Uponor zone control board fuse blows and relay is cycling every second

Billiambob

I think that I have two problems on my Uponor three zone control board (A3031003).

Problem 1: The unmounted actuator for zone one does not rotate even after being powered for more than five minutes. The board’s 4 amp fuse blows instantly when the actuator is rotated manually (the end switch is disconnected).

Problem 2: A relay on the control board is short cycling every second when a new Taco zone actuator end switch is connected. It does this when the actuator is in the open or closed position.

any ideas? Thanks

109A_5

" The unmounted actuator for zone one " is probably defective and should be replaced.

The " new Taco zone actuator " may not be compatible with this control module, it may draw too much current.

What happens if the " new Taco zone actuator " is left disconnected and you just jumper R1 to R2 of that zone ?

Billiambob

Thank you for your response.

Problem 1: I already tested both actuators using a temporary plug in 24VAC transformer and both operated normally. The motors rotated and end switches connected. I will repeat this again and measure the current draws. I will also get the draws with the actuators mounted in place.

problem 2: I will try the jumpers you suggested, thanks.

109A_5

" Problem 1: The unmounted actuator for zone one does not rotate even after being powered for more than five minutes. The board’s 4 amp fuse blows instantly when the actuator is rotated manually (the end switch is disconnected). "

The actual zone valve may be jammed so the actuator can't move it. I don't think it should blow a fuse when manually rotated.

Billiambob

The 24VAC transformer that feeds the Valve Control Board may be conflicting with the 24VAC control voltage being supplied from the 007 priority circulator transformer. Maybe that is why the connecting reply is short cycling. If there is a polarity issue between transformers and how can I test for it? Are all of the secondary outputs marked with dot marks to indicate hot? Does a red wire always designate the "Hot" wire and the white wire designate the "Neutral"?

Jamie Hall

With regard to your dots and wire colours. They should be. They often aren't. You have to check with a multimeter.

109A_5

Phase index dots are useless if no care is taken connecting the primary wires and even so if the transformer is built by another manufacture, yah never know. Even so if the secondaries of each transformer are only electrically touching at one point of a properly designed system the phasing should not matter.

I'm assuming this system once worked, maybe a flaw on my part, so my question is what changed ?

And your description of problem #1 seems to change symptoms with time, which makes no sense to me.

" Problem 1: The unmounted actuator for zone one does not rotate even after being powered for more than five minutes. The board’s 4 amp fuse blows instantly when the actuator is rotated manually (the end switch is disconnected). "

" Problem 1: I already tested both actuators using a temporary plug in 24VAC transformer and both operated normally. The motors rotated and end switches connected. I will repeat this again and measure the current draws. I will also get the draws with the actuators mounted in place. "

So problem 1 no longer blows fuses ? Or is the sum total of multiple incompatible loads causing an issue ?

Billiambob

Several technicians have tried to fix this system but without any luck. They changed out the very expensive boiler but I doubt that it was bad, (the shared water heater circuit worked just fine). At this point I’m not assuming that anything is correct. There are three separate systems each with their own thermostats, valve control boards, actuators and circulators. I found several wires connected between systems they just didn’t make sense. The system was not installed very well, wires were loose and not layed in very well. For now, one system still blows its fuse when the actuator is moved manually. The end switch relay still short cycles when either actuator end switch is connected. I bench test the actuators and that worked fine. I used a temporary power supply to verify that they could operate the valves, the draw wasn’t very much and both worked fine.

Right now I don’t trust anything to be correct. Soon I’m going to remove all wiring and carefully reinstall it. I will also verify that the 120VAC power hot and neutrals are correct.

Thanks for helping, Bill

109A_5

Well I'm sad to hear this went as far as a boiler change. Good troubleshooting would have isolated the boiler early on to prove it was not part of the issue. Seems you were dealing with salesmen and not good technicians. A Tech skilled in control system wiring should have isolated the problem and just repaired / replaced the defective part or wiring error / defect.

Rewiring may help since it basically requires reviewing most everything, especially if the system has been severely messed with. Find the wiring diagram(s) that best matches the equipment you have.

Keep in mind that even with rewiring it may not solve the original issue, and that may require further troubleshooting.

The Taco zone actuator(s) (depending on the model) may not be compatible with the Uponor three zone control board, you would have to compare the current draw of each.

