Hi,
First post.
I've put together a control system for a small refrigerator to use as a curing chamber for meats. The refrigerator is a simple thing, not frost free, no fans, just a small freezer compartment in the top right corner that cools the whole thing. Per the label, it's a 0.9A load. I have placed a small humidifier (20W), a small dehumidifier (23W) and a small fan (1.25W) inside the refrigerator.
This simplified schematic represents what I have wired inside a box on top of the refrigerator. Add another identical circuit segment to see how the third controller would be wired. I left that out as I felt it was redundant within the context of this inquiry. Minor discrepancies exist in the schematic supplied. They are: an indicator LED is paralleled with outlet 3 that I forgot to add to the schematic and LED 1 and 2 are swapped. My bad. Sorry if any of that causes any real confusion.
The scheme is to use a WH8040 controller (ref. 4 below) to operate the humidifier (ref. 9,) another WH8040 to control the dehumidifier (ref. 8.) One WH8040 can't do both. An STC-1000 temperature controller (ref. 2) to operate the refrigerator (ref. 6.) All of the controllers have relay outputs (ref. 3 and 5.) Notice all controllers are paralleled to relays (ref. 1) that are used to power outlet 3 which is connected to the fan (ref. 7.) The point of those relays is to only power that outlet and fan if any or all of the controlled outlets are energized. If all the controllers outputs are off then the fan/outlet 3 is off too. The LED's are merely 120VAC indicator lights. Everything is wired with 18 gauge stranded wire which is rated for 10A.
Pretty straight forward it would seem. It works fine often. However it fails often too.
What happens?
How it works: If any one of the controllers meets it's turn on set point, it's internal relay energizes and closes it's switch applying 120VAC, the indicator LED comes on, it's controlled outlet gets energized, that load powers up, the downstream relay energizes and the outlet 3/fan comes on. All good. If another controller gets involved, all good too.
How it fails: Sometimes though, when one of the controllers after powering everything for a while meets its turn off set point, that controllers relay switch DOES NOT OPEN and the controlled load stays powered even though the controller indicates that it's output relay has been de-energized. I can hear the controllers output relay clicking when the turn off set point is reached so it would seem the relays solenoid is trying to open the switch.
I've changed all the outlet 3 controlling relays. No change. What is happening and how do I fix it?
1. - Schneider electric RPM11F7 120VAC - 15A / 250VAC https://www.schneider-electric.com/...-relay---zelio-rpm---1-c-o---120-v-ac---15-a/
2. - STC-1000 temperature controller : https://images-na.ssl-images-amazon.com/images/I/B1kOAUuVDWS.pdf
3. - Output relay contact capacity : Cool 10A/250VAC; Heat 10A/250VAC https://www.google.com/url?sa=t&rct...HF3FF_en.pdf&usg=AOvVaw1TYnv_2PXR_TA3j8gweTjP
4. - WH8040 Humidity controllers are these: http://usefulldata.com/wp-content/uploads/2016/05/humidity-controller-mh13100_manual-download.pdf.
5. - Contact capacity : 5A/250VAC https://octopart.com/lz-12vm-k-fujitsu-796258
6. - Refrigerator : 2.5 cubic foot, non-frost free, 120VAC 0.9 amps per label
7. - Muffin fan : 120VAC 5/4 Watts per label
8. - Dehumidifier : 9VDC 23 Watts per manual. Plug in power supply.
9. - Humidifier : 120VAC 20W ultrasonic
I hope I've met the requirements for a respectful and serious inquiry. I need an answer to this. Thanks for any help you might provide
First post.
I've put together a control system for a small refrigerator to use as a curing chamber for meats. The refrigerator is a simple thing, not frost free, no fans, just a small freezer compartment in the top right corner that cools the whole thing. Per the label, it's a 0.9A load. I have placed a small humidifier (20W), a small dehumidifier (23W) and a small fan (1.25W) inside the refrigerator.
This simplified schematic represents what I have wired inside a box on top of the refrigerator. Add another identical circuit segment to see how the third controller would be wired. I left that out as I felt it was redundant within the context of this inquiry. Minor discrepancies exist in the schematic supplied. They are: an indicator LED is paralleled with outlet 3 that I forgot to add to the schematic and LED 1 and 2 are swapped. My bad. Sorry if any of that causes any real confusion.
The scheme is to use a WH8040 controller (ref. 4 below) to operate the humidifier (ref. 9,) another WH8040 to control the dehumidifier (ref. 8.) One WH8040 can't do both. An STC-1000 temperature controller (ref. 2) to operate the refrigerator (ref. 6.) All of the