General Dehumidifer Question

[nickthesafe]

Hi folks, newbie here so be gentle, please.

Since i didn't want to trash a perfectly good refrigeration dehumidifer due to the defrost control board being fried and no replacement available, I've installed a programmable commercial defrost controller and need a little help with optimum setup parameters;

It's a small but very useful amcor TC120 which has an NTC probe mounted in the air stream immediately before the evaporator so it actually senses incoming air temp and not evap temp, as far as I can make out, this is only useful when the ambient temp is too low for the unit to function, I need to input this temp and expect it to be around 4degrees c or so..

Next up is the ON and OFF time for the compressor, I've got her running for 20 minutes followed by a 255 second defrost time which is pulling water quite well but if it can be better then I would love to hear.

Many Thanks.
Nick

[Magoo]

Run the compressor longer continuously and monitor any ice formation on evaporator, lift the setting for air on controller, that should protect possibility of ice formation.

[Magoo]

The condensate tank will have a cut out sensor controlled from the redundent PCB. Sort that into the new controller somehow, otherwize water spillage will happen for sure.

[nickthesafe]

Thanks for the replies...

The tank cut off is seperate and cuts power to the controller which is ok i've set up a one minute pause on power up to keep the comp from having a fit... As for Ice formation, well that begins within just a couple of minutes but i am loathed to cycle the compressor that often...Kinda homing in on around 15 minutes on and four minutes off, getting some ice build up followed by a quick defrost and a healthy run off into the tank. If it's OK to cycle the comp more quickly, I'll do that instead....what do you think?

Nick

[install monkey]

be careful in shortening the off period,you have to allow time for system pressures to stabilise otherwise your going to encounter more problems dont go under 3 mins

Thanks for the replies...

The tank cut off is seperate and cuts power to the controller which is ok i've set up a one minute pause on power up to keep the comp from having a fit... As for Ice formation, well that begins within just a couple of minutes but i am loathed to cycle the compressor that often...Kinda homing in on around 15 minutes on and four minutes off, getting some ice build up followed by a quick defrost and a healthy run off into the tank. If it's OK to cycle the comp more quickly, I'll do that instead....what do you think?

Nick

[nickthesafe]

Thanks IM... I'll bear that in mind. Job done. :-)

[Magoo]

Depending on the air on temp to evaporator, the rapid icing could indicate low air flow or system undercharge. You might be trying to mask over someother problems that cooked the original PCB and failure. Generally the off coil condition is slightly below the wet bulb condition to squeeze out moisture and condenser reheats out going air, raising the dry bulb condition thus low humidity.

[shooter]

Mount the NTC on the evaporator as it is now, as soon as temp drops below 4 Celsius stop the unit, as there will be ice on the evaporator, and this will deminish the capacity.
The unit should be able to run continously when the airtemp is high enough.

[nickthesafe]

That makes more sense, the probe fits into a clip which mounts on the evaporator but it is seperated by a plastic shield from the evap, it's currently running at between 14 and 20 degrees depending on the air temp in my bathroom but i can see problems in the summer when humidity rises and the unit still wants to operate timed rather than temperature. I'll get the probe mounted to the evap and do it that way.. Thanks Guys