Billiambob

Thanks for the heads up. I have a new Uponor 4 zone board and a new Taco valve actuator. I also have a 24VAC 3Amp transformer module and plan to bench test everything. I will measure the working voltage and current draw on each zone and test the "End Switch" circuit.

109A_5

Did this system always have Taco zone valves ?

If not why were they changed ?

What model are the Taco zone valves ?

Three Taco zone valves (depending on the model at 0.9 Amps each) could exceed the capacity of the 50 VA transformer in the Uponor documentation. So individually everything may be OK but when it is all integrated into a system it causes undesired behavior.

Sadly, IMO, Uponor seems a bit stingy with the electrical specifications of their equipment. I did find this for the A3023522 Thermal Actuator as an example.

Billiambob

Thanks again for all of the information, it is very helpful.

The original actuators were Taco made and have the same part number as the new ones. They are mechanical not thermal. When powered up the Closing Capacitor charges first then the motor runs to open the valve. When power is removed the Capacitor discharges to run the motor to close the valve. i measured the current draws to compare the new and original actuators. They are within specification and read about the same. Only two zones are being used on the uponor board so the transformer should be able to handle it.

I still believe that I have a polarity conflict when the End Switch contacts connect to power the Circulator . The End Switch Relay short cycles when the actuator End Switch is connected. There are three transformers is use. One is connected to the Uponor board, one is in the 007 Priority model Circulator, and one is on the Taco ZVC board (mystery connections from another heating loop). I will start with everything disconnected then reconnect one at a time to see what makes the Uponor board End Switch Relay short cycle and go on from there…

Thanks for the help, Bill

109A_5

OK I think I was unaware of the ZVC, anyway it really should not matter. The thermostats are basically switches that close when heat is desired. Either control board will do its thing, energizing the zone valve(s) and verifies the open zone valve with the closing of the end switch. Both zone valve controllers have a relay that closes its contacts with a valid, verified call for heat. ES on the Uponor and an Isolated End Switch on the Taco. If both control boards are used in the system, these contacts should be wired in parallel with each other and then connected to the R & W on the circulator, the X - X on the circulator then goes to the T - T on the boiler. There maybe aquastat in the mix but you have not mentioned it.

The thing is, at each connection to a different device there is a relay providing isolation so the transformer(s) can't interact with each other.

So a call for heat, zone valve opens, circulator starts running then the boiler is fired up.

Billiambob

Thanks a lot for your help.

I’m going back tomorrow to continue on. The information below is what I know so far….

This system is a little different because the home heating side does not turn on the boiler, (no electrical connections). The shared hot water heater circuit controls all boiler demands. The boiler primary loop provides heat to three separate loops for heating three levels (story’s). Each level has a separate zone valve control board, transformer and circulator. Each zone (room) has its own thermostat and zone valve(s) with actuator(s) to control hot water return flows from each loop.

The top level (loft area) uses a 24VAC Transformer, Uponor 3 Zone Valve Control board, 2 Taco mechanical quarter turn actuators with End Switch, and Taco 007 Priority circulator,

The mid level uses a Taco Radiant Mixing Block (RMB) and 24VAC Transformer. Identification and connections of the other associated components is unknown because they are not accessible at this time. Note; The system does appear to be working because the thermostats do make the system respond when the RMB is running. The only wiring connections visible are on the RMB and Transformer. A seven conductor cable is wired to the Transformer (R & W) and the RMB Heat Demand & Common (G & Y). The other end of the cable disappears into the wall. I will search again for these components.

The bottom level uses a Taco ZVC 406 Six Zone Valve Control board, Taco RMB, Wisbro 6 Outlet Supply Manifold, Wisbro 6 Position Return Manifold with 5 Uponor Mechanical Release Actuators to control the Return Manifold Pin Valves.

PROBLEMs

Both RMBs are not turning on. They will run continuously when a jumper wire is across the RMB Heat Demand / Common connections.

The mid level RMB Heat Demand input is connected to the G & Y wires in the seven conductor cable that disappears in the wall. These wires are also connected in parallel to the lower level Taco 6 Zone Valve Control board on Zone 5 thermostat input with a jumper on Zone 5 End Switch terminals. This might be a problem crossing over between systems. More troubleshooting required.

The lower level RMB Heat Demand input is connected to the Taco 6 Zone Valve Control board EXT terminals. This appears to be correct for “End Switch” operation. The crossover connections above may be impacting this system. More troubleshooting required.

