Honeywell V8043f zone valve wiring problem

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Old 11-06-10, 07:21 PM
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Honeywell V8043f zone valve wiring problem

I'm trying to wire up 3 Honeywell V8043F zone valves to my Hydrotherm HV - 75 - HSI boiler. The schematic on the boiler shows 2 lowvoltage lines from the controller/xfmr feeding to a T-Stat. But my issue is I have 3 zone valves and 3 T-Stats and need a schematic on how to install them together. I guess what I don't get is the end swith terms on the valves. Are they all just wired together from one valve to the other and thats it? I don't have a burner or circulator circuit that those need to feed after being connected to the valves. From my understanding of the boiler schematic I would be powering the 3 zone valves from the 24V coming from the boiler. I would love to see a diagram somewhere of the 3 zone valves and an internal diagram of the valve itself so I can understand how that works also. The zone valve has 5 terminals, 2 end switch terms, 1 TH/TR term, 1 TH term and 1 TR term. Thanks in advance for any help.
 
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Old 11-06-10, 07:45 PM
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You want to be real careful using the internal transformer in the boiler to run the zone valves. It has a limited amount of current that it can provide and most of that current is needed to operate the gas valve. While it may be possible to do, I personally would not recommend it.

Better to pick up an EXTERNAL 24VAC control transformer such as a Honeywell AT72 40VA or equivalent and use that to power the zone valves.

more later...
 
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Old 11-06-10, 07:53 PM
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Didn't you get an install booklet with the zone valves? This one is for the '5000' series of the V8043 series of that valve... all the details of wiring are the same as your valves.

http://customer.honeywell.com/techli.../95C-10932.pdf

Yes, all of the endswitches would be wired in parallel and would connect to the boiler in place of the thermostat that is shown on the wiring diagram for the boiler.

Again, if you are running 3 valves don't try to use the internal transformer on the boiler. If it ever happens that all 3 valves try to open at one time there won't be enough 'juice' left to operate the gas valve.
 
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Old 11-06-10, 07:59 PM
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A little explanation...

On your valves, the TH/TR terminal is not wired to anything internal to the valve. It is simply provided as a convenient 'tie point' for the wiring.

See figure 7 in that PDF file. Probably the easiest way to wire three valves up would be to 'daisy chain' the wiring from the transformer between all three valves...

one side of external transformer to TR on first valve, on to TR on second valve, on to TR on third valve.

Then, do the same with the TH/TR wiring.

Then, each thermostat wires to the TH/TR and TH terminal of it's respective valve.

Do the same with the ENDSWITCH wiring... From one valve to the next to the next, then the two wires off the the boiler ( the R and G terminals I believe ? if I recall correctly?)
 

Last edited by NJT; 11-06-10 at 10:49 PM. Reason: I didn't remember correctly... so I fixed it...
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Old 11-06-10, 08:27 PM
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This is the type of transformer you want to use:


photo courtesy pexsupply.com

AT72D1683 - Honeywell AT72D1683 - Foot Mounted, Plate Mounted, or Clamp Mounted 120 Vac Transformer w/ 9 in. Lead Wires (40VA)

Mounts on a 4" junction box, power it from the same switched AC line that is powering the boiler system so that it's power goes off when you switch off the boiler.
 

Last edited by NJT; 11-06-10 at 09:58 PM.
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Old 11-06-10, 08:41 PM
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OK, last one for the night... I just looked at the HV install manual and see where your confusion is coming from.

I'm guessing that you are looking at Figure 15, yes?

It appears that Hydrotherm is saying that it is OK to power up to TWO valves from the internal transformer. That diagram is showing a THIRD valve powered from an external transformer.

Since you have three valves, and you need to mount the transformer ANYWAY, the simplest way to wire this is as I pointed out earlier. Use the external transformer to power ALL THREE valves...

Do NOT place the jumper from one of the ENDSWITCH terminals.

DO wire the endswitch terminals to the R and G terminals in the boiler.

Do NOT use the C terminal in the boiler.

I'll throw together a wiring diagram tomorrow for ya...
 
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Old 11-06-10, 09:56 PM
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Here's yer diagram...

Done earlier than I expected...

 
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Old 11-06-10, 10:12 PM
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Now I get it!!

What you posted makes perfect sense and I still have that very same transformer from the previous boiler that was there. I unfortunately wasn't the one that took the old boiler out and didn't get a chance to see how it was wired. It's been many moons since I've installed a boiler. Thank you very much for the timely respons and I will let you know on Monday how it turned out.
 
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Old 11-07-10, 05:36 AM
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Hey NJ Trooper

Did you find that diagram online or did you draw that up yourself? If you did draw that yourself, what program are you using if you don't mind me asking?
 
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Old 11-07-10, 09:48 AM
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I started with the diagram in the boiler manual and modified it. You should notice a very strong similarity! I use PhotoShop...
 
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Old 02-28-13, 06:44 PM
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I am reading your post. Could you tell me what are the two wires coming from the thermostat? Is that red and white? What if I use the same system for cooling? Does yellow get wired into this as well?
 
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Old 02-28-13, 07:26 PM
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Hi turfguy... don't know if you noticed... this thread is like 2 years old... I'm still here, but the original poster ain't...

Typically the wires from a thermostat are red and white, but there's no "rules" that absolutely say so.

If you are wiring a thermostat for heating AND cooling, you need to be very careful that you don't 'backfeed' the transformer in one system from the transformer in the other system. There's very specific wiring that needs to be followed.

There's a better forum for your questions about thermostats:

Thermostatic Controls - DoItYourself.com Community Forums

I think you'll get better answers there...
 
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