ozone control for geothermal dehumidifier

alec_t said:

As you have it won't the variac be permnently on/?

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I guess it would, but the blower only runs when the humidistat gives the blower power. I can change things around no problem.

Thanks ramuna I think! (; for that link. No really, thanks. I just figured metal would be impervious to O3. ugg. I was concerned about the 4" PVC in the system but it's more resistant to O3 than aluminum. Big surprise there. But if I only run O3 through the system for a minute a day, which is about what I plan to do, and it takes weeks to badly corrode the aluminum, It should outlive me.

20,160 minutes/2 weeks. 365 minutes ozone/year. The system should be toast in 55 years. I'll be pushing up daisies by then. Shoot, if I don't get with the program, I'll be pushing up daisies before the tank is done! Getting close though...

Thanks guys.

From the hookup schematic in post 5.

For starts, the plugs on the Variac and blower would be removed. I am sorry I did not recognize that earlier. I'll start tomorrow I hope.
Thanks.

I am not sure how to hook up the ‘live’ (not N) wire from the blower.

Will I need to open the variac to connect the ‘live’ wire from the blower or does that wire connect to the humidistat/variac/ coil ‘live’ wire?

I plan to connect the N and L wires as well as the ground from the blower and variac at the appliance timer.

Alec, you are so right-this arrangement is better than how I had it hooked up. I had not even considered the variac being left on. Beside the fact of O3 control.
Thanks a million!

edit: OK, I think I've got it-the blower 'live' wire goes to the hot wire in the receptacle on the variac. (where the blower plug would normally go)

For the variac, I plan to use the L and N wires from the plug of the variac for the hookup. Is that right?

This side of the pond L = Live = Hot.
To prevent my making wrong assumptions, can you please specify what inputs and outputs there are (i.e L, N, Gnd, screw terminals, plugs, sockets) on each of the variac, humidistat, ioniser, appliance timer and 5V supply.

alec_t said:

This side of the pond L = Live = Hot..

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I was not sure what to call the wire between the humidistat and variac-sometimes it's live and sometimes it's not so I called it 'live'.

I plan to use a digital timer like this. **broken link removed**

I was going to plug the 5V power supply into one of the timer's receptacles. Then tie the L wires from the coils together, the ground wires from the blower, humidistat and variac together and add the N wire to a corded plug. This would get plugged into the second timer receptacle.

EDIT; As I rolled out of bed it occurred to me that this corded plug will need to be plugged into a receptacle that's on the same mains circuit as the appliance timer, NOT into the appliance timer.

The 5V power supply has a two prong plug that goes into a 110V receptacle and a 2.1mm plug to supply 5V to the ozoniser timer.
The humidistat has three screw terminals one of which is ground.
The variac has a 110V plug with ground and a 110V receptacle with ground.
The ozoniser has a two prong plug. (I installed a dedicated receptacle for the ozoniser awhile ago and left a length of wire dangling. So, now I'm thinking of using that dangling wire for the ozoniser hookup.)
The blower has a 110V plug with ground.
Thank you, Alec.

I was not sure what to call the wire between the humidistat and variac-sometimes it's live and sometimes it's not

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It's a switched live; let's call it SL.
The timer connections aren't fully specified in the link. I assume the timer has a 3-pin input plug?
Does each timer outlet receptacle have SL, N and ground (G) contacts, for mating with a standard 3-pin mains plug?
Does the 5V supply plug fit the timer output receptacle?
Is the blower plug 3-pin?

Then tie the L wires from the coils together, the ground wires from the blower, humidistat and variac together and add the N wire to a corded plug. This would get plugged into the second timer receptacle.

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If I've understood you correctly that would result in the humidistat/blower operating only when the timer says 'on'. I thought you wanted the humidistat/blower to operate independently of the timer also, when the humidistat says 'on' ?

Here's how I'd hook up the system

alec_t said:

It's a switched live; let's call it SL.
The timer connections aren't fully specified in the link. I assume the timer has a 3-pin input plug?

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Yes.

alec_t said:

Does each timer outlet receptacle have SL, N and ground (G) contacts, for mating with a standard 3-pin mains plug?

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Yes.

alec_t said:

Does the 5V supply plug fit the timer output receptacle?

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Yes.

alec_t said:

Is the blower plug 3-pin?

