Good installation details install a zone valve on the return side of the heating piping loop where it will be exposed to lower and thus less stressful temperatures. The motor sits atop and operates a mechanical shaft that, by rotating, opens and closes the zone valve in response to a call for heat from the thermostat. 5 loops of hot water heating piping leaving the boiler (one at each zone valve) Just stopping current to the "ON" position will do nothing as the valve stays open. Indeed when your boiler (hot water heating system or "hydronic heating boiler") is also used to make domestic hot water (for washing and bathing) the boiler will run form time to time to keep its temperature high enough to produce domestic hot water. Thank you. Not for use with oxygenated water, And this is not just an instantaneous short either - once those valves start going, they keep going as long as necessary. Also see Could be a bad circulator, a zone valve not opening, or air in the heating zone piping.
- disconnect andlabel the zone valve wiring connections - with POWER OFF On 2021-01-21 by (mod) When the call for heat stops, the valve closes to stop circulating hot water. or something? Thanks that's a very helpful question. And over time a relief valve that leaks can also clog from mineral deposits and - to put it technically - crud on the valve seat. I dont know if I need to depressurize my system or drain it before I do any of that (or how to do those things, but would love to save my self hundreds to thousands of dollars from doing it myself), @Jon Green, Thanks for pointing out the operation of the WR-1311 Zone Valve Or see ZONE VALVE DIAGNOSTIC FAQs for help with diagnosing zone valve problems. I'm not aware of temperature-tolerance differences among the two valve descriptions you cite, and am confused by the query: in my limited experience a heating zone valve is opened or closed by the room thermostat. If the actual valve is a "paddle valve" type closure the valve may not open and close properly and may flutter, bang, or jam. Integral end-switch It's not clear to me that the added heat from the 40VA transformer wiring that powers this zone valve would normally be sufficient to contribute to the product's failure in the field. My understanding is that the orange is normally intended as a feed to tell the boiler to fire. The Here is another pic of the system, any insight someone could provide on changing my zone valves and the steps I need to do to pull it off would be so appreciated! Dennis: thanks for the follow-up. (Fig. When the thermostat
As I noted, unless the valve mechanism itself is damaged, you can just change the power head - leaving the actual valve assembly in place. Watch out: for conditions that could contribute to zone valve failure.
I should add these details about the different Honeywell V8043 zone valves: Honeywell V8043G - PN 40003916012 normally closed has as an end-switch., contain dissolved oxygen in the system water. Watch out: however, for wiring errors, short circuits, or a misbehaving low voltage transformer. It's a good system but we are trying to improve costs and new procedures develop with time. Reading comments by various HVAC service techs we see an OPINION that "which is better" Honeywell or Taco turns in part on which zone valve model you're installing. Honeywell V8043D - normally OPEN (your valve) PN 4000396014 has NO END SWITCH - the installation presumes that the thermostat or other control is activating the circulator pump. While typical indirect water heaters use a heating loop encompassing a circulator pump and check valve, some systems may use a zone valve in this piping loop that first opens to let hot water flow though the piping loop (boiler to water heater coil and back to boiler), and second, when the valve has opened, it turns on a circulator pump to cause water movement. The installer surely had a reason for the "normally-open" approach. @Anonymous, When pipes make noise, does that mean PLUMBING NOISE TYPE CHECKLIST
The room temperature is 22 C and yet the thermostat is down all the way. It pays to read the specs. Heating water piping in a building, particularly where hot water baseboard heat is used, may be divided into separate heating zones (different floors, or different areas on a single floor) to For other readers, the installation instructions and wiring diagrams for this zone valve are at
like 25psi? holding circuit stopping the valve in the closed position. switch makes with the holding contacts. You'll find articles on all of those in the article index. hydronic systems. dissolved oxygen, which is found in systems that have a The zone valve (Honeywell) which feeds the upstairs kitchen/dining/living/bath (large area) is making noise, overheating, and not opening when the thermostat calls for it to. I use the word "register" to refer to a warm air outlet - a furnace heating system - is your heat a water-to-air heating system? If the zone valve failure is in the actuator motor, that's a pretty easy repair as the cover can be removed, the motor removed, and a replacement installed without having to do any plumbing work. Reader should make sure they have at least a 75VA transformer for the valves - 60VA for full load plus 20% headroom. what is the hot water pressure for heating system normally? I have 3 separate zone valves in my home. Do i have flow issue. A typical design will include a thermostat on the water heater that will cause hot water from a physically separate heating