The top level Taco Valve Actuators do not rotate when signaled. The Uponor Valve Control board voltage output to the actuators is 16.5VAC, (not the required 24VAC). It is the same with actuators connected or not. The 4 amp fuse also blows when the actuator is rotated manually. I suspect the board was zapped, I have a replacement board on hand.

The top level Taco 007 Circulator is not turning on. There are wires running between the Uponor Valve Control board End Switch terminals and the 007 Circulator R & W (1 &2) terminals. This appears to be correct. There are also wires going to the lower level Taco Zone Valve Control board Zone 6 thermostat input and a jumper on Zone 6 End Switch terminals. There are wires from the lower level Taco Zone Valve Control board EXT terminals. I don’t understand why these system interconnections are necessary. More troubleshooting required.

The Zone Valve Control board End Switch Relay is cycling (open / close per second) when either actuator End Switch is connected. There may be a conflicting path between system transformers. I will verify this when the new board is installed. More troubleshooting maybe required.

Thanks again for your help.

Bill

109A_5

Lot going on there, with a mix of equipment. Was this system built up from a box of random parts ?

Did all this actually work at one point ?

Things that seems the most odd to me;

" The Uponor Valve Control board voltage output to the actuators is 16.5VAC, (not the required 24VAC). "

Either there is a failing connection on the circuit board or something is seriously loading down the transformer. Is the secondary voltage of the transformer normal ?

" This system is a little different because the home heating side does not turn on the boiler, (no electrical connections). "

I would think the DHW would be too hot or more likely the CH water temperature too cold to heat the building properly when it is really cold out.

" The lower level RMB Heat Demand input is connected to the Taco 6 Zone Valve Control board EXT terminals. "

AND

" There are wires from the lower level Taco Zone Valve Control board EXT terminals. I don’t understand why these system interconnections are necessary. More troubleshooting required. "

Maybe I looking at the wrong ZVC406, I don't see a EXT terminals. I see Expansion terminals A, B, C to provide connection for Master / Slave setups of multiple ZVC406 units. And I don't think it is for the purpose of the RMB heat demand input.

It sounds like who ever was wiring up this system got confused and just stopped.

Also instead of paralleling the ES and Isolated End Switch contacts to control the boiler it seems they started to daisy chain from one control board to the zone 6 input of the other board. Which could work and provide a priority if needed.

If it was not cold out I say identify both ends of all the cabling, disconnect everything, get the appropriate manufactures wiring diagrams for all the equipment, make a plan and start over. Trying to troubleshoot a misguided attempt may not be worth the effort.

Billiambob

Thanks for the feedback.

My friend's daughter owns the cabin but needs to sell it ASAP due to a family medical problem. I'm an electrical engineer so they asked me to see what I can do. They don't want spend a lot but also want to make it right for the next owner. They told me that the heating system never worked very well and the down stairs bedrooms were always cold. They had several heating technicians try and fail to make it work. One of them even replaced the boiler (almost $10K) even though the shared hot water heater was working fine.

At this point I probably spent too much time trying figure out what and why things are the way they are. I agree with you, I think that it would be better now to just strip out the wiring and start over. Especially where wiring interconnects between separate systems.

l will bench test as many components as possible then sequentially test them again as they are being reinstalled. I will continue to verify operation of each zone as they are completed.

I must find the mid level system components to find out why they are not turning on the RMB.

I will replace the top level system Uponor 3 Zone Valve Actuator board and both valve actuators. I will test the Taco 007 Priority Circulator by putting a jumper between the thermostat inputs (1 & 2) . If good, I will connect the Oponor board "End Switch" Normally Open contacts to the Taco 007 Circulator thermostat input terminals 1 & 2 (R & W). This should turn on the circulator when either end switch closes.

I will rewire the Taco 6 Zone Valve Actuator board for normal thermostat inputs to each zone R W terminals. I will rewire the Zone Valve Actuator board 1 and 2 outputs and 3 and 4 end switch to the Zone Valve Actuators and test each Zone again. I will connect the Taco board's Isolated Switch Normally Open contacts to the RMB Heat Demand terminals.

Hopefully all of this will make it all work.

Thanks

Bill

109A_5

" They don't want spend a lot but also want to make it right for the next owner. They told me that the heating system never worked very well and the down stairs bedrooms were always cold. "

Without the thermostat / zone valve / circulator for the cabin's heat connected to the boiler it may always be cold. Typically there are two means of boiler control one for DHW and the water temperature of that process and one for heating the living space which is usually a higher boiler water temperature.

