How to replace a Honeywell zone valve with a different manufacturer's valve

mcho

I have 7 Honeywell V8043E1012 zone valves on a hydronic system using a "Laars Mini-Therm II" 125,000 BTU boiler where I am constantly replacing the motor heads at 70-80 dollars a pop (and that with me doing the work!). I probably have spent 700 dollars so far in the last 10 years. In each case when I dissect and diagnose the problem it is the failure of the end switch. All the motors work but you can't buy the end switch separately. I will never buy anything with "Honeywell" on it again either at home or at work!!

I have finally had enough and wish to replace the valves with something else (I heard TACO's were reliable but suggestions are welcome).

My problem is that I do not know enough to match them up; to replace like with like between companies. I know my valve has 3/4 sweat fittings, is a "two position valve" (open and closed?) and requires 24 v (don't they all?). Seems simple enough.

But I noticed my fuse is a 2 amp fuse and I do not know what it is protecting (there are no electronics on the boiler). I presume the pump motor and the motor valves?

ANYWAY, does it matter which valve I get as long as it is 3/4 inch? How do I determine which valves from TACO or someone else are a match for my system? Is there something on the Internet somewhere that explains how to spec a zone valve? I would even be willing to take a course. Given that the system was installed by monkeys originally, these might not have been the right valves to begin with and that is why they are failing.

I used to be an ironworker (so I know how to work with my hands) and am now an engineer and can understand technical and mathematical information. I am pretty good at plumbing too (not that different from welding), which is why I do this stuff myself.

Jamie Hall

"I diagnose the diagnose the problem it is the failure of the end switch".

Before you start swapping out valves, find out why the end switches are failing. I know it's nice to rave at the company, but it's not always their fault. How much current are those switches switching? At what voltage? And is that within -- well within -- their rating?

If I see chronic failures in a switch, that's the first thing I look for.

HomerJSmith

Taco Sentry Zone Valve for Honeywell ZV--How to
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Taco-Z075C2-1-Install-Instructions.pdf

You can buy micro switches 15 or 20 Amp from Allelectronic.com for cheap. Just make sure the case style is the same. Solder it in place of the bad one. How do you know that it is the end switch?

Maybe it is the motor? Maybe it is the current, too low. A honeywell gobbles up 7VA per valve. Is your transformer big enough to handle the load?

mcho

Thats a good point. But I am not sure how to go about doing that as a practical matter since there would have to be an ammeter in the circuit at the time that the valve opens. There are two wires going into the switch. I would have to disconnect one of them insert the meter into the circuit and then call for heat (not trivial since I live alone) while I am standing there watching the meter.

Of course I am inexperienced so is there some practical way to do that? You are probably right because the fuse as had to be replace three times in the last ten years.

I would like to still like to learn how to spec a zone control valve. Or do I just call the boiler manufacturer? Seems like the size of the zone might matter

HomerJSmith

The maximum # of Honeywell ZV on a 40 VA transformer is 5.

The transformer on a boiler is there to provide power to the boiler relays not necessarily to zone valves. The boiler manufacturer will sometimes tell you in their literature how many ZVs that their transformer will service besides what the boiler requires in terms of current. If you exceed that you need an auxiliary transformer to handle the extra load.

As each zone gets activated, you are drawing more current.

mcho

Thank you HomerJSmith. I know the end switches are not working because when I press the little button the resistance continues to be very high across the wires (its been a while so can't remember the reading). I then applied voltage to the motor and it turns. Thats my diagnosis technique.

Based on what you say the current draw through the switch with the switch open should be no more than 7/24 amps. right? You are suggesting that the switch may be burning up?

So I believe (not sure) that the switch runs the circulator pump and the furnace will not fire if the circulator pump is not running. So there has to be a problem withe relay that starts the circulator pump if there is a high current flowing through the end switch. Am I getting any of this right?

mcho

Yes there is an independent transformer. I'll check the specs on it.

No info on it other than 120 volts 50/60 cycles. It has a number A1720 1693 but a goggle search bore no results. It receives power directly from the outlet. But I can disconnect one of the leads and insert an amp meter. So I will do that. It is quite hot but the furnace is running. I suspect its the right size because it is three times the size of the boiler transformer.

