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Posted By: Admin HVAC T-Stat Wire Routing - 05/03/05 02:07 AM
Quote
I often see air conditioner installs that appear to have no t-stat line going to the remote condensing unit. This can be for three reasons:
- it is run within the power conduit (a violation);
- the unit operated on the principle of 'pressure drop,' and needs none; or,
- as shown here, the HVAC guy ran the wires with his 'line set.'

These pics show the need to know a little about other trades, as well as your own.

- renosteinke
[Linked Image]

[Linked Image]
Posted By: Trumpy Re: HVAC T-Stat Wire Routing - 05/05/05 12:16 AM
John,
I used to work for a company here that specialised in installing AirCon/HVAC equipment and the majority of our systems worked off of a Pressure switch.
Running a thermostat wire inside the same conduit as the Mains wiring sounds a little dangerous, considering that the T/Stat wire is often very lightly insulated, to say the least.
Speaking of insulation, were these pictures taken before the HVAC guy had a chance to insulate his pipe-work?.
Often the liquid (smaller) line would go un-insulated here.
I was hooking up the power to a new house recently where the Building Inspector refused to sign-off the Building Completion Notice until there was insulation on the Gas (larger) pipe of the AC system.
Un-insulated pipes like this cause water problems from dripping Condensation. [Linked Image]
Posted By: renosteinke Re: HVAC T-Stat Wire Routing - 05/05/05 01:30 AM
One must start the day early to slip one past Trumpy!

Yes, I took the pic before the insulation was added, so you could see the wire.

NEC does ban running "power limited" circuits in the same raceway as power cables- so running the t-stat wire together with the power leads is a violation. The whole point of my pic is to show your average non-HVAC person that the t-stat wires are often run separate from the power, even though they may not be visible without taking things apart.

Likewise, most electricians are not aware that some systems don't even have a cable run to the condenser (outside unit).
Posted By: Trumpy Re: HVAC T-Stat Wire Routing - 05/05/05 09:10 AM
BTW John,
Who was that idiot that nailed that dwang (Horizontal timber piece) in to hold the T-stat wire, in the top pic?.
Looks like the nail-gun completely missed as did the person fitting the dwang. [Linked Image]
Posted By: renosteinke Re: HVAC T-Stat Wire Routing - 05/06/05 12:44 AM
That fine bit of "carpentry" was done by the HVAC guy.
Posted By: Trumpy Re: HVAC T-Stat Wire Routing - 05/06/05 02:20 AM
The sheet-rockers are going to love that little piece of artistry. [Linked Image]
Posted By: tshea Re: HVAC T-Stat Wire Routing - 05/06/05 05:04 PM
Looks like the stud split, on the right, where Mr. HVAC added his 2x4.
Just proves anybody can be an electrician if they get hte right matchbook cover!
Posted By: HVACInfo Re: HVAC T-Stat Wire Routing - 06/05/11 09:41 AM
Many HVAC Technicians are certified to do some electrical work, it is really part of the trade. If your uncomfortable with the work that was done you can get a second opinion from another HVAC Contractor. You can find some in your area by going to http://www.airconditionerfeatures.com/location/contractorsdir/NY.html
Posted By: harold endean Re: HVAC T-Stat Wire Routing - 06/06/11 02:12 PM
Here in NJ a lot of HVAC people have EC's working for them. A lic. EC will sign all the permits and hopefully do the electric work.
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 06/06/11 03:00 PM
Harold:

Are you tastefully implying something ???

"A lic. EC will sign all the permits and hopefully do the electric"

Posted By: EV607797 Re: HVAC T-Stat Wire Routing - 06/06/11 04:59 PM
I know that this is sort of unrelated, but I am curious to know what the heck that gas stub-out is for. It doesn't make much sense to me unless I'm missing something.
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 06/06/11 06:55 PM
Ed:

Although I did not take the pics within, this is a common rough out for a warm air furnace with an 'A' coil for the AC. Gas is for the heating portion.

Posted By: EV607797 Re: HVAC T-Stat Wire Routing - 06/06/11 07:40 PM
I thought that as well, John. I guess what had me stumped was the block of wood that appeared to have been placed for a thermostat. In all my days, I've never seen a thermostat located so closely to a furnace.
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 06/06/11 09:13 PM
I guess the HVAC guy wanted the t'stat wire right there for some reason.

Posted By: renosteinke Re: HVAC T-Stat Wire Routing - 06/11/11 11:26 PM
I've been delinquent in watching this thread! It took me a moment to realize these were MY pics!

The install is a commercial building. The A/C is only half the picture; the other is the furnace (not yet installed, hence the stub-out.) The t-stat wire needs to go there, because it is the furnace blower that circulates the air past the evaporator coil - which is mounted in the same ductwork the furnace uses.

This is 'kosher' since the t-stat wire simply tells the furnace controls to turn on the blower; it doesn't actually power the blower.

