notice it last year because it was a warmer winter and last year we did have the garage door sealed better to prevent mice which could have driven up the temps. The garage does have floor heating but it is turned off. Anything in this situation I should be checking?
2. This is a design question I guess. The master bedroom and bath are on the North side of the house with heat coming off the manifold. Those two zones have always lagged (which is generally fine for us as we like to sleep cooler). But since I'm asking questions....Is there something that could be done now or should have been done in the original design to remedy this? So right now I have the Masterbath set at 70F (for 3 days). The temperature has topped out at 68F. It's not dropping at night but definitely unable to hit its target. I have day and night temps on the R2107 set at 73F and 71F (little difference as our nights are colder and we get a lot of solar gain during the day). The reference temp is 135 (Max is 140 for floor heating) with offset of 3 (original setting by installer). We are at altitude 7000ft and according the the docs I have the system was modified for altitudes at 4500-6000ft. I don't think there are any adjustments to the Logimatic for altitude. It's a 123,000input BTU system in a 2400sqft house.

Many thanks for taking the time to read all this and any ideas.

pej2000

OK. Write a question and suddenly my brain turns on. How do I know the garage floor isn't getting heat? Check thermostat which reads 83F but is OFF. Touch pipes going into and out of garage floor. HOT! So this valve might be stuck Open? How do I check that?

Checked voltages at the Taco board: R1-R2 = 0; Y1-Y2 = 0

Not sure what to do next, but this could potentially solve both questions.

pej2000

Dug a little deeper. Shorted TT on the Taco garage floor zone. The actuator activates. Take out the short it seems to move back into original position.
So maybe I'm making up the problem. Pipes sure seem warm, but maybe that's all conduction from adjacent connections?

pej2000

Hours later after messing the the garage zone valve, the pipes are cool and other zones exceeding their set points!
Might be able to back down now on the R2107 Ref Temp or Offset. Will watch for a few days.

EdTheHeaterMan

I'm guessing that the radiant floor heat in the garage is in the slab. I'm also guessing that you do not know if there is insulation under the slab floor. So lets say the for some reason the garage floor only has perimeter insulation. (my masonry guy tried to pull that on my radiant floor slab, but I went to HD and purchased more insulation) That uninsulated floor with a shorted thermostat wire, left that valve open. now that floor would be like a big heat suction pump allowing large amounts of heat to dump into the ground under the garage, along with heating the garage too.

Is the rest of your radiant heat different from the garage? Staple up under the sub-floor or a thin Gyp-Crete pour over the tubing above the sub floor. Both of those will heat up faster that a 4" concrete slab, especially if there is no insulation under it.

So that garage zone will put a large load on the system and perhaps over tax the BTUh output of the boiler. Are you back on the R2107 yet? That will make a difference on how your system operates. I would not use the experience you have while the system was operating without the R2107 to gauge how adjust your system.

Just random thoughts of an old fart.

pej2000

Ed I really appreciate ALL of your random thoughts. In these weird times when help is thin, it's a real blessing to get the support to solve some of these things by myself.

The house is two slabs...one on a lower level for the garage and the second for the back of the house higher on the hill. The great room over the garage is (per the builder, now out of business) on iron beams. I don't know if that is concrete too but there is no 'subfloor'.

The new r2107 is installed and seems to operating fine on Automatic.

It seems like messing with the garage valve might have fixed a partially stuck open position. I'll wait a few days. Anxious to see what the temp in the garage is tomorrow (already dropped from 86F to 82F and pipes are cold).

Alan (California Radiant) Forbes

That Honeywell zone valve for the garage looks as though its had its motor changed out. Seeing that you've been having trouble with it, I would change the entire operator (silver box with cover).
https://www.supplyhouse.com/Honeywell-Home-40003916-026-Replacement-Head-for-V8043E-Zone-Valves

EdTheHeaterMan

I agree with Alan. but I want to tell you about a customer of mine from several years ago. My son goes to a call, just a month ago, from the plumber who recommended me to his customer, because he does not like to work on zone valves. Wires are just not his thing.

My son (who only works HVAC on the side now) went to help out the plumber and determined the wiring was just fine and the plumber should change out the valves. The plumber returned with only the replacement actuators 40003916-126 and spent too much time playing with the red and yellow wires and asked my son to come back to help out. Not the complete valve replacement as recommended.

Next weekend rolls around and my son found some old zone valves without the actuators in a pile of old brass fittings. He took them with to solve the problem. The plumber did not change the valves. My son removed the new actuators, then removed the valve plate but left the body on the pipe, he didn't want to get into the whole soldering thing. When the valve was opened up there was a small amount of schmutz in the valve body and the valve section was tight to move from the open to the closed position. By putting the new (unused brass parts from the scrap bucket) in the existing valve body, then placing the new actuators 40003916-026 back on the new valves sections the system operated properly.

So I guess I'm saying that you may need more then just the actuator 40003916-26 and the cost of the complete valve, compared to the actuator only, is not that much.

Just an old fart's ramblings for what it's worth

pej2000

Good story!
I can do this without soldering?

EdTheHeaterMan

pej2000 said:

Good story!
I can do this without soldering?

Yes, you can purchase a complete valve with actuator. remove the actuator, remove the valve plate, then discard the valve body. the do the same with the valve on the pipe (after draining off the pressure). be sure to get the o-ring gasket from the new valve properly seated on the existing valve body. Place the new valve plate on the existing valve body, then put the actuator back on. It is easy as that.



There are 3 dimples on the valve body so you can't get the valve plate on backwards. There are 2 different bolts that hold the valve plate on the valve body so you can't get them backwards either.

pej2000

Interesting.
Now the minor matter of 'draining off the pressure". I need to work that out, LOL. So far I've mostly looked at the electrical side.
I've seen some hose attachments that must be involved and some hand turned valves.
I'm imagining turning off water supply, releasing through a hose to the outside, change the valve parts, turn water back on, release air in the system through that air valve thingy with a screw driver?

Sounds fun. I love this stuff.
Maybe I should do all three Honeywell valves while I'm at it? They are all from 2005. Probably wait till spring if system continues to behave.

pej2000

While we are at it are these Wirsbo 4 wire thermal actuators on the manifold quality? They seem to be working so obviously not in any hurry to change them out.

EdTheHeaterMan

pej2000 said:

While we are at it are these Wirsbo 4 wire thermal actuators on the manifold quality? They seem to be working so obviously not in any hurry to change them out.

I believe they are fine for the purpose. Also the small Zone control boards that I remember selling with those valve actuators were pretty good also. I like your idea of leaving the wires long enough to pull the zone controls out of the small manifold compartment to wire them up and put them on a velcro inside the compartment. Just be mindful of the adhesive on the velcro so it does not effect the printed circuit board connections