But I am confused. How can low current output of the transformer affect the end switch? Doesn't the current going through the switch depend on the current draw of the pump activating relay? Isn't the switch failing because of too much current?

hot_rod

Is the end switch wired directly to a 120V pump circuit by chance?

It is always preferred to wire the valves through a relay box, that eliminates most of any end switch issues.

We offer an easy to retro fit zone valve with union and press connections, no soldering necessary. Z45PL in 3/4 press

We have a 5 year warranty on the relay box and zone valves.

We switched to a reed switch several years back to eliminate micro switch issues. a reed switch is a hermetically sealed switch activated by a magnet instead of a cam, so less issues as the switch ages. B, but we suggest you wire through a relay box still.

https://www.caleffi.com/usa/en-us/catalogue/z-onetm-relay-multi-zone-zvr103

Jamie Hall

It's worth remembering that the output voltage of a transformer will drop with increasing load. Depending on the transformer, this may be appreciable. From all you are describing I'm seeing a situation where something is drawing too much power from the transformer (hence the blown fuses -- they are protecting the circuit correctly, but the circuit is being asked to do things it shouldn't) and the voltage is dropping. This can cause all kinds of havoc. Would it be possible to draw a circuit diagram of the complete control circuit?

mcho

Yes Jamie Hall. I have attached the schematic from the boiler manual, and from what I have been able to deduce so far, the wiring is pretty much the way it is shown in the schematic. This also answers the previous questions about the end switch going to a relay instead of the the pump directly. Its a mechanical relay, not an electronic one because this boiler is more than 20 years old. I am glad of that because mechanical relays are very reliable.

Thank you Hot Rod. I have read good things about Caleffi valves and products on this forum. But if I replace the valves I still need to know which Caleffi valves would replace the Honeywell V8043E1012.

HomerJSmith

Are you reading the number on the Transformer correctly ?

"But I am confused. How can low current output of the transformer affect the end switch?" It doesn't but low power to the motor maybe to low to activate the end switch. Yes, the the relay that turns on the pump and fires the boiler, current draw goes thru the end switch, at least some current.

If you touch the two red leads on the zone valve together the boiler should start and the pump run. Then if you depress the little button on the end switch and nothing happens then the end switch is toast. Simple. Take an end switch apart, the top just pulls apart, and look at the points, are they burned? If burned, something is drawing to much current. Time to look at the boiler control or whats between the ZV and boiler.

Zman

The issue with the Honeywell valves is usually that the motor does not open far enough to engage they end switch. A bad motor and or inadequate transformer is often the issue.

As mentioned above, I would look first at the transformer.

I have become a big fan of zone controllers. It makes it super easy for the tech or the customer to diagnose zone issues and cleans up the wiring.

For residential applications you are looking for 24 volt normally closed, power open valves. For high flow applications look for a full port valve.
Calleffi makes a nice valve.
The Taco valves with the led lights are nice as well.

HomerJSmith

All the red wires should connect to the R-W connectors on the control board. The transformer on the schematic can only handle the control board, gas valve and vent damper motor if you have one. All the ZV must be run on a separate TFMR of at least 60 VA, assuming you don't have current robbing thermostats (I haven't seen one of those in a long while). You might just replace the relay on the control panel with another 24V double pole/double throw relay, just in case. Jard 92340-Honeywell R8222D1014 or White Rogers RBM 90-340.

Where your ladder schematic shows "Zone Pump Relay 4", that line across is the load on the end switch. There is no reason for the end switch to burn. If the end switch is burnt, there is a wiring problem somewhere. If the relay coil is shorted, I would expect the primary on the transformer to open. Relays are cheap, replace it. Where is the fuse that blows, I don't see it?

Robert_25

I understand that you are frustrated with the current brand of zone valves, but your failure rate is not even close to normal. I have some of those Honeywell zone valves over 10 years old, and they have yet to be opened.

I agree with the others that you need to get a transformer that is correctly sized for the load, or just add a second transformer and split the load. You will likely need to do this even if you change to a different brand of zone valve.

mcho

Edit: Thank you all for your terrific advice. It was VERY helpful. I fell more confident about what I am doing. The people on this forum are AWESOME!!

