Defrost timer mounted inside walk-in freezer?

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sw_ross

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Do you see/have problems with the idea of mounting the time clock in the freezer?

This walk-in is located outside and is detached from the building by about 3 feet.

It would greatly simplify the installation if there wasn't a problem with doing this.

Thanks!
 
Do you see/have problems with the idea of mounting the time clock in the freezer?

This walk-in is located outside and is detached from the building by about 3 feet.

It would greatly simplify the installation if there wasn't a problem with doing this.

Thanks!
Will the timer work at freezer temperatures? Our domestic freezer runs at -25C which is about -13F. Not sure how or if electrical/electronic components would survive that.
 
Electric components will be fine. Lubricants on mechanical components is what may have issues in low temp extremes.

That said timer motor will generate some heat, and will be a little warmer inside the enclosure then it is outside. That alone should help prevent condensation within that enclosure.
 
Thanks!

Thanks!

Electric components will be fine. Lubricants on mechanical components is what may have issues in low temp extremes.

That said timer motor will generate some heat, and will be a little warmer inside the enclosure then it is outside. That alone should help prevent condensation within that enclosure.

Thanks for the help!
 
Electric components will be fine. Lubricants on mechanical components is what may have issues in low temp extremes.
The timers we commonly use are specified as -10C to +50C.
The OP needs to check the spec on his.
 
It's a Paragon, model # 8145-20.

I'll look at it closer when I get to the job today regarding any temp limitations.
 
Do you see/have problems with the idea of mounting the time clock in the freezer?

This walk-in is located outside and is detached from the building by about 3 feet.

It would greatly simplify the installation if there wasn't a problem with doing this.

Thanks!

Its better practice not to do so because things can often get very wet inside walk in freezers under various operating conditions in temperate zones, and with varying quality of moisture sealing practices.Also, its better not to have that clock where non-professionals can lay hands on it, again with it being potentially quite wet.
Most modern condensing units are set up to have the timer mounted inside the cabinet. This means one control conduit run from the CU to the Evaporator which you should need in most cases anyway with 240V electric defrost systems.
 
... timer motor will generate some heat, and will be a little warmer inside the enclosure then it is outside. That alone should help prevent condensation within that enclosure.
"Some": 5 watts, maybe, which won't be nearly enough to prevent condensation, nor to keep the mechanical parts up to -10°C. (if applicable)
 
If you can mount it on the roof of the cold box that is what I would do. Make a unistrut brace for it out of 2 pieces of strut and a 90 degree strut connector. Bolt one leg of the strut angle to the roof of the box and let the other end stand straight up. Support the timer off of that. Run liquid tite down into the box to the fan coil.
 
"Some": 5 watts, maybe, which won't be nearly enough to prevent condensation, nor to keep the mechanical parts up to -10°C. (if applicable)
5 watts in a ~100 cubic inch enclosure is plenty of heat to lessen condensation effects within that enclosure. I never said it would prevent it just that it may help.
 
Timer Choices

Timer Choices

The so called modern Solid State hybrid time clocks I have enocuntered in the field thusfar, I would not give a thin dime for. Unless someone has made a better one that I have not seen, they are unreliable on a good day.
I was assuming Electromechanical unit as in Paragon timer which is one of the best for the job and of course has line voltage behind a cardboard protector that is very easily removed. Laypersons should not have access to the defrost clock.
While there are a number of ways these units can be set up, the easiest way is not always the best, and when troubleshooting by sequence of operation, the HVAC guy is going to want the timer at the condensing unit for very specific reasons. Getting the LP control correctly set is the first one and that setting is going to vary with location and refrigerant type. It allows a quick test of all functions on the control set [ Serial Thermostat connection, Timer N.C contacts, Timer N.O. contacts, Pumpdown cycle and so forth] without having to run around and up and down ladders or all over creation.
A LOT of solid state controls as used in lower end HVAC machines is by nature unstable and very poorly engineered from a ruggedness and reliability standpoint.
Every service Engineer I know who has been in the trade for more than 20 years has changed out " too many " circuit boards." Period. Full stop.
It interesting to note that when you get into Chillers and other types of rigs from 150 to 1000 tons of capacity and up, how the reliability of said components suddenly becomes better in many cases. The unreliability and shoddiness is built in otherwise and will keep you running when you may have better things to do.
There are other modern so called devices in widspread usage and people just seem to think this is the way things have to be....
The are time bandits.
 
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