You need to be sure that you are replacing the proper zone valve to ensure that the time you are investing is well spent. In order to do this, you need to adjust every thermostat within your home and set it to a high temperature, so that all the zones will have heat being transferred to them.
Back in the boiler room, you will find that the zones all have levers on them. If you do not do this step, you will find that you not only create a rather large mess, but also you will have caused severe burns to your skin as the water will be incredibly hot.
If you do it wrong you will be forcing yourself to spend a large of amount of money to fix this mistake. This article series answers most questions about Heating System Boiler Controls on central heating systems to aid in troubleshooting, inspection, diagnosis, and repairs.
The photo above shows a bank of six zone valves controlling heat distribution in a large home. We also provide a MASTER INDEX to this topic, or toucan try the page top or bottom SEARCH BOX as a quick way to find information you need.
Our photo at left shows a Honeywell ™ zone valve installation. When the thermostat calls for heat in a particular building area, the thermostat switch causes the zone valve to open, to permit hot water to flow through that zone.
In all cases, when the zone valve is fully open, an “end switch” inside the valve tells the heating system's circulatory to begin operating, causing hot water to flow through the zone. Typically, heating systems using zone valves will have two or more zone valves (usually but not always located close to the heating boiler) and a single circulatory pump (usually located on the return end of the hot water piping close to the heating boiler).
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. Provided the wiring and thermostat are correct and operating, if no hot water flows past the valve on a call for heat (feel the pipes for heat) it may be jammed and need replacement Our photo (left) shows the manual control valve in its “automatic” or normal position on a Honeywell™ heating zone control valve.
See ZONE VALVE BANGING or BACKWARDS Water hammer, discussed in general Stuck Univalves : Older models of some zone valves such as this 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).
If it's a standard 40VA like you find on a lot of equipment from the factory, 7 of those valves will try to draw 60VA if they all open at once. The voltage will sag, the current will go through the roof, and you'll burn the windings on those tiny synchronous motors.
A clogged relief valve means that the heating equipment is unsafe to operate, risking a BREVE. Good practice locates the zone controls and circulatory on the return side of the hydroponic heating loop.
There's theory that the slightly lower temperatures give longer component life and that this location will reduce water hammer noise in the heating zones. If you continue to have annoying water hammer banging when the circulatory pump starts (or stops) consider changing out your zone valves to a slow closing valve such as the Taco #570.
Reply: problems caused by zone valves installed backwards include banging pipes and reduced valve life A slow-closing type zone valve may cause banging heating pipes if installed backwards. Honeywell, for example, says the zone valve “... must be installed so that the arrow stamped on the body corresponds to the flow direction “.
The instructions don't say why but from my reading and field experience I warn that if you hook up a heating zone valve backwards, depending on several other variables including zone valve brand and model and type as well as water velocity there may be trouble: I figure that the manufacturer wouldn't have put parts (springs) in the valve if they were not needed.
(Our Honeywell zone valve photo above shows this mechanical lever. Faulty zone valve wiring connections or thermostatic control.
Watch out : different brands of zone valves may require different wiring hook-ups and a mix of zone valve brands can lead to some head-scratching in figuring out proper wiring. I can 't give a general solution to this problem as we need to look at the wiring diagram.
No electrical power to the zone valve unit or to the thermostat that controls it Air-bound hydroponic heating system : if the zone valve appears to operate properly but heat never arrives in the zone it controls, check that the system circulatory pump is working (pump motor hums & moves, pipes get hot on both sides of the circulatory inlet and outlet). While going through the detailed sequence in the operation of the heating boiler, watch for and inspect the condition of the heating boiler controls and safety devices (as required by ASH 9.1. A.3 automatic safety controls).
Watch out: for boiler water chemical conditions that could contribute to zone valve failure. The dissolved oxygen, which is found in systems that have a frequent source of make-up water, causes the rubber plug inside the valve to deteriorate and eventually fail.
Details on the risks of damage or component failure from dissolved oxygen in heating system water as well as suggestion on avoiding those hassles are now found While typical indirect water heaters use a heating loop encompassing a circulatory 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 circulatory pump to cause water movement.