UPDATE: I took one of the failed motor heads and rechecked it only this time I removed the micro switch. It is rated for 10 Amps and 250 volts. The output is rated for 11 amps, 1/3 horsepower and 120/250 VAC. I don't think the switch failed because of too much current draw. The amount of heat generated by more than 11 amps would have melted the thing. There is absolutely no indications of overheating (it has a plastic housing and it is pristine). Given all the complaints about these things failing that I have found on the Internet I have to assume its just junk that breaks after its switched X number of times.

I'm going to go ahead and replace the valves. I finally found a NATE certified tech in New Mexico!! I have them coming over in two weeks to figure out why the fuses are blowing and replace the 20 year old relays. Probably should replace the 20 year old pump too although it works flawlessly! But I can do that myself. I will also replace the valves myself.

HOT ROD: Can you tell me what model I need?

Zman

mcho said:

UPDATE: I took one of the failed motor heads and rechecked it only this time I removed the micro switch. It is rated for 10 Amps and 250 volts. The output is rated for 11 amps, 1/3 horsepower and 120/250 VAC. I don't think the switch failed because of too much current draw. The amount of heat generated by more than 11 amps would have melted the thing. There is absolutely no indications of overheating (it has a plastic housing and it is pristine). Given all the complaints about these things failing that I have found on the Internet I have to assume its just junk that breaks after its switched X number of times.

I'm going to go ahead and replace the valves. I finally found a NATE certified tech in New Mexico!! I have them coming over in two weeks to figure out why the fuses are blowing and replace the 20 year old relays. Probably should replace the 20 year old pump too although it works flawlessly! But I can do that myself. I will also replace the valves myself.

HOT ROD: Can you tell me what model I need?

Did the switch you pulled out work?

Complaints from the internet? Seriously?
Everyone has complaints on the internet.

mcho

ZMAN: No it did not. It had infinite resistance (0.L) either way. My DC power supply won't supply more than 18 volts at 1 amp draw when I hooked it up to the motor, and either the motor is also bad or that is not enough to turn it. What I found inside was a liberal patina of oxidation on all the parts as if they had gotten wet. When I tried to open the valve manually it required a lot of force, almost enough to be painful. I think we are getting closer to the problem.

I have 5 more bad valves in then shed. I will take them all apart tomorrow and see what's up. Maybe I can repair them. I do computer electronics as a hobby so maybe I can fix the microswitchs also.

I just want to be DONE with this darn heating system!! Its been a 10 year ordeal. And until today it was impossible to find a competent technician in Santa fe.

HomerJSmith

It's nice you have so much money to spend. I recommend Taco Sentry ZVs . They have a high CV and operate on a charged capacitor with extremely low current draw. (more valves per transformer)

HomerJSmith

Take one of the shed valves connect an ohm meter to the red wires and connect the yellow wires to the secondary of 24 V transformer. Look at the motor turn and make contact with the micro switch. Read the ohm meter.

The lever does take some amount of pressure to open the valve.

Fun Time.

mcho

HomerjSmith: I couldn't tell you about having a lot of money to spend. The local heating companies have robbed me blind and really screwed up my system. They have shown themselves to be completely incompetent.

It does not match even remotely the manufactuer's instructions or any other hydronic systems I have studied. For instance the manufacturer clearly states that a second pump is required for the zones. No second pump. No secondary system. Wrong temperature in the boiler, no bypass valve, no outside thermostat or control board, no trap in the gas line... and much more. Thats why I do everything myself now. In Santa Fe you have to.

Jamie Hall

For what it's worth at this point -- and I'm glad you've found someone who might really know what they are doing! -- one thing to remember about microswitches: if they are not fully tripped one way or the other, the contacts can become badly burnt even at currents way below the rated values. In this instance, if your zone valves are underpowered, which seems likely, they will move slowly and may not be able to complete their travel. This could easily lead to the switches not being fully tripped, which in turn could lead to their early failure.

mcho

Thanks Jamie Hall. You are quite right. I won' replace the valves until the NATE tech does his thing. At least with two people we can measure the current at the valve.