boiler to circulate through the heating coil located in the bottom of the indirect-fired water heater. so all good. - zone valve opens but boiler doesn't turn fire up. The water temperature inside the indirect fired water heater tank is sensed by a thermostatic control that causes the hot water tank's contents to be re-heated as needed, typically by turning on a circulator pump that moves hot water from the separate heating boiler through the coil in the bottom of the water heater. @Anonymous, In order to change out a White Rogers Spin on or Twist On Zone Valve do you have to turn off the water or can you simply take off and twist on the new one? I have a zone valve dripping and when the thermostat turns on the zone valve spins and won't stop on open. Use this valve in hydronic systems which DO NOT We welcome your further photos, comments, questions. Otherwise the thermostat will need replacement. But IF there is heat coming out of your radiators and baseboards long after the thermostat has stopped calling for heat, then see I've seen more Honeywell than Taco zone valves installed, but I have no actual zone valve failure rate data that demonstrates one BRAND is "better" than the other. begins to open the valve. First let's get heat back: for those two zone valves: try putting the valve in the MANUAL OPEN position to see if that restores heat; that'll be diagnostic. Thanks for a helpful "sticking" zone valve repair question. - Daniel, What I understand is with the normally open valve power is required continuously keep the valve closed. We live in a area with long cold winters. When a zone valve is dripping from the solder or sweat connections it may be possible to repair it - but that'll usually require draining water out of the zone piping first. Zone valves on hot water heating systems: How do I choose & install a zone valve, how do I wire up a zone valve, and how do I troubleshoot, repair or replace a zone valve? I have used, installed, and repaired both brands of zone valves since the 1970s; In the northeastern U.S. As the How do you check a zone valve to see if it is working? I have a boiler in an extension that provides hot water to the kitchen and extension. LOW VOLTAGE TRANSFORMER TEST I don't like leaving it like that, so I put it there at night when the house gets cold, put it back to normal during the day. Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. On 2022-03-10 by Inspectapedia Com Moderator - Taco wiring guide. Steven: A of motor switch makes with contact 4 then breaks the 1. responds to a thermostat's call for heat (Completing a circuit through contact 6 and the thermostat anticipator.) The one problem zone valve opens when I adjust the thermostat but the hot water only flows to the valve and a little beyond then the line starts cooling down and I have no heat in that area. The contact arrangement is constructed so that when the shaft (Search InspectApedia.com for AIR-BOUND HEATING SYSTEMS to see how we get the air out completely) is it the actuator or could it be air-block? If that's the problem you'll want to replace the zone valve head. 5 individual room thermostats. This seems to have stopped working as the radiators were cold even with the Thermostatic Valves fully open. can be replaced without removing valve body from line. But yeah, there can indeed be a "left-over" control from discontinued equipment or devices. However if you are going to the trouble of rearranging or re-sweating zone valves at a hot water heating boiler, I'd see if it were possible to put the valves on the return side of the boiler - cooler water temperatures there may improve zone valve life. Take a look at the wiring guides at You'll save significantly just by dropping the thermostat set temperature. Bottom line: Both Honeywell and Taco make reliable zone valves. When changing the thermostat, there are some models that can be wired to operate either type of zone valve: normally closed or normally open. The hot water and CH (central heating) in the original house are provided via a 22mm feed from the boiler via a Dunsley Nutraliser to the house radiators and bathroom hot water. InspectAPedia tolerates no conflicts of interest. The thermostat is at the lowest setting but our oil in floor heating system still fires up here and there (we dont want the oil in floor on since we have electric heat pumps running). makes with holding contact providing a holding circuit. @Jason, Thanks Dennis, indeed you are perfectly correct: the HONEYWELL V8043D zone valve [PDF installation instructions] is a "normally open" valve while the Honeywell V8043C, F, or G models are "normally closed". Please find your question and my detailed reply now at the Reader Q&A section near the bottom of the article above on this page. Stuck Zone Valves: Older models of some zone valvessuch as these Flair valves are perhaps more likely to be "stuck" either open (you'll have heat in that zone) or shut (that zone won't heat). Why would anyone want a valve like that, instead of a spring or mechanism that just turns the valve automatically to the off position when the thermostat turns off? They seem to always be very warm/hot. So that's normal. Usually people don't go to the trouble of installing a valve or control unless it was needed. Andre said: Have a boiler with three zones, two for upstairs, one downstairs. hydronic systems. I got zone valves, Honeywell thermostats, Onrom relays, and a Taco pump Why is it taking so long as much as 30 minutes, On 2022-01-09 by Inspectapedia Com Moderator - different pipe noises mean different things. @Gene Lair, Are there some special heating needs or applications? The temperatures of the circulating hot water are, in my OPINION more likely to be a factor in zone valve life. and the You may need to clear or refresh your browser cache to see the updated page. What is the point of this valve in the extension radiator loop as it just seems to get a signal to open from the controller, take a few seconds to open and then stay open until the programmer switches it off and the spring closes it? [The Honeywell Honeywell V8043 series zone valve is ] suitable for glycol/water mix up to 50:50 use in closed