We have a hot water boiler with 7 normally open Honeywell zone valves. 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.
In the normally closed valve the valve remains closed by spring pressure and opens when the thermostat apples power to it, allowing fluid flow. Reply: Thanks Dennis, indeed you are perfectly correct: the HONEYWELL V8043D zone valve is a “normally open” valve while the Honeywell V8043C, F, or G models are “normally closed”.
The V8043 Motorized Zone Valve provides two-position (open-close) control of supply water for baseboard radiation, convectors, fan-coil units, etc. Quick Fit actuator provides easy snap on and off connection to the valve assembly.
It's a good system, but we are trying to improve costs and new procedures develop with time. Reply: dissolved oxygen in heating boiler water can cause zone valve failure Dennis: thanks for the follow-up.
Easy servicing because the entire power head assembly can be replaced without removing valve body from line. Optional accessory fittings can be provided to facilitate convenient removal of the entire zone valve unit.
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. The temperatures of the circulating hot water are, in my OPINION more likely to be a factor in zone valve life.
The dissolved oxygen, which is found in systems that have a frequent source of make-up water, causes the rubber plug inside the valve to deteriorate and eventually fail. Watch out: however, for wiring errors, short circuits, or a misbehaving low voltage transformer.
Those defects could contribute to zone valve failure, as might corrosive or mineral-laden water in more rare cases. I have a Burnham v8h boiler system I removed the analog thermostats and replaced them with programmable Honeywell stats now the zone valves turn on at the correct temperature but do not turn off.
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. 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.
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. 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'm had 30 years of maintenance experience changing pumps, motors, valves, piping systems, etc., though it is mostly heavy industrial. Thank you for a helpful question on the reliability or quality of Taco vs Honeywell zone valves and actuators.
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. 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.
“Complaints” are anecdotal reports, not peer-reviewed expert research on failure rates. It's likely that both Taco and Honeywell have failure data for their products based on their own research, on field reports, or both.
Bottom line: Both Honeywell and Taco make reliable zone valves. But a humming sound may mean that the valve's motor is jamming (needs replacement) OR that a nearby low voltage transformer is humming and will need replacement soon.
Zone valves are pretty generic and interchangeable, with the caveat that you have to look carefully at the wiring connections to get that right. Here's a Sharking 3/4” copper connector that sports male NP Ton one end.
You'll need to use either a coupling (shown below) or a Sharking connector that provided a male NOT fitting on one end Below is a photo showing typical Shark bite connectors, in this case where I was hooking up a Bosch tankless water heater to a control valve and a service drain.
This weekend temperatures dropped to the lower 30 again and the Zone 2 quit working. The worst of all possible outcomes, as there is no way to run a new wire without opening walls on 1 and 2 floors.
Unless there is some kind of device that I can hook up to Ocoee and downstairs that will communicate to each other(maybe something could be built using 2 raspberry pi). Changing the zone valve head is a good diagnostic step to rule out.
I also checked the 28V transformer although I knew it cannot be the issues as it supplies power to both zones. My guess is that Rh or W1 wires are damaged somewhere inside walls and when it gets colder at night they lose the contact.
The cause of power drop could be deliberate: a timer or economizer, or a poor connection or control board (perhaps affected by temperature variations). That condition means that hot water can 't circulate from the boiler through the zone and that in turn would mean the boiler is seeing the call for heat, turning on, heating up but then reaching its HI LIMIT and shutting off.
I have 2 zones(2 normally closed Schneider zone valves) water boiler and 2 AHU(basement and attic). Zone 2 heat works perfectly fine during the day, I checked the Rh and W1 wires with voltmeter, get 28V reading.
Something that I cannot explain happens at 10PM, The Rh and W1 wires reading is 0, when I call for heat the zone valve does not respond. When during a night I use the manual ON lever on the valve the boiler kicks in and works just fine.
In that circumstance you'll reduce your heating cost and increase comfort by having working zone control. My serviceman has ordered new zone valves but without them, my boiler is heating my house just fine in 18 degrees below zero.
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