HomerjSmith: WOW!!! You were right I had no idea the TACO and Caleffi were that much more expensive than Honeywell. I need to listen to you guys!!

HomerJSmith

I wish you would have come here first before spending a small fortune. The advice here is free and contributed by heart felt professionals with much over 100s yrs of cumulative experience.

I'm cheap and, by nature, I only do what is necessary to get a system up and running and operating as it should, that's what I meant.

Replacing ZVs is a big thing, even pro-fit and at $100 ea that's $700 + labor. But, it's your call.

Honeywell ZVs (8) on my old sys lasted 27 yrs and nary a leak or problem. I've had to replace powerheads on other sys, but it was easy and fast.

Let us know what happens, I'm always curious.

mcho

HomerJSmith said:

Where is the fuse that blows, I don't see it?

Its there but as an unlabeled rectangle in the wiring diagram on the 24 volt output of the transformer in the same position as where it is labeled on the schematic. Believe me I have studied this schematic for hours (not my area of expertise).

This information is extremely valuable. THANK YOU!

HomerJSmith

If you want to compare prices try Supplyhouse.com

mcho

HomerJSmith said:

I wish you would have come here first before spending a small fortune. The advice here is free and contributed by heart felt professionals with much over 100s yrs of cumulative experience.

I'm cheap and, by nature, I only do what is necessary to get a system up and running and operating as it should, that's what I meant.

Replacing ZVs is a big thing, even pro-fit and at $100 ea that's $700 + labor. But, it's your call.

Honeywell ZVs (8) on my old sys lasted 27 yrs and nary a leak or problem. I've had to replace powerheads on other sys, but it was easy and fast.

Let us know what happens, I'm always curious.

Yes you are right. Never had a problem with being ripped off anywhere else. Back when the valve problems started 10 years ago, I didn't know this forum existed. I didn't even think to look because I just trusted the people doing the work. I know professionals like you exist everywhere else but it is extremely rare in New Mexico.

We joke about needing passports when we go to Colorado! Its like living in Mexico but not as good. Most contractors here do not know what ANSI or ASME are.

I will be doing all major replacements myself so labor is not an issue. I am just having the NATE tech do the electrical diagnostics, and combustion gas analysis (assuming he know how). Also the last guy left a gas leak by the gas valve (really tiny) that needs to be fixed by a gas technician. Fortunately I bought something he didn't have. A gas leak detector! I used to teach bubble leak testing at work which is why I don't trust it. Its more art than science.

MikeL_2

I've found it important to check the resistance of the valve ball connector / bushing on Honeywell zone valves - with the motor removed from the body of the valve, try rotating the valve by hand .......

mcho

MikeL
Yup did that already. Very easy to turn even when there is flow. Just with my finger tips.

hot_rod

You will find most spring return zone valves like HW, Erie, WR Caleffi, etc have a Cv in the 7-8 range.

Really no need to have a higher Cv on a 3/4 zone valve knowing that 3/4 copper can handle 6.6 gpm at 4 fps?

Higher Cv maybe for the pump and dump GEO guys that flow 10- 15 gpm sometimes and need high shut off pressure rating.

There were a bunch of bad micro switches out there for a few years, all brands suffered through those bad batches. It sometimes takes years for bad production runs to work out of the system and off the supplier shelves.

Micro switches AKA vending machine switches, are not ideal for switching digital signals that we find more and more on boilers and other HVAC equipment. We went to a reed switch at Caleffi as it handles both the low current draws and via a relay box high current, so we solved the two most common end switch problems with a sealed reed switch.

The third most common end switch failure is caused by contaminates getting on the silver contact points. the contacts arc, and fail. Chemicals stored in the room, flue gas by products, even real humid conditions can be a problem with un-sesled switch contacts.

If you do want to switch to Caleffi we have sweat, press, pex, flare and threaded bodies to chose from.

The Z-One series
Z45 is a 7.5 Cv 3/4 sweat, Z 45P is a press connection 18" wire leads

If you prefer terminal block wiring Z55 or Z 55PL press.