of the motor revolves 90 a new set of stationary contacts makes The heating system installer or service technician addresses this heat imbalance by fine-tuning the volume or the rate at which heating water is delivered to different building areas. See CHECK VALVES, HEATING SYSTEM for details. at WATER HAMMER NOISE DIAGNOSE & CURE, can occur in both building potable water supply systems (sinks, tubs, showers) and also in hot water heating systems as well as at water heaters or calorifiers. The control of heating water through these different heating zones may be accomplished On 2021-11-22 TACO ZONE CONTROLS WIRING GUIDE I have a four zone one circulator pump hot water system. If not then I suspect the zone valve end switch isn't working. She or he does this by installing and adjusting manual or automatic zone balancing valves or zone flow control valves of various types. Could my circulator pump be bad although the other three zones are working? Thanks for all of the information it will help us in making a decision. It is possible to simply change the actuator heads from the D model to one of the other models - changing wiring and thermostats as appropriate, leaving the actual valve body installed. through the zone. When boiler is on, and pipes hot, the zone valve is very hot, and much hotter than the other taco valve on the system. A slow-closing type zone valve may cause banging heating pipes if installed backwards. I'm unclear what kind of heat we are discussing. Would it be better to have normally closed valves instead of the normally open ones? also see ZONE VALVE MANUALS & WIRING. If I disconnect the wiring and leave the zone valve open will it only pump water thru that zone when another zone is open and making the pump run? thx, if I gently push on the valve the humming changes. See AIR BLEED VALVE INSTALLATION keep us posted. We have a hot water boiler with 7 normally open Honeywell zone valves. For that work, the job probably goes faster and easier when done by a trained heating service tech or plumber who is familiar with zone valve replacement. - Dennis. Your advice would be appreciated. Honeywell V8043C - PN 40003916011 normally closed, also has no end-switch. Should I move the switch from auto to manual on the zone valve. by Trevor - how to replace Sparco PowerTrack zone actuators broken into pieces. (open the boiler drain, using a hose to direct water to a safe drain location) - drain off pressure and water from the lines enough that the piping in the area of work is empty (so it can be soldered) Use the on Page search box to look for our article series. plumbingsupply.com sells replacement Sparco PowerTrack zone actuators from Honeywell. Indirect fired hot water heaters, in some designs, use a heating coil located in the bottom of the hot water tank to heat the domestic hot water (used for washing and bathing). I want to replace them with more modern zone valves (was thinking the Honeywell 3/4 Sweat valves). Just curious about the query whose 7 zone valves keep failing once a year. dissolved oxygen, which is found in systems that have a WHITE RODGERS 1311 ZONE VALVE INSTRUCTIONS [PDF], On 2021-05-18 by Jon Green - two wire thermostat vs White Rogers 1311-102 Zone-A-Flow valves. -, I turned my thermostat right off and the valve cooled slightly to warm to touch but still makes humming sound - If the zones do NOT heat any rooms with plumbing you may be ok. breaks the holding contact. Also, can the zones valves be installed on the return side of the boiler instead of the supply side? On 2020-11-04 - by (mod) - How do we know that a zone valve is working? Three out of the four zones are working correctly. And about using a normally-open vs normally-closed zone valve: it depends on the application; for example some hot water applications require the valve to be normally open. the valve in the open position when side A of motor switch Since we have no idea what type of noise you're hearing, please first look at this article Zone valves and Taco circulator pumps are, most-basically, associated with hot water heat delivered through radiators or baseboards or convectors. Typically the zone motor or actuator, (properly, the "zone motor assembly") including the White Rodgers models can be removed without interfering with piping (open-close) control of supply water for baseboard radiation, It's safer to refer to the F model but I found it listed both ways. I have no experience with boiler systems but no how to sweat and do copper plumbing. The photo above shows a bank of six zone valves controlling heat distribution in a large home. Zone valves have no trouble operating in that pressure range. Just after the valve starts to close, side A of motor switch Where can I find a schematic of the main board of a Taco ZVC406 6 zone valve control??
