I am wiring a Taco ZVC-406 zone valve control panel and am confused in one area: The wiring between the zone control panel (ZVC-406 EXP) and the system pump. From the wiring diagram it looks to me that it is 120VAC, for which I would run 12 gauge romex. However, my concern is that the wiring block on the panel itself is the same kind/size of terminal block as for the 24VAC lines (thermostats, zones valves). Additionally, the panel box "knock out" directly below the connection point is labeled "24VAC". If 24VAC, I will run 18 gauge.

Here is the link for the wiring diagram.

http://www.taco-hvac.com/uploads/Fil...ry/102-108.pdf

So is it 120VAC or 24VAC? I really think it is 120VAC but just need to confirm. Any help much appreciated.

-Scott

 

The pumps run on 120VAC. You don't need to wire the pump to the ZVC. You can leave that on the boiler aquastat, where it probably is already wired. You will run low voltage off the "A" connector, over to the T T terminals on the aquastat. The aquastat will control the pump when TT closes.

If you are connecting a separate pump for an indirect, that will be wired to the panel though... so tell us a bit more exactly what you are wiring.

I wouldn't use 'romex' (or NM) cable on any exposed wiring, instead, use type MC with the metal jacket... formerly known as BX.

 

Trooper,

Thanks for the reply. I apologize because I should have been more thorough in my original post.

This is for a nearly completely new system: modcon boiler, circulators, manifolds, everything except for some existing cast iron radiators. A total of seven zones- 6 new floor radiant zones (8 loops) and 1 zone for the existing cast iron radiators.

I am using two zone valve control panels (a MASTER (6 zone) and SLAVE (4 zone) set-up). The MASTER has 4 thermostats controlling 5 radiant loop zone valves and the 6th zone on the control panel will control the future indirect water heater. The SLAVE has 3 thermostats controlling 3 radiant loops zone valves and 1 cast iron radiator zone valve. Because of the MASTER / SLAVE set-up, and because I am starting with a 'clean slate', I'm thinking it's probably best to run the system pump from the MASTER zone valve control panel.

I'm leaving valved stubouts for an indirect water heater in the future, but right now I have too much life left on my gas water heater to switch at this time.

The zone valve control panels aren't exposed. I have them located at the manifolds inside a protected access panel.

Again, I apologize for the brevity of the original post.

Any additional help much appreciated.

Thanks,
Scott

 

Have you followed the manufacturers hydronic piping arrangement.
Would you care to post your piping layout, as the indirect may need a special setup in the Taco ZVC box.

Who's mod-con did you use ?

Also you can wire 2 zone valves to one zone output on the taco box, I kinda read between the lines and thought you maybe had 2 zone valves for 1 or 2 thermostatic zoned areas and had them on different zone outputs on the ZVC.

 

TOHeating,

Will be following manufacturer's recommended piping arrangement nearly exactly. Only difference is that I will not be using the differential pressure bypass valve as depicted due to using a variable speed delta-T circulator (Taco 008-VDT) as the system pump. Will be installing the Lochinvar KB080 boiler. Here's the link to the installation manual: http://www.lochinvar.com/_linefiles/KB-I-O-15.pdf

The piping layout will be exactly as depicted in Figure 6-6 (single boiler zoned with valves) minus the differential pressure bypass valve.

In the instances where I have two zone valves being controlled by one thermostat, I will wire those zone valves to the same zone output on the ZVC. Sorry for the confusion on that.

Thanks for the help.

-Scott

 

OK,

Great choice on the variable speed delta tee circ. , but don't buy it and go get yourself an ECM circ from Wilo or Grundfos.
Leading edge stuff.

As long as you hydraulicaly seperate the boiler from the system loop, don't use a variable speed circ. on a high restriction heat exchanger (but you know that already).

Wire the thermal motors / electric motors of the zone valves in PARRALLEL and the end switches in series.

Sounds like your on your way.

Good luck.

 

TOHeating,

Can you help me understand your preference for differential pressure circulator (WILO ECO / Grundfos Alpha)over the delta 't' circulator for the system circulator in my set-up? In my mind I'm seeing them both as solving the same problem, just in a different manner. I'm sure I'm missing something.

My setup will use the factory-supplied (constant speed) Grundfos UPS 26-99F for the boiler loop.