HomerJSmith

Ah! I see the fuse on the secondary of the 24 V Transformer. If that is blowing, it means that the secondary circuit is drawing more current than the fuse is rated for. It is NOT the end switch that is drawing the high current. In NEC (National Electrical Code) parlance, a switch is a device and a device draws no current, although it is in the circuit. Anything labeled a 'switch' is a device.

Look for a ground fault (short to ground) on the board, relay coil, vent damper motor, aquastat, or gas valve and the wiring between the end switch and control board. If the wiring and circuit board is sound, look for something that is pulling more than the rated current, that would be vent damper motor, relay, gas valve. Anything that consumes current. The coil on the relay is usually visible and if the wrapping around it is burned and very discolored, the winding maybe shorted.

This is the analysis on the fuse blowing.

mcho

Thank you Hot Rod.
Are the gears metal of plastic? I couldn't find the info in the spec sheet. On the Taco spec sheet they are plastic.

After 25 years of radiological engineering in nuclear power plants I have learned not to trust plastic gears and to overbuild everything. Our motto is "belt and suspenders."

Most mechanical things that are utilized well below their specs tend to last a lot longer!

Which makes me ask it the 6442-6443 series would be usable in this application? I like that they claim to have minimal pressure drop and can handle higher power levels. They seem to be commercial grade versus residential grade. I want commercial grade even if it costs more.

HomerJSmith

Well, one does have to be careful when dealing with a nuclear power plant. One doesn't want a China Syndrome.

I have never had the plastic gears in a ZV fail, it is always the motor of end switch. Caleffi valves are long lasting.

Note! All the ZVs and thermostats should be run off the secondary transformer and only the red wire from the end switches connected to the R & W terminals on the control board.

hot_rod

mcho said:

Thank you Hot Rod.
Are the gears metal of plastic? I couldn't find the info in the spec sheet. On the Taco spec sheet they are plastic.

After 25 years of radiological engineering in nuclear power plants I have learned not to trust plastic gears and to overbuild everything. Our motto is "belt and suspenders."

Most mechanical things that are utilized well below their specs tend to last a lot longer!

Which makes me ask it the 6442-6443 series would be usable in this application? I like that they claim to have minimal pressure drop and can handle higher power levels. They seem to be commercial grade versus residential grade. I want commercial grade even if it costs more.

Since you have an appreciation for fine design, let me brag about the Caleffi Z-one valves.

We actually have a small gear train inside, 4 gears provide a 20- 1 ratio. Some gears are hardened steel, the motor pinion is brass, and others are glass reinforced composites.

The main difference with Caleffi is the lost motion gears. By unloading the motor and spring tension from the gear train we eliminate that impact when the spring pulls the valve closed.

We learned by watching other brands with slow motion video cameras what caused zone valve bang, and wear on gear trains. The lost motion is sort of like pushing in the clutch petal on a standard shift transmission, the engine and driveline disconnect, the lost motion does about the same function.

The lost motion also gives that delay on open and close.

The gears are about 1/4" thick, no stamped sheet metal gears like you see in other brands, the one pic shows the difference..

We use a coil instead of compression spring, each one is wound with a torque meter at the factory. The coil type spring provides a more constant torque from full open to full close, this too eliminates ZV hammer.

Also some shots of the end switch design.

Important to know switch minimum current ratings, most folks only look at max current draw. Minimum is critical with electronic controls, relays and digital signal switching. The industry calls that sealing or wetting current.

Without a low end rating low enough the micro switch contacts do not seal tightly and that causes some of the premature failures.

I would not recommend the 644 series ball valve zone valve. Too $$, needs power open and power to close, and the z-one is "uber" engineered to do exactly what you need.

mcho

HomerJSmith said:

Well, one does have to be careful when dealing with a nuclear power plant. One doesn't want a China Syndrome.

I have never had the plastic gears in a ZV fail, it is always the motor of end switch. Caleffi valves are long lasting.

Note! All the ZVs and thermostats should be run off the secondary transformer and only the red wire from the end switches connected to the R & W terminals on the control board.