" This system is a little different because the home heating side does not turn on the boiler, (no electrical connections). "

Without the thermostat / zone valve / circulator part of the system being able to control the boiler I fear the system will never heat correctly. I'm assuming the boiler is the correct type and just not a hot water heater. Review the boiler's I/O manual for CH and DHW configurations.

This really should not be too hard to resolve as long as all the needed wiring is present throughout the structure.

Billiambob

I forgot to mention that there was a remote telephone control system to control a zone on the lower level system. The telephone module was partially disconnected and the RMB would not run. I was able to reconnect the original thermostat and jumper the RMB Heat Demand to run continuously to prevent freeze damage.

I also put a jumper on the mid level RMB Heat Demand to run it continuously too. The boiler is set to 165 degrees, both RMB Target outputs were set to 90 degrees and all thermostats were set to 95 degrees. I used these settings while we are gone to keep the zone valves open to prevent dead heading the RMBs. The whole house got very warm but nice, (average 75 degrees). The outside temperature ranged from 20 to 30 degrees. Note: The DHW has a separate mechanical mixer to regulate output temperature.

I agree that this not very well balanced and will probably over shoot a lot but if I can achieve the approximate set temperatures in each zone then I’m ok with that.

Thanks again for everything, you really know your stuff.

Bill

Billiambob

I finally figured out what was going on.

Problem 1:

The main floor Taco RMB circulator was running continuously. The main floor thermostats could control the heat in each zone but did not turn off the RMB when satisfied.

The loft heating system only had one zone valve working (out of two). At sometime while troubleshooting the Loft problem the main floor RMB stoped running. A wire trace found connections between the Loft Circulator T T terminals and RMB Heat Demand input terminals. This means that the Loft Circulator (boiler output) was also running the main floor RMB. I think that this was done because they also could not locate the main floor heating components. Original problem was probably none of the main floor zone valve “End Switches” are closing or the circuit board “End Switch Relay” is bad. The interconnecting wiring was removed. I’m still looking for the main floor heating components. Some closets were updated and maybe things got covered up then. I will disassemble what I can (within reason) to find it.

QUESTION: Is there a two wire 24VAC thermostat that can also wirelessly share control of the RMB? If this doesn’t exist can you please provide a (cheap) option or recommendation?

Problem 2:

The Loft Zone Valve Actuators are not moving. The system uses a 24VAC transformer (50VA), 2 Honeywell digital two wire 24VAC thermostats, a Wisbro (Uponor) 3 Station Zone Valve Control board, 2 Taco Mechanical 1/4 Turn Valve Actuators, a Taco 007 Circulator (with Priority). All wires are solid 18AWG.

The 3 Station board was replaced with a new Uponor 4 Station Zone Valve Control board and 2 new Taco Actuators. The actuators still aren’t charging or moving. The voltage to power (to open) the actuator is only 16.3VAC. The board demand yellow LED turns on but is not very bright. The input voltage from the thermostat is 1.6VAC with demand. The actuator opening voltage is 24VAC when the actuator is unplugged, (unloaded). Transformer power went from 26.5VAC to 23.5VAC when loaded.

A temporary 24VAC power plug module was used to bench test the original board and three actuators. Everything worked fine. The actuator running (opening) power is 23.8VAC (not 16.3VAC). The yellow LED was brighter and thermostat demand voltage was zero, (jumper shorted).

Question; Can the thermostat 1.6VAC (not zero) input affect the board yellow LED brightness and lower power to the actuator, (16.3VAC)? Would a mechanical thermostat switch lower the input demand voltage and raise the actuator opening voltage?

Thanks Forever

Bill

109A_5

" QUESTION: Is there a two wire 24VAC thermostat that can also wirelessly share control of the RMB? If this doesn’t exist can you please provide a (cheap) option or recommendation? "

Would a wireless thermostat controlling a DPDT (Double Pole Double Throw) relay work ? Or are you trying to have one thermostat control a local (hard wired) connection and another remote (wireless) connection ?

Seems like with all the different equipment in the system it was hard to maintain a normal control hierarchy structure and things got very muddy and dysfunctional very fast. And if there is hidden equipment, well that makes it even more of a mystery.

With the solid state switching devices such as Thyristors and the like common in modern thermostats, the thermostat burden voltage of 1.6 VAC should not be a problem. I would think the Uponor three zone control board (A3031003) would have enough buffering that the thermostat burden voltage would not be an issue to a zone valve load. However I have not found a good picture of both sides of that board to get a good feeling of the technology they are actually using for output switching. Although I only see one relay, so I believe that provides the isolated end switch functionality.

