It's October in Alaska, and this video is the reason why I don't have to wear 3 layers to bed tonight. Much obliged, sir.

Thank you for sharing, I have normally replaced these heads without much thought into how they actually work, just that they didnt work. Trying to elevate my knowledge and understanding.

Good info, I know this vid is a few years old. Yet terminal 2 and 3 is a dry set of contacts does energize the zone valve. Just closes the boiler start circuit to activate boiler. The most misunderstood part of this zone valve it no common only a hot leg terminal 1. Terminal one gets 24 vac and heats the internal wax, and the unit grounds the low voltage common. Sometimes the end switch could be completing the boilers common or millivolt circuit. Good information in your vid to help many understand this valve

Thank you for sharing this great video. Please make the next one showing the content of the heating cylinder. In this cylinder there is what appears a mixture primarily of copper powder and possibly clear silicone or grease to hold it together that when heated produces the thermal expansion/force neccessary to drive the exposed cylinder pushing the water base-valve to it's open position when the thermostat calls for heat ....... I believe these valves could have been replaced by a better one and less expensive (without the problem of damaging it when tested with 24v outside the basevalve) a very long time ago knowing how innovative we are in the USA but I am sure Chinese as inventive as they are from way back in time will surpass us soon. The big brick/mud stores, cloud stores, but first in line private patents may be blamed for the higher prices. Once again thanks for the nice video.

Great video, thank you

Thanks Jarred. Video is one of the few that addresses the internal working that I have seen. From a Taco manual. This is (what I believe) is an accurate description of what the white contact switch does. It is not a over stroke sensor as you suggest in your video. An interruption of current to the power unit heater occurs in the fully open mode because the outer blade of the heater switch is deflected causing the heater element to open, interrupting the 24 VAC power from flowing through the heater wires. As the piston retracts slightly, the contacts on the heater switch meet again, resuming power to the heater wires wrapped around the wax filled element. This slight back and forth motion is repeated as long as the thermostat contact is closed.

@obbiepet1036

2 жыл бұрын

@@7LegSpiders Would you agree that the main reason for that contact controlled by the little plastic tab is to prevent the continued heating of the wax after the piston reaches full stroke? On the power head I have been looking at, it isn't mechanically possible for the piston to extend beyond the base of the power head. Its locked in by the frame of the power head. I have been playing with a broken power head where the piston moves freely so I can see what's happening without hooking it to a 24V volt supply. Best, Obbie

@obbiepet1036

2 жыл бұрын

@@7LegSpiders I continue to mess with my broken power head and took it apart today similar to what you did with yours. I actually pulled the piston out and used a lighter to heat up the wax to see it expand up the tube that holds the piston. Pretty interesting. I don't think your right about the limit switch preventing over extending of the piston. Here is why. The contact for that plastic nub is closed when normally cold. It opens as the nub gets displaced by the piston end moving forward. That contact when made cuts current from moving to the wax heater. On my power head, the piston head is a cone so the contact falls back to the normally closed position when the piston over extends (plastic nub passes over the bottom of the cone). This re-enables the circuit and will continue heating the wax. At that point its a smoke generator.

Thanks!

We have a VERY old taco valve, it's the "green top" that predates the gold top valves. Can I take the power unit off a gold top and use it on the old green top? They look almost identical.

what is the difference between a Normally Closed ZV and a Normally Open ZV..? Thanks

Thanks for the video. when I manually open my valve, it fires my boiler. I have three zone valves and this only happens on one. Seems wrong

