Freeze protection for 240V no neutral wire

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PondScum

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Oct 11, 2007
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I have an old Intermatic electronic timer which I believe is equivalent to the current P1102ME timer. It has two wires for the 240V power, two wires for the pump, and a screw to attach the green ground wire. No neutral wire.

I wanted to add freeze protection (it freezes a few hours a night for about 3-4 weeks of the year here) so I bought an Intermatic PF1103T, but found it requires a neutral wire. What is my best course of action? In six months or so I plan to install a two-speed pump (for energy savings) and a salt water chlorine generator, so maybe it doesn't make sense to be spending any money on this.

Here's what I've thought of:

1) Have an electrician run a neutral wire to the timer (should the nearby panel have a neutral available so it's a simple job to run the wire?)

2) Sell the PF1103T on Ebay and buy a PF1102T (is this compatible with 240V w/no neutral wire?)

3) Don't bother because the equipment has survived nearly 20 years w/o freeze protection (I just program the pump to run at the coldest part of the night) and I'm planning a bunch of upgrades this year which will probably include some automation.
 
I suspect you are misunderstanding something. In a 120v installation you would have a single hot wire, a neutral wire, and a ground. In a 240v installation you would have two hot wires and a ground. Because the PF1103T works with both 120v and 240v it might have a terminal labeled neutral but that labeling should only apply to 120v applications. Only a circuit breaker panel would normally have two hot wires, a neutral, and a ground.
 
That's how my current timer is wired (240V uses two hot wires but not neutral). However, the P1103MT specifically states that the neutral wire must be used even for 240V applications. It says this right on the front page, and says to use the P1102T if you're using it in a 240V application and don't have the neutral wire available. Here is a table from their catalog.

intermaticbt4.png


The P1102T doesn't have the asterisk next to it, so it only uses the two hot wires.

I can scan the front page of the P1103MT manual if you'd like to see it.
 
PondScum,

If you are going to install a two-speed pump next year, you will also need some kind of timer that will switch between the two speeds. If you did not need freeze protection, I would recommend the mechanical timer Intermatic T10604R, which would cost somewhere between $150 and $200 on the Internet. I can not find any mechanical Intermatic timers which can handle both two speed motors and freeze protection, but it is possible that I am overlooking something.

You would have to upgrade to a digital timer Intermatic PE15300F in order to get two-speed motor control and freeze protection. This unit comes with a freeze probe and should cost between $360 and $440 on the Internet.

Edit: I didn't see your post before writing mine. It would be great if you could scan the wiring schematic - I can not seem to find this wiring schematic at the Intermatic website.

Titanium
 
Very curious. The digital section must be 120v only and they are using the neutral and one of the hot wires to power the timer. I wish they had manuals on their web site.

To get back to your original three questions:

1) Any panel with circuit breakers in it is nearly sure to have a neutral wire. Likewise, a junction box containing wires for both 120v and 240v circuits is nearly sure to have a neutral wire. If there is room in the conduit and good access then it is easy to run another wire. However, there can be situations where it is very difficult to add an additional wire, particularly buried conduit that is already full. If the wire run is a couple of feet this will probably be very simple. If it is from indoors to outdoors through underground conduit it might get very complicated.

2) Getting a PF1102T instead is also a good choice. If you sell your PF1103T and are planning to do the install yourself this is probably the least expensive approach. If you are having an electrician do the install in any case then running the wire might be simpler (depending on your situation).

3) Many of the automation systems include freeze protection.
 
PondScum,

A less expensive alternate for your two-speed motor and freeze protection might be the Intermatic PE153F, which can be found on the Internet for between $270 and $350. This is considerably less expensive than the Intermatic PE15300F ($360-$440) that I mentioned in my previous post.

Titanium
 
PondScum,

Thanks for taking the time to scan the Intermatic manual. Darn thing really does need a neutral! I know that you are going to wait awhile to upgrade the equipment, and as JasonLion mentioned above, adding a neutral could be childs play or could be exceedingly difficult all depending on your particular circumstances. We would probably need a photo of your electrical equipment at your equipment pad in order to gauge how easy or how hard of a job this would be.

SeanB,

Since Intermatic doesn't seem to have the PF1103MT manual at their website, is there anywhere to store this pdf at TFP for future reference?


Titanium
 
That is the one I am familiar with, the one that seems to be most popular. I hadn't run into the 1103 before except in the catalog. Curiously, they show the right picture for the PF1102MT, which is the same timer without the case. In some parts of their site they also list the PF1103T as 120v only, so sadly you need to be a little wary of anything you see at their site.
 

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