# Change from manual timer to digital



## RichinVA (Feb 7, 2015)

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 is the specs on the in-place "Manual" 24-hour Time Switch "with skip a day"
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.

Here is 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 (which I am unsure of what that stands for?) OK, I am including links to the wiring diagrams for both here below.

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

My question concerns this: The Tork 7300 Manual Timer is a 3PST, while the DG100A is a SPDT. 

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

Any suggestions? Comments? Help?


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## Black Dog (Oct 16, 2011)

SPST=single pole double throw.

DPDT=double pole double throw.

Welcome to the forum..:thumbsup:

Also how many loads do you have?


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## RichinVA (Feb 7, 2015)

*Clear up a couple of things..*



Black Dog said:


> SPST=single pole double throw.
> 
> DPDT=double pole double throw.
> 
> ...


From what I can dig up...
SPST = SINGLE POLE SINGLE THROW
SPDT = SINGLE POLE DOUBLE THROW
DPST = DOUBLE POLE SINGLE THROW
DPDT = DOUBLE POLE DOUBLE THROW
3PDT = THREE POLE DOUBLE THROW

And what I am dealing with is the Manual Timer (*Tork 7300) is a 3PST* switch, while the Digital Timer (*Tork DG100A) is a DPDT switch*.

I think you made a typo because you have this: "SPST=single pole double throw" ? I am sure you meant SPDT? But that is not applicable here?

OK.. from a J-box marked 120V, there are 3 wires entering the manual switch from the bottom of the enclosure via a steel conduit. 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) linked in previous post 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 manual switch (Tork 7300) a Blue Jumper Wire is used and connects "L" and Pin #1 on the "Front" row. (See diagram of Tork 7300).

The 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).

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

Does this help?


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## RichinVA (Feb 7, 2015)

Whoops I also did a typo here "My question concerns this: The Tork 7300 Manual Timer is a 3PST, while the DG100A is a *SPDT*"

The DG100A is a *DPDT* (doublepoledoublethrow) switch. Guess I am tired.?


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## Bad Electrician (May 20, 2014)

RichinVA said:


> 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 f


A Manual timer is a finger, I think you mean is typically referred to as analog or even old school.


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## RichinVA (Feb 7, 2015)

*Old school is right*



Bad Electrician said:


> A Manual timer is a finger, I think you mean is typically referred to as analog or even old school.



Yes the in place is an old school analog type clock timer. Thanks for your help.

Have you looked at the two different wiring diagrams that are linked here?

I am trying to determine if the digital timer is a compatible alternative. I do have to verify what loads the current analog timer is switching on and off.


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## varmit (Apr 19, 2009)

If you have more circuits to control than there are useable timer contacts, install a contactor (rated for the loads connected) with the contactor coil controlled by the timer.


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## RichinVA (Feb 7, 2015)

varmit said:


> If you have more circuits to control than there are useable timer contacts, install a contactor (rated for the loads connected) with the contactor coil controlled by the timer.


Thanks Varmit!

My confusion comes in because the supplier sold us the Tork DG100A Digital Timer to replace the Tork 7300 clock timer and they said it is the digital equivalent.

The 7300 is 3PST and the DG100A is a DPDT??


If you look at the diagrams and read my notes above you will see that what I believe are (2) 208 loads (one Blue and one Blk) on pins #3 and #5 and being closed through #4 and #6 respectfully via the white wire and the yellow wire.

On the "front row" The 120 power comes to "L" Pin and to #1 (via a jumper) This powers the 120V clock motor.

The 120volt yellow wire so far is a mystery. When the 120V power is on and the clock timer is flipped to "Manual On" , Pin #2 is energized 120V (closed circuit). Any idea on this ? Could it be the lighting starter (or similar nomenclature?)


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## NacBooster29 (Oct 25, 2010)

I hate to be that guy. But you seem to be over your head. Are you a plumber changing a timer for a water heater?


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## JDJ (Aug 9, 2011)

Ibtl


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