Hello, I have the two wire round mercury thermostat. I want to add a nest 2020 version. Its asking for a c wire. Im in a condo where we have radiated heat. The taco is in a bedroom closet door opening and the red wire is attached to the top of the taco and then goes to the thermostat. The white wire is on the middle leg on the taco ZV and then goes to one of the the transformer legs and the other leg of the transformer goes to the thermostat. Its works just fine using the round mercury thermostat. I bought (Google Nest Power Connector - Nest Thermostat C Wire Adapter - C Wire Adapter for Smart Thermostat ) and I wired it as expected - pretty simple...and it appears to work on the nest thermostat and when I turn it up its says its heating...BUT its not. I went to the closet and when the nest says its heating...the pipe is not hot. It not opening the taco ZV. The wiring is good and I made sure its connected correctly. But it just doesn't open the Taco ZV. I undid everything and all is fine with the mercury thermostat. I want the nest to work but can't figure out why it won't open the zone valve. I noticed that there is a third wire (green) that's just wrapped around the wiring but not being used on the both sides of the wire (at thermostat and at ZV) and thought that connecting that green unused wire to the third leg on the Taco valve may be the c wire I need. What is the third leg on the ZV for? Does that provide 24 volts of power and is that considered the c wire? TIA for your assistance.

@SamFowler9969

2 жыл бұрын

@@7LegSpiders LOL....Thanks man maybe the delay is what's happening and I am not waiting long enough. I agree - I should just stick to the good ole trusty mercury switch and keep my privacy if possible. Funny thing is - is we all want the latest tech and latest features but at a cost of our privacy. Time to buy a firewall now. LOL

are you able to solder that wire back on to fix it or is it junk at that point?

@bjmsamrlm

4 жыл бұрын

I tried but was unsuccessful. The yellow "wire" is a bundle comprising two thick wires twisted around a thin wire. The two thick wires terminate at an "ear" of the pad beneath the cylinder to help maintain tension on the thin wire which goes on to wrap around the cylinder and serve as the heating element. I managed to get the thick wires situated but was unable to solder the thin wire (silver?) so twisted the ends together and confirmed continuity (~22 ohms). Once reinstalled and energized, the element activated but the valve did not open and the head failed again in the same way, suggesting that the broken wire is a symptom rather than the underlying problem.

@trankt54155

4 жыл бұрын

@@bjmsamrlm yes, you are right. The two big wires are there to stabilize the heating element wire and that heating element wire could be made of tungsten or other heat generating metals....that generate heat when a current is applied. I have not seen any replacement wire for that...have you?

@trankt54155

4 жыл бұрын

@@bjmsamrlm Get a pair of pliers and push down on the spring loaded tip of the valve to see if you are able to push it in; but if you can't then the valve is stuck and that is why the electromechanical head does not have the force necessary to open the valve...

@bjmsamrlm

4 жыл бұрын

@@trankt54155 The valve was fine and a new head resolved the problem.

OK, makes sense....I probably wrecked at least one of these things this way

Good video BUT a correction needs to be made to the end of your video in that the second switch (located on the bottom with a plastic sphere on contact with the brass cone would not go beyond the limits of the cone to drop down so the switch would close and allow the continuous heating of the coil and so it would burn off as you alluded to. The contact points of the coil at the pcb board is the result of cooling and heating stress and eventually separated and NOT because of the switch that closes as the result of the plastic sphere passing beyond the point of the brass cone; it is not the case because when the manual lever is in closed position the cone cannot move beyond the limit of the cone excursion areas to cause the metal slap with a plastic sphere to drop out of the brass cone---and hence creating the continuous circuit as you postulated. Even if you test the actuator when it is not affixed to the valve mechanism, and thus not constrained by the loaded spring of the valve, the piston does not rapidly shoot out of the cylinder and so the metal strip with the plastic sphere would not come off contact with the cone to make the switch continuous...to allow the coil to overheat. When the plastic sphere moves to the max position of the graduated cone the switch becomes open and thus disconnecting power to the coil which would stop the heating and the cooling begins gradually and the loaded spring in the valve mechanism would push the piston back gradually as the oil cools and contracts----hence the previously excursed distance (very short) shortened and the cycle begins anew. This is a negative feedback design for this particular switch. Another switch right above that (black color) is a positive feedback switch because as the piston moves out it effectively disengages and creating a short circuit between #2 and #3 creating a loop signal for the burner and the circulating pump to turn on now that the pipe valve is open by the piston actively pushing on it.... If you test the head for its electromechanical functioning in situ the excursion distance of the piston is confined by the spring loaded lock of the valve. Keep in mind the piston excursion of the whole hydraulic cylinder and piston is only a few millimeter...not very much and you can measure it by measuring the distance of the manual lever from close to open positions. Check the manual level position and you would know what I am saying.... Thanks for disassembling the device and making the video. Very instructional...