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Yes.

alec_t said:

If I've understood you correctly that would result in the humidistat/blower operating only when the timer says 'on'. I thought you wanted the humidistat/blower to operate independently of the timer also, when the humidistat says 'on' ?

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That dawned on me when I woke up so I made a quick edit, but not quite soon enough. Sorry about that..So I'll get an appliance timer with a single receptacle to plug the 5V wall wart into.

Your hookup plan looks great! I'm pretty sure I understand it. Thanks for bearing with me. Thanks so much for that revision.

edit; Could the fuse in front of the appliance timer go immediately after the 5V power supply? Would you recommend about 60 mA?
The blower is 0.56A, 68W. For the surge resistant fuse in front of the humidistat, would either 1A or 1.6A be a good choice?

Could the fuse in front of the appliance timer go immediately after the 5V power supply? Would you recommend about 60 mA?

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The fuse was intended to protect against failure of the appliance timer as well as the downstream circuitry. Ideally, that's where it should be for maximum safety. Moving it would protect only the ozoniser timer and relay coils. Personally, for such low current circuitry, I'd regard that fuse as a luxury and probably omit it to simplify the wiring. Your call! Perhaps the appliance timer and 5V wall-wart would have their own internal fuses already?
The ozoniser timer draws negligible current. I don't know what your relay coil current is, but since both coils can be energised simultaneously the fuse (if used) should be rated for around twice the total coil current.
I'd suggest the 1.6A surge-resistant fuse for the blower.

Edit:
When wiring up the relays, the wire to/from the switching contacts needs to be chunky enough to carry the blower/ioniser current and should be kept at least 3mm away from the (thinner) wires feeding the coils.

Thanks Alec, I'll get it hooked up and let you know.

Everthing is hooked up and works except the ozoniser keeps repeating 1 minute cycles.

I plugged in the main plug and the variac and blower came to life. When I plugged in the 5V wall wart, the radio that's plugged in for the ozoniser and the LED came on for just a little over a minute, then they both turned off for a few seconds, then both came back on.

Any ideas? Thanks.

edit The humidistat over ride works flawlessly!

Any ideas?

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Hmm. Could be a power-on-reset glitch in the ozoniser timer. Try replacing C2 with a 100nF.

OK thanks, I'll try that after work.

I replaced C2, but no luck. It's still doing the same thing.

I'll try to find time tomorrow to go over the timer with a fine toothed comb.

they both turned off for a few seconds, then both came back on.

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I can't explain the 'few seconds' delay.
It's certainly worth double-checking the ioniser circuit itself. Another possibility is that electrical noise is causing a reset. Until we get this sorted try running the ozoniser timer without the variac/blower/radio connected, using just the LED as an indicator of timer action.

With the radio, variac and blower unplugged, there was no change in the timer behavior. There is about a 4 ½ second pause between cycles.
I went over the timer and could not find anything out of place.
I wonder if you could double check the IC connections.
Pin 3 from 4020 is connected to pins 1, 3, 5, 9 and 11 from 40106.
Pins 2, 4, 6, 8 and 10 from 40106 are connected to R5.
Pin 11 from 4020 is connected to R4.
Pin 10 from 4020 is connected to pin 12 from 40106 and R1.
Pin 13 from 40106 is connected to R2/D1.
Thanks.

Those connections are all as they should be. Good. And it looks as though current pulses from the radio etc aren't the culprit.
Check that C3 and C5 are in place, as close to the IC supply pins as possible.
Try re-flowing the joints of R3, R4 and D1, or replacing D1.

alec_t said:

Check that C3 and C5 are in place, as close to the IC supply pins as possible.

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That would be pins 14 and 16, right?

edit; I have the leads from C3 and C5 soldered directly to the Vdd and Vss pins. What I meant was, should those caps be moved closer to the Vdd pins?

That would be pins 14 and 16, right?

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Yes (for 40106 and 4020 respectively).
Not worth shortening the leads, provided they're directly soldered as you say.

I got some numbers from the diodes that don't make sense to me. These are all 1N4148 diodes. With the DMM on diode mode;

Brand new diode with negative probe on cathode 621, with probes reversed I got 1.

D1 with negative probe on cathode 628, with probes reversed I got 1939.

D2 with negative probe on cathode 72, with probes reversed I got 72.