You see two wires because there are to be two units; one to serve the upstairs and one to serve the downstairs. Both heating units are located in the same (second floor) mechanical room.

A little bragging is in order. This job was my first 'design/build' effort. Details were sketchy, and the manner of construction unforgiving. Still, I was able to guess well enough that, in the end, I only needed to relocate two receptacles- and I was able to 'cheat' a bit on those.
Posted By: Alan Belson Re: HVAC T-Stat Wire Routing - 06/29/11 03:41 PM
tshea is right. Blown up, you can see the stud was split. How else would a framing nailer get the heads flush with the stud? 'Someone' then worked over the area with an electric [?] planer to smoothe it over, hence the shavings on the deck. When sheetrocked, there will be a huge shallow dent.
Posted By: gfretwell Re: HVAC T-Stat Wire Routing - 07/06/11 03:57 AM
I know I am late on this but I always see the T stat wire run with the freon line set. The installer tapes the T-stat wire to the outside of the armaflex while he is putting it on the evaporator line. Then they run it all together as an assembly. That also eliminates the problem of the electrical inspector complaining about it being taped to the seal tight.
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 07/06/11 06:52 PM
Tape is not an approved means of support for any cabling! Comments?
Posted By: gfretwell Re: HVAC T-Stat Wire Routing - 07/06/11 10:37 PM
Cite that.
I don't see any listing mark on tywraps or Romex staples either. wink
Posted By: harold endean Re: HVAC T-Stat Wire Routing - 07/18/11 01:34 PM
John,

Yes, I guess you could say I was tastefully stating the fact that all permits signed by an EC, might not ever see a Lic. EC on site. After seeing some of the work done, you just KNOW an EC wasn't there.
Posted By: harold endean Re: HVAC T-Stat Wire Routing - 07/18/11 01:37 PM
Greg,

What about that all important sec of the code? 90.4 which says, you do as I say? smile

A lot of AHJ's hide behind that section a lot.
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 07/18/11 06:18 PM
Harold;

Yes, you were tasteful! I refer to those guys as "paper hangers"!

Amazing, when the EC is called/contactedfor a violation, the responses are really funny. "What job"; "what are you talking about"; "never heard of that person"....etc.

It's even hilarious when no corrections are made, and the EC of record shows up at the counter with the Notice of Violation & monetary penalty in hand!!
Posted By: gfretwell Re: HVAC T-Stat Wire Routing - 07/19/11 04:25 AM
I doubt most electrical inspectors have ever seen an installed A/C condenser on a job site. The EC sets the disconnect, gets his final and that is it. The condenser might drop the day before the customer closes. (along with the appliances)
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 07/19/11 01:27 PM
Greg:
Up here, a 'Final' inspection means just that "Final". All equipment must be installed.

There is no way that I am aware of to check the circuit for the compressor without seeing the nameplate, for minimum circuit ampacity, and max OCP.

Harold & I are talking about replacement HVAC. A Lic EC is required for the compressor up here.

Posted By: gfretwell Re: HVAC T-Stat Wire Routing - 07/19/11 06:40 PM
Florida will allow the HVAC contractor to make up the whip to the disconnect. They usually will not drop the condenser until the last minute because they have a habit of walking away.
The flip side of that is that the disconnect will usually be wired to 310.16 so it really doesn't matter that much how big the condenser is since the wire is plenty big.
Posted By: harold endean Re: HVAC T-Stat Wire Routing - 07/20/11 01:34 PM
Greg,

As John said, on new houses or new HVAC jobs, the outside compressor has to be installed. If the HO wants to move in before the outside unit is ready, my boss will allow them to Co the building, but they have to pull a new permit for the units that weren't installed. This way we can get back into the building to check the HVAC when they are installed.
Posted By: harold endean Re: HVAC T-Stat Wire Routing - 07/20/11 01:40 PM
John,

Just today I see a permit on my desk. It was for an HVAC replacement. I did plan review on 6/24 and noticed that the permit for electric wasn't sealed and was filled in by the HVAC contractor. I called him up and left a message stating that the permit needed to be signed and sealed. So today as I walk into the office, the permit was on my desk. I thought the permit might have been sealed, but to my surprise, I saw a copy of a bill in here that the job was already done and paid for. The best part of this whole story is that the bil was dated 5/24/11. That was almost a month before we even got the permit for plan review. I can't wait to here the story behind this one.
Posted By: HotLine1 Re: HVAC T-Stat Wire Routing - 07/20/11 08:00 PM
Harold:
Before Bill has us arrested for 'jacking' this thread, perhaps either you or I can start a thread on the permitting issues!

Quickly, yuor situation above, I would send the HVAC guy a Notice of Violation, Electrical Subcode & Administrative, for $1000 to get his attention!

edit: I started a thread for permit issues for AHJs and ECs. Lets carry this on there, OK?
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