- disconnect andlabel the zone valve wiring connections - with POWER OFF On 2021-01-21 by (mod) When the call for heat stops, the valve closes to stop circulating hot water. or something? Thanks that's a very helpful question. And over time a relief valve that leaks can also clog from mineral deposits and - to put it technically - crud on the valve seat. I dont know if I need to depressurize my system or drain it before I do any of that (or how to do those things, but would love to save my self hundreds to thousands of dollars from doing it myself), @Jon Green, Thanks for pointing out the operation of the WR-1311 Zone Valve Or see ZONE VALVE DIAGNOSTIC FAQs for help with diagnosing zone valve problems. I'm not aware of temperature-tolerance differences among the two valve descriptions you cite, and am confused by the query: in my limited experience a heating zone valve is opened or closed by the room thermostat. If the actual valve is a "paddle valve" type closure the valve may not open and close properly and may flutter, bang, or jam. Integral end-switch It's not clear to me that the added heat from the 40VA transformer wiring that powers this zone valve would normally be sufficient to contribute to the product's failure in the field. My understanding is that the orange is normally intended as a feed to tell the boiler to fire. The Here is another pic of the system, any insight someone could provide on changing my zone valves and the steps I need to do to pull it off would be so appreciated! Dennis: thanks for the follow-up. (Fig. When the thermostat
As I noted, unless the valve mechanism itself is damaged, you can just change the power head - leaving the actual valve assembly in place. Watch out: for conditions that could contribute to zone valve failure.
I should add these details about the different Honeywell V8043 zone valves: Honeywell V8043G - PN 40003916012 normally closed has as an end-switch., contain dissolved oxygen in the system water. Watch out: however, for wiring errors, short circuits, or a misbehaving low voltage transformer. It's a good system but we are trying to improve costs and new procedures develop with time. Reading comments by various HVAC service techs we see an OPINION that "which is better" Honeywell or Taco turns in part on which zone valve model you're installing. Honeywell V8043D - normally OPEN (your valve) PN 4000396014 has NO END SWITCH - the installation presumes that the thermostat or other control is activating the circulator pump. While typical indirect water heaters use a heating loop encompassing a circulator pump and check valve, some systems may use a zone valve in this piping loop that first opens to let hot water flow though the piping loop (boiler to water heater coil and back to boiler), and second, when the valve has opened, it turns on a circulator pump to cause water movement. The installer surely had a reason for the "normally-open" approach. @Anonymous, When pipes make noise, does that mean PLUMBING NOISE TYPE CHECKLIST
The room temperature is 22 C and yet the thermostat is down all the way. It pays to read the specs. Heating water piping in a building, particularly where hot water baseboard heat is used, may be divided into separate heating zones (different floors, or different areas on a single floor) to For other readers, the installation instructions and wiring diagrams for this zone valve are at
like 25psi? holding circuit stopping the valve in the closed position. switch makes with the holding contacts. You'll find articles on all of those in the article index. hydronic systems. dissolved oxygen, which is found in systems that have a The zone valve (Honeywell) which feeds the upstairs kitchen/dining/living/bath (large area) is making noise, overheating, and not opening when the thermostat calls for it to. I use the word "register" to refer to a warm air outlet - a furnace heating system - is your heat a water-to-air heating system? If the zone valve failure is in the actuator motor, that's a pretty easy repair as the cover can be removed, the motor removed, and a replacement installed without having to do any plumbing work. Reader should make sure they have at least a 75VA transformer for the valves - 60VA for full load plus 20% headroom. what is the hot water pressure for heating system normally? I have 3 separate zone valves in my home. Do i have flow issue. A typical design will include a thermostat on the water heater that will cause hot water from a physically separate heating boiler to circulate through the heating coil located in the bottom of the indirect-fired water heater. so all good. - zone valve opens but boiler doesn't turn fire up. The water temperature inside the indirect fired water heater tank is sensed by a thermostatic control that causes the hot water tank's contents to be re-heated as needed, typically by turning on a circulator pump that moves hot water from the separate heating boiler through the coil in the bottom of the water heater. @Anonymous, In order to change out a White Rogers Spin on or Twist On Zone Valve do you have to turn off the water or can you simply take off and twist on the new one? I have a