The question I have is when you see 16.3VAC at the zone valve what is the voltage of the secondary of the 24 VAC transformer at ?

The other thing is the zone valve you are using uses a form of switching technology that I remember I had an issue with in a post years ago. I'll try to find it to refresh my memory. The Uponor three zone control board (A3031003) may have a current limiting strategy that is ultimately incompatible with the switching technology of that style of zone valve.

109A_5

Seems the Uponor Thermal Actuator A3023522 as an example draws <0.3 Amps.

The Taco Zone Sentry Series draws 0.48 Amps while charging. If there is current limiting within the Uponor three zone control board (A3031003) it may disrupt the charging strategy of the Zone Sentry Series zone valves enough that they do not function correctly.

As a possible test, if you have a 24 VAC relay handy, buffer the Uponor three zone control board (A3031003) zone valve control output (Y1, Y2) with a relay, so the load of the Zone Sentry Series zone valve does not go through the Uponor three zone control board (A3031003). The Uponor three zone control board (A3031003) only sees the relay coil load.

109A_5

As a test does the inoperative Taco zone valves work correctly with the Taco ZVC 406 control module ?

Billiambob

Thanks for all of the suggestions:

This system ran before using these components so the ratings and applications are probably OK. The installed transformer voltage is 26.5VAC unloaded and 23.5VAC when loaded. I bench tested each component and measured it's operating voltage and current, everything was within specification.

The installed system with everything connected and while demanding heat the Actuators did not charge or move. The Actuator plug voltage is 26.3VAC when demanding heat and is unplugged. The Actuator plug voltage drops to16.5VAC when demanding heat and is plugged in, (but not mounted on the valve).

This same board on the bench worked fine. The only configuration differences were my 24VAC plug power supply (from a sprinkler system) and jumper on the board thermostat input, (no 1.6VAC from thermostat). All three Actuators operated normally. The power to the actuator was 23.5VAC while running and 24.3VAC while holding open. Clamp on readings for the whole board with actuators plugged in stayed below 350mA.

My next try will be to use the temporary 24VAC power plug on the installed board. There also may be a conflict with other installed components, (Thermostat, Circulator, Transformer). I will disconnect everything then reconnect and test everything one at a time.

Thanks Again For Helping

Bill

109A_5

From your description I get this (image below) when it is all connected in the system, there is an unexplained 7.0 Volt drop within the Uponor control board.

I would try; While measuring the voltage at the actuator, jumper the thermostat connection at the Uponor control board so the 1.6 VAC goes to 0. Maybe you have done this and I did not understand.

Billiambob

I appreciate the drawing,

Yes, it did put a jumper across each thermostat input (1.6VAC to direct short) and it didn’t change the 16.5VAC to the actuator.

Note: The Taco 007 Priority model circulator has its own control circuit and 24VAC transformer. Maybe there is a back connection that is conflicting the main transformer.

Thanks

Bill

109A_5

Still thinking the Uponor control board has some sort of current limiting function, and that is causing the 7.0 VAC drop across the Uponor control board. I doubt it is sophisticated enough to have some kind of Phase angle control.

109A_5

Where is the Taco 007 Priority circulator R & W terminals connected ? The ES terminals on the Uponor control board or a zone valve output (Y1, Y2) ?

Billiambob

Hello All

Problem Solved.
There was a conflict between systems transformers. I reversed the power leads from the Loft Heating system transformer connected to the Uponor Zone Actuator Control board R W. The board’s “End Switch Relay” stopped short cycling. The conflicting transformer is on the Bottom Heating system Taco Zone Actuator Control board. The board power was shorting when the actuator end switch closed. The reduced voltage would drop out the end switch relay then close it again without the short then short again and drop again….

The Loft Heating system is working fine now.

Problem 2

The Mid Level Heating Zone Control circuit did not turn on its RMB circulator. They could not find or access the Zone Control board, actuators, and zone valves. To get around this they connected the Loft Circulator T T terminals to the Mid Level Taco Circulator (RMB) input. This would run the Mid Level RMB whenever the Loft Circulator was also running. The Mid Level thermostats controlled the zone valves (assumed because areas heated with RMB running), but they did not control the RMB. I removed the crossover wiring between heating systems.