I'm tracking on "Wire the thermal motors / electric motors of the zone valves in PARRALLEL and the end switches in series."

I'm looking for confirmation that, given my set-up, I should run 12 gauge (vice 18 gauge) from the ZVC-406EXP MASTER panel (End Switch Pump terminal) to the system pump.

This is all very helpful. Thanks guys.

-Scott

 

Those little pumps probably will never draw more than a few amps at most. They certainly don't require 12ga. I bet you could get by with 16ga... but certainly 14...

Why not run FMC (flexible metal conduit) and pull 14 ga THNN (or 16 ga if local codes allow) ? The stranded wire will be easier to work with (flexibility).

TO, what do you wire pumps up with?

 

ECM motors are just so sweet.
Draw next to nothing in terms of power. The Taco VS pimp is a great circ, and will indeed give you energy savings when it's "dialed down". I like ECM, I think its about time we heating professional's look at the entire system effieciency, not just what the boiler can do.
The 26-99 is a pretty hungry pump, and I would see what i could do to,
A) anaylize the system pipework to ensure it's really required,
b) if I needed to run it, then make sure I run it in the "sweet spot" where it's the most efficient.

14 Guage wire is more than enough for any zone control box.
The ZVC boxes I think are fused at 4 amps on the 24 VAC side.
The ZVC 404 has one 40 VA transformer, and the 406 has 2 40 VA transformers.
The SR series can pull more but are rated at 12-15 amps max. (from what I remember right now).
I wire all near boiler stuff with 14 ga. "BX" unless I have a big motor to control, then it is done thru an external contactor.

 

I agree with all that is said but I have a question. I was told by a codes guy and a very good electrician which seems to know the codes fairly well the NEC states any circuit with a motor requires 12 ga wire.
I know in my area the local code states the only place 14 ga. wire can bu used is between a light switch and the light fixture.

 

TO,

As it pertains to the wire between the ZVC 406EXP and the system pump, is the signal 120VAC or 24VAC? Given the wiring diagram (attached in the original post on page 2 where it shows the system pump wiring), I see it as 120VAC, even though it is physically located on the "other side" of the 24VAC transformers on the panel. This is the issue that's causing me the confusion. I think I am just really slow on the uptake on this one.

As it pertains to using the 26-99 for the boiler loop:

1. My going-in proposition is that I want to reduce my power consumption as much as reasonable while still keeping my warranty in tact. As far as analysis on the pipework recommended for my application in the installation manual, is it worth me calling a tech rep at Lochinvar and asking if there an alternate piping schematic that will eliminate need for the 26-99? Is there additional work I can do on my own to determine this?

2. If required to run the 26-99 in the boiler loop, how do I find the "sweet spot" for efficiency?

Thanks again. You guys are great.

-Scott

 

Scott

RBECK, I have no idea about the US NEC. I am sure you are absolutely right on the money with the wire size. Saying that, I don't know how many installers actually use 12 ga.
Up here some localities like to see a switch at ever motor to isolate it if it requires service. I disagree with this as much as possible. Too many switches on a mechanical panel confuse people and the next thing you know there is a service call. And if it's just installed, then it's usually a free one :-(

 

Very possible! Last time I looked at it, there were some specifics as to the horsepower rating of the motor, and it might still be so. I do know that they recently revised the book, making it even harder to understand than it already was... I'm not even gonna crack open my '78 copy to check!

 

By the way, Scott, the circ motors are on 120VAC... what TO said about the 'endswitch'... that panel has relay contacts on those terminal strips... you can't just run two wires from there to the pump... you run the neutral to the pump directly, the hot goes to one terminal, the other terminal goes to the pump ... just like a light switch on the wall...

 

Good thought. AWG 14 is the lightest gauge wire allowed in most localities for 120-V ckts. In any case, a circuit with #14 conductors anywhere in it must be protected with a 15-A fuse or ckt breaker.

I "used" to be very familiar with the NEC, and recall no requirement that all motors, regardless of size, must be supplied with min #12. However, any conductors supplying a "continuous" load, which could include a circulator, must be derated 20%. So, a #14, normally good for 15A, is only good for 12A if supplying a continuous load. Most residential circulators will draw much less than 12A.
Doug

 

Gents,

Got it. I'm tracking now- and also now understand why the panel came with the little plastic dividers. Makes perfect sense.

Thanks guys.

-Scott