zone valve dripping and when the thermostat turns on the zone valve spins and won't stop on open. Use this valve in hydronic systems which DO NOT We welcome your further photos, comments, questions. Otherwise the thermostat will need replacement. But IF there is heat coming out of your radiators and baseboards long after the thermostat has stopped calling for heat, then see I've seen more Honeywell than Taco zone valves installed, but I have no actual zone valve failure rate data that demonstrates one BRAND is "better" than the other. begins to open the valve. First let's get heat back: for those two zone valves: try putting the valve in the MANUAL OPEN position to see if that restores heat; that'll be diagnostic. Thanks for a helpful "sticking" zone valve repair question. - Daniel, What I understand is with the normally open valve power is required continuously keep the valve closed. We live in a area with long cold winters. When a zone valve is dripping from the solder or sweat connections it may be possible to repair it - but that'll usually require draining water out of the zone piping first. Zone valves on hot water heating systems: How do I choose & install a zone valve, how do I wire up a zone valve, and how do I troubleshoot, repair or replace a zone valve? I have used, installed, and repaired both brands of zone valves since the 1970s; In the northeastern U.S. As the How do you check a zone valve to see if it is working? I have a boiler in an extension that provides hot water to the kitchen and extension. LOW VOLTAGE TRANSFORMER TEST I don't like leaving it like that, so I put it there at night when the house gets cold, put it back to normal during the day. Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. On 2022-03-10 by Inspectapedia Com Moderator - Taco wiring guide. Steven: A of motor switch makes with contact 4 then breaks the 1. responds to a thermostat's call for heat (Completing a circuit through contact 6 and the thermostat anticipator.) The one problem zone valve opens when I adjust the thermostat but the hot water only flows to the valve and a little beyond then the line starts cooling down and I have no heat in that area. The contact arrangement is constructed so that when the shaft (Search InspectApedia.com for AIR-BOUND HEATING SYSTEMS to see how we get the air out completely) is it the actuator or could it be air-block? If that's the problem you'll want to replace the zone valve head. 5 individual room thermostats. This seems to have stopped working as the radiators were cold even with the Thermostatic Valves fully open. can be replaced without removing valve body from line. But yeah, there can indeed be a "left-over" control from discontinued equipment or devices. However if you are going to the trouble of rearranging or re-sweating zone valves at a hot water heating boiler, I'd see if it were possible to put the valves on the return side of the boiler - cooler water temperatures there may improve zone valve life. Take a look at the wiring guides at You'll save significantly just by dropping the thermostat set temperature. Bottom line: Both Honeywell and Taco make reliable zone valves. When changing the thermostat, there are some models that can be wired to operate either type of zone valve: normally closed or normally open. The hot water and CH (central heating) in the original house are provided via a 22mm feed from the boiler via a Dunsley Nutraliser to the house radiators and bathroom hot water. InspectAPedia tolerates no conflicts of interest. The thermostat is at the lowest setting but our oil in floor heating system still fires up here and there (we dont want the oil in floor on since we have electric heat pumps running). makes with holding contact providing a holding circuit. @Jason, Thanks Dennis, indeed you are perfectly correct: the HONEYWELL V8043D zone valve [PDF installation instructions] is a "normally open" valve while the Honeywell V8043C, F, or G models are "normally closed". Please find your question and my detailed reply now at the Reader Q&A section near the bottom of the article above on this page. Stuck Zone Valves: Older models of some zone valvessuch as these Flair valves are perhaps more likely to be "stuck" either open (you'll have heat in that zone) or shut (that zone won't heat). Why would anyone want a valve like that, instead of a spring or mechanism that just turns the valve automatically to the off position when the thermostat turns off? They seem to always be very warm/hot. So that's normal. Usually people don't go to the trouble of installing a valve or control unless it was needed. Andre said: Have a boiler with three zones, two for upstairs, one downstairs. hydronic systems. I got zone valves, Honeywell thermostats, Onrom relays, and a Taco pump Why is it taking so long as much as 30 minutes, On 2022-01-09 by Inspectapedia Com Moderator - different pipe noises mean different things. @Gene Lair, Are there some special heating needs or applications? The temperatures of the circulating hot water are, in my OPINION more likely to be a factor in zone valve life. and the You may need to clear or refresh your browser cache to see the updated page. What is the point of this valve in the extension radiator loop as it just seems to get a signal to open from the controller, take a few seconds to open and then stay open until the programmer switches it off and the spring closes it? [The Honeywell Honeywell V8043 series zone valve is ] suitable for glycol/water mix up to 50:50 use in closed