Soon I will resume looking for the missing Mid Level Heating components. I also created a temporary bandaid to wirelessly control the RMB, (if necessary). Hopefully this temporary fix will only be needed until I can fully access the snowbound cabin and also not require heat to avoid freezing.

Thanks to everyone for your help.

Bill

109A_5

Well I'm glad it is working better. As I believe was mentioned before, if everything is wired correctly the transformer interaction should not exist, there should be enough relays, isolated end switches an zone valve end switches that provide isolation and yet passes on the control to the next stage.

I'm guessing this system has such a mix of equipment manufactures, and that is causing the problem. Maybe the Uponor Zone Actuator Control does not have the needed isolation to play nicely with others.

Billiambob

Hello

The Loft zone actuator control board end switch relay stopped short cycling when the power transformer wires were reversed. The Bottom Level Taco ZVC transformer for zones 4, 5, & 6 was still very warm. I disconnected the crossover wiring between the Bottom Level system Taco ZVC board zone 5 input and the Loft Taco 007 circulator. The transformer is now much cooler. A combination of compromised circuit isolations and bad wiring put the two transformers in conflict. They didn’t work at all in opposition and did work while in phase but were very warm. Now both are working fine and are much cooler.

Thanks

Bill

Jamie Hall

I;m glad things got worked out at least enough to work.

One item of real interest here, for all of us: the comment that the two transformers worked when "in phase" but got very warm. We don't always recognize it — it's a bit of esoterica, really — but unless two transformers are identical, they won't necessarily be really completely in phase. Due to variations in exactly how they are built (the core, the way the windings are done, all that) they may be slightly out of phase — that is, the way the current and voltage on the outputs vary may not be exactly synchronized with each other. If this happens, then there may be quite a bit of circulating current between the two transformers, and this will cause heating (and, if extreme, failure).

Best practice is to never parallel two transformers, unless they are known to be identical.

Billiambob

Hello

Thanks for your input.

The cabin is owned by my friend’s daughter and she must sell it due to a family medical problem. The heating system has not worked correctly for years. She has had several heating repairmen try to fix it but without much success. One of them replaced the boiler even though the shared house water heater was working fine, (about $10k waisted).

I am a retired electrical engineer and I’m well aware of what you are saying and thank you. This system is a hot mess. There were connections crossing between systems that just didn’t make sense. I gave up trying to understand what was done and totally rewired the components that I could access. Parts of the Mid Level system won’t be accessible until spring. Almost everything is over twenty years old and many parts are obsolete. The zone valve actuators are the old Wisbro mechanical type mounted on Wisbro brass manifolds. The actuators and valves do not fully open. The end switches don’t close so the end switch relay does not close so the circulator does not run automatically. I’m told that the replacement Uponor thermal actuators will not properly mount on the old Wisbro manifolds (even with adapters - VR33). They say that the Wisbro manifolds must be replaced with Uponor manifolds. This is a no go at this time because the system still provides some freeze protection.

The Bottom Level thermostats are only partially opening the zone valves and don’t close the end switches. Jumpers were installed on all zone valve actuator end switch terminals to close the end switch relay to run the circulator. The Bottom Level system is operational enough for now.

The Mid Level system thermostats also partially opens the zone valves but I don’t have access to install the jumpers to make the circulator run automatically. The circulator (in garage) does run if a jumper is installed across the heat demand and common terminals. I looked for a pre built two wire (power stealing) thermostat that also has a wireless (RF not Wi/Fi) remote control relay or switch. This way the thermostat demanding heat would also remotely turn on the circulator . Apparently no such thing exists. Now I’m checking out push button remote control modules that could be added to the existing thermostats. If unsuccessful I will temporarily add a wire from the Bottom Level circulator to the Mid Level circulator so both will run at the same time. The effected thermostats will be set to avoid dead heading circulators into closed zone valves.

The Loft System end switch relay was short cycling and the Bottom Level ZVC board transformer was very warm. The Loft zone actuator control board end switch relay stopped short cycling when the power transformer wires were reversed. The Bottom Level Taco ZVC transformer for zones 4, 5, & 6 was still very warm. I disconnected the crossover wiring between the Bottom Level system Taco ZVC board zone 5 input and the Loft Taco 007 circulator. The transformer is now much cooler. Apparently through a combination of compromised circuit isolations and bad wiring the two transformers were either overloaded or in conflict. I saw what I saw. I’m still open to other theories but for now I’m done on this one.

Thanks

Bill