Thank you HomerJSmith. You technical advice has been extremely helpful. By the way I cut and paste all your posts (those of some of the others) into a document on my desktop so I could refer to it all at once when I work on the system. I have a 75VA transformer on order from the Supply House. Also I retested the 5 other motor operators and you guys were right! Only one other end switch was bad. On the others the motors turned but did no go far enough to close the switch!! Just like some people said. My only excuse was that I had no previous experience using a multimeter when they failed the last time (big difference between knowing theory and actual practice). When the new ones failed recently I didn't even bother to check because I thought I knew what was wrong. Lesson learned.

By the way the China Syndrome is silly nonsense dreamed up by the movie industry to make things more exciting. The truth of the matter is that as soon as the core begins to melt, it loses the geometry that is conducive to fission and will begin to cool down. Even if it didn't, its still not hot enough to get through the reactor wall and many feet of super dense reinforced concrete beneath it.

During the Three Mile Island accident the general public received an additional average dose of 2 millirem (on top of the 600 millirem exposure they got from just being alive that year). Its all a lot of hype and everything that most people think they know (and have been told) about radiation is wrong.

Its more of a political problem than an actual safety hazard. Take the recent Japanese accident. Three people died during the evacuation. The evacuation was strictly political as the levels of contamination in most of the residential areas were not even remotely dangerous.

You can go to the supermarket and buy and eat radioactive material that is many times greater than the contamination levels they had (Nosalt- potassium chloride). Three dead for no good reason!! Ignorance by the public and especially the media is the real hazard at any nuclear power plant (excluding those crazy Russians!).

mcho

Thank you Hot Rod. You talked me into it! I am going to buy these valves the next time one of mine fails.

Thanks again to everybody who has helped. I tried to give you all points but Erin told me all that clicking didn't work because I can only select one accolade. But I did at least that.

GREAT NEWS. I may have stumbled upon a potentially qualified contractor because of this forum. The name is Keefer Radar who owns Outlaw Mechanicals in Albuquerque.

Everything I read about him and on his own blog also, convinced me that there is hope. He was contractor of the month for TACO and Caleffi according to a news article. I may never have to fool with the heating system again!! I am so excited! I just hope he is not too busy to come to Santa Fe!

mcho

All of you that said that it was the transformer were 100% right. So thats what has been killing the valves. After much research I am 99% certain that the secondary transformer is a Honeywell AT72D1683 rated for 40VA. I misread the "D" as an "O" and the "8" as a "9." The numbers were put on in a sloppy manner and they are a little blurred.

Consequently at 7.7 VA power consumption per V8043E1012 the maximum number of valves is 5 just as people said. I have 7. Its no wonder that the fuse kept blowing on the coldest days!!

Just another indicator of the rampant incompetence of the monkeys that installed the system. I would never have known without the help from you guys!

On another note Honeywell says:
Use this valve in closed loop hydronic systems that do not contain dissolved oxygen in system water, such as fresh water from frequent source of makeup water. Valve designed for cycling (not constantly powered on) applications.

Hmmmm. Thats also a requirement for the Entron III tubing I have. No provisions for that are installed. Hopefully the contractor will know what to do about that. I have an air ejector but I doubt it removes the O2 (because its "dissolved").

Canucker

Not sure how far away from Silver City you are, but if you can get Kurt from Sothwest Energy Integrators to look at your system you'll be in good hands. He goes by the screen name @SWEI on the site. Haven't heard from him in awhile though, hopefully he's just been busy

mcho

Unfortunately Silver City is 244 miles from Santa Fe. New Mexico is a giant state. It would be like hiring someone from just past NYC in Pennsylvania to work on a system in Boston.

Canucker

I have relatives with the same problems in the north of our province. A lot of space but not a lot of choice in contractors when you're that far north and no one covers the whole area, it's bigger than Texas

mcho

@Canucker
The Internet has made anything possible. As much as I don't want to spend my time fixing my system, the nice people on this forum have made it possible for an educated home owner to do their own repairs. Plus the Internet makes it possible to buy the parts needed which is sometimes not possible locally.

HomerJSmith

"Consequently at 7.7 VA power consumption per V8043E1012 the maximum number of valves is 5 just as people said. I have 7. Its no wonder that the fuse kept blowing on the coldest days!!"

These two things have nothing in common. Replace the relay on the control board.