Help with change from manual 24 hr timer to digital version?

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RichardinVA

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:? I need to verify that the digital timer a client wants installed can replace the manual timer currently in-place.

The in-place timer is no longer working. The dial has been stripped and no longer functions correctly.

Here are the specs on the "in-place" Manual 24-hour Time Switch "with skip a day" function.
Mfg. Tork Model 7300 3PST Contact Ratings: 40AMP 120-277VAC; 20AMP Inductive 120-277VAC Single Phase; 40AMP Tungsten 120VAC 1000VA (120-277) Pilot Duty 2HP 120VAC;5HP 240VAC, Timing Motor 120VAC 60Hx, Power consumption 3 Watts Max.

The manual switch is described also as a 3PST (3PoleSingleThrow)... Here is the link to the wiring diagram for the Tork 7300 Manual Timer:http://waterheatertimer.org/pdf/7300INSTALLOP.pdf

OK now... Here is what we are told is the replacement in a digital Tork 24 Hour Timer: Mfg. Tork Model DG100A.

The Digital Timer calls for a 120VAC timer supply then has the abbreviation DPDT (DoublePoleDoubleThrow)

See the info and wiring diagram for the DG100A Digital Timer from Tork here:http://www.torksales.com/pdf/DG100_Series_Cut_Sheet.pdf (lower left diagram)

One of my questions concerns this: The Tork 7300 Manual Timer is a 3PST, while the DG100A is a DPDT.

It seems to me that the Manual Timer can feed three (3) loads. While it appears the Digital timer can only feed 2 loads. ???Additionally....

OK.. This is what is currently "in-place" to operate the exterior parking lights operating at 120/208 Voltage.

In the electrical room, from a J-box marked 120V, there are 3 wires entering the manual switch from the bottom of the enclosure via a steel [FONT=inherit !important][FONT=inherit !important]conduit[/FONT][/FONT]. There is a blue, a white, and a yellow. These are all attached on what is called the "front" row. (see the diagram for Model 7300) link above).

The Blue wire goes to pin #1 (see the diagram for Model 7300) linked in previous post above).

The White wire goes to pin #X (I assume it is neutral wire) of 120VAC

The Yellow wire goes to pin #2 (not sure of this yellow wire's function - except it is "hot" when timer is in "On" position)

Now... coming from a J-box marked 208Volt there are 4 wires: a Blue, a White, a Yellow and a Black. These (4) 208V wires also enter the manual timer from the bottom via steel conduit.

The Blue wire, goes to pin #3 in the "middle" row.
(see the diagram for Model 7300) linked in previous post above).

The White wire goes to pin #4 on the "middle" row.

The Black wire goes to pin #5 on the "rear" row.

The Yellow wire goes to pin#6 on the "rear' row.

Note: on the [FONT=inherit !important][FONT=inherit !important]manual [/FONT][FONT=inherit !important]switch[/FONT][/FONT] (Tork 7300), a Blue Jumper Wire is used and connects "L" and Pin #1 on the "Front" row. (See diagram of Tork 7300). http://waterheatertimer.org/pdf/7300INSTALLOP.pdfThe 7300 has a small Motor which turns the day/hour dial. I assume the 120V circuit operates the small motor which is designated with a big "M" on the diagram of the 7300 model.

These are the 7 wires that enter the manual switch via two conduits (one which is clearly marked 120VAC and the other marked 208V). Like stated, 3 wires are 120V (blue, white, yellow) 4 wires are 208V (blue, white, yellow, and black)

As to the number of loads - I am thinking there are: two-208V and one-120V?

Big question is can the digital replace the manual here or not? I do not want to burn it up by wiring it incorrectly!

Please look at both the wiring schematics I have linked to here. Thanks!

Any help is greatly appreciated.

 
Welcome to the forum. :hug:

While you have provided a quite comprehensive description of the existing timer connections, I (we?) cannot answer your question without knowing where the other ends of the wires connect and the load being switched. It appears to be switching three circuits, but it could only be switching two circuits.

That said, even if the new digital timer is incapable, your can make it capable by adding an interposing relay.
 
Loads

Loads

Smart $ said:
Welcome to the forum. :hug:

While you have provided a quite comprehensive description of the existing timer connections, I (we?) cannot answer your question without knowing where the other ends of the wires connect and the load being switched. It appears to be switching three circuits, but it could only be switching two circuits.

That said, even if the new digital timer is incapable, your can make it capable by adding an interposing relay.
Click to expand...

I (we believe) there are (2) lighting circuits 208V controlled by the existing manual style 24-hr/7day timer. This will need to be verified on Monday when we return to the site.

Additionally there appears to be (1) 120V load (based on the existence of that yellow wire-which is in the same conduit as the blue and white 120V wiring). >>> This yellow wire is also in need of further clarification. <<<<

As I previously made reference to, the 120V yellow wire is PIN#2 on the front row of the block on the Tork 7300 manual timer.
We do know that when the timer is set in the Manual ON position, PIN #2 is hot. (read using white "neutral" to PIN #2="Hot")

We need to do a bit more research and testing to figure out the system as there is no electrical blueprint available to us.

I appreciate your willingness to help us resolve this. Let me get back to with more data. Thanks!:thumbsup:
 
Cal1947

Cal1947

RichardinVA said:
I (we believe) there are (2) lighting circuits 208V controlled by the existing manual style 24-hr/7day timer. This will need to be verified on Monday when we return to the site.

Additionally there appears to be (1) 120V load (based on the existence of that yellow wire-which is in the same conduit as the blue and white 120V wiring). >>> This yellow wire is also in need of further clarification. <<<<

As I previously made reference to, the 120V yellow wire is PIN#2 on the front row of the block on the Tork 7300 manual timer.
We do know that when the timer is set in the Manual ON position, PIN #2 is hot. (read using white "neutral" to PIN #2="Hot")

We need to do a bit more research and testing to figure out the system as there is no electrical blueprint available to us.

I appreciate your willingness to help us resolve this. Let me get back to with more data. Thanks!:thumbsup:
Click to expand...
. The timer could be controlling a lighting contactor
 
Personally I would talk them out of a digital timer and suggest replacing the old one with one just like it. Those old style mechanical time clocks are rock solid. I find most of the new digital ones to be unreliable.
 
iwire said:
Personally I would talk them out of a digital timer and suggest replacing the old one with one just like it. Those old style mechanical time clocks are rock solid. I find most of the new digital ones to be unreliable.
Click to expand...
I've had the exact opposite experience. Mechanical timers need adjusted every time the power goes out for an extended period. The digital I have has a built-in battery for the timer, which I've only replaced once in five years. Has an astral timer function, which mechanical needs a supporting accessory (e.g. photocell) to accomplish that.

The only problem I have is mine doesn't have a daylight savings time function... :D
 
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