of the motor revolves 90 a new set of stationary contacts makes The heating system installer or service technician addresses this heat imbalance by fine-tuning the volume or the rate at which heating water is delivered to different building areas. See CHECK VALVES, HEATING SYSTEM for details. at WATER HAMMER NOISE DIAGNOSE & CURE, can occur in both building potable water supply systems (sinks, tubs, showers) and also in hot water heating systems as well as at water heaters or calorifiers. The control of heating water through these different heating zones may be accomplished On 2021-11-22 TACO ZONE CONTROLS WIRING GUIDE I have a four zone one circulator pump hot water system. If not then I suspect the zone valve end switch isn't working. She or he does this by installing and adjusting manual or automatic zone balancing valves or zone flow control valves of various types. Could my circulator pump be bad although the other three zones are working? Thanks for all of the information it will help us in making a decision. It is possible to simply change the actuator heads from the D model to one of the other models - changing wiring and thermostats as appropriate, leaving the actual valve body installed. through the zone. When boiler is on, and pipes hot, the zone valve is very hot, and much hotter than the other taco valve on the system. A slow-closing type zone valve may cause banging heating pipes if installed backwards. I'm unclear what kind of heat we are discussing. Would it be better to have normally closed valves instead of the normally open ones? also see ZONE VALVE MANUALS & WIRING. If I disconnect the wiring and leave the zone valve open will it only pump water thru that zone when another zone is open and making the pump run? thx, if I gently push on the valve the humming changes. See AIR BLEED VALVE INSTALLATION keep us posted. We have a hot water boiler with 7 normally open Honeywell zone valves. For that work, the job probably goes faster and easier when done by a trained heating service tech or plumber who is familiar with zone valve replacement. - Dennis. Your advice would be appreciated. Honeywell V8043C - PN 40003916011 normally closed, also has no end-switch. Should I move the switch from auto to manual on the zone valve. by Trevor - how to replace Sparco PowerTrack zone actuators broken into pieces. (open the boiler drain, using a hose to direct water to a safe drain location) - drain off pressure and water from the lines enough that the piping in the area of work is empty (so it can be soldered) Use the on Page search box to look for our article series. plumbingsupply.com sells replacement Sparco PowerTrack zone actuators from Honeywell. Indirect fired hot water heaters, in some designs, use a heating coil located in the bottom of the hot water tank to heat the domestic hot water (used for washing and bathing). I want to replace them with more modern zone valves (was thinking the Honeywell 3/4 Sweat valves). Just curious about the query whose 7 zone valves keep failing once a year. dissolved oxygen, which is found in systems that have a WHITE RODGERS 1311 ZONE VALVE INSTRUCTIONS [PDF], On 2021-05-18 by Jon Green - two wire thermostat vs White Rogers 1311-102 Zone-A-Flow valves. -, I turned my thermostat right off and the valve cooled slightly to warm to touch but still makes humming sound - If the zones do NOT heat any rooms with plumbing you may be ok. breaks the holding contact. Also, can the zones valves be installed on the return side of the boiler instead of the supply side? On 2020-11-04 - by (mod) - How do we know that a zone valve is working? Three out of the four zones are working correctly. And about using a normally-open vs normally-closed zone valve: it depends on the application; for example some hot water applications require the valve to be normally open. the valve in the open position when side A of motor switch Since we have no idea what type of noise you're hearing, please first look at this article Zone valves and Taco circulator pumps are, most-basically, associated with hot water heat delivered through radiators or baseboards or convectors. Typically the zone motor or actuator, (properly, the "zone motor assembly") including the White Rodgers models can be removed without interfering with piping (open-close) control of supply water for baseboard radiation, It's safer to refer to the F model but I found it listed both ways. I have no experience with boiler systems but no how to sweat and do copper plumbing. The photo above shows a bank of six zone valves controlling heat distribution in a large home. Zone valves have no trouble operating in that pressure range. Just after the valve starts to close, side A of motor switch Where can I find a schematic of the main board of a Taco ZVC406 6 zone valve control??