@trankt54155

4 жыл бұрын

Another scenarios that could cause the heating element of the head to fail from excessive burning/heating is that the piston is UNABLE to expand pushing against a stuck spring loaded valve that may be corroded through exposure to heavy water chronically because the generated force from the heated oil/fluid in the cylinder is unable to overcome the resisted corrosion of the valve and thus the circuit with the plastic sphere sees no movement from the cone and thus the power continues to flow into the heating element and the circuit mechanically would not separate to open by the mechanical cone movement----hence the result is the melting away of the heating element form excessively generated heat. It is best to take a pair of adjustable pliers and clamp down on the tip of the spring loaded valve and see if you can PUSH down on the valve manually with the pliers and if you can't do not put in another electromechanical head because you would cause it burn off and waste money. It is then you would have to replace the ENTIRE valve apparatus by sawing off both ends and replace with a new valve apparatus....

@trankt54155

4 жыл бұрын

@@7LegSpiders The piston cannot escape if the manual lever is in the closed position, period. Go test that statement. with your dismantled head. You can apply voltage to lead one and wait for 90 seconds for the pistons to move out and once it comes to the max of the cone the switch would turn off the power to the coil. You can argue all you want and it wont change that fact. I am just pointing out what you said is incorrect so the viewers are not under the thinking that what you said at the end of the video is causing the death of the head. I know this is KZread and people can say whatever they want...and you certainly can do that too...

@trankt54155

4 жыл бұрын

@@7LegSpiders The only way for the cone to extend beyond its limit and thus allowing the switch to close (thus creating a continuous circuit) as the result of the switch flap with a plastic sphere to fall off the cone is when the manual level is on the OPEN position, or can be seen you put it there. Look at that frame carefully and you tell me if that is not the case. The cone cannot come out if the manual level is on CLOSE, period (you can check it with your head to verify that. BUT even the manual lever is on open and you test by connecting lead#1 and lead#2 with a 24 battery as the oil heats up and expands the piston would gradually come out and as it comes out it would push down the switch flap with a plastic sphere and that would cut off the power supply circuit to the coil and thus the piston will not move out further because the oil may not expand further due to the fact that the heating coil is no longer heating.... You can pull out the head you disassembled and verify mechanically what I said. The switch flap plastic sphere got there at 2:28 because YOU put it there with your finger.

@thefish8002

3 жыл бұрын

@@7LegSpiders Whether or not the thing can overextend, I'll take your word on it, and not energize it with the power head off. It was 10:30 PM when I decided to do dishes and realized I didn't have any hot water. Never messed with these before, but your video confirms what I was thinking. Many Thanks! In my situation, when I manually override the valve, my boiler still doesn't fire up. For my morning shower, I think that I'll just have to jumper terminals 2 & 3 to light the boiler with the valve jacked open. Thanks again for your video, much appreciated.

Good video. If you resolder that yellow wire, will it start working again? Sounds like an easy fix, instead of spending $80 to $100 for a replacement. (BTW, I talked to a Taco tech rep a few years ago--very knowledgeable guy who had worked with the inventor of this zone valve. I believe he told me that it's wax inside the heated canister.)

@johngnipper1454

4 жыл бұрын

Bees wax i think

@trankt54155

4 жыл бұрын

@@johngnipper1454 Does beewax expand that great amount of volume when heated? What ever the material it must expand enough volume and exert greater amount of force to overcome the point of the spring loaded valve to open it..

If you want to make some informative videos , why don't you get yourself a tripod and make a decent views of it instead of excuses for shaky picture Don't you do editing before uploading your stuff , geeeee that is ,,,,,,,

@superbcomplex

4 жыл бұрын

Se Faucon... relax bro, it’s totally fine. Jarred, good video. It helped me!

@sefaucon3839

4 жыл бұрын

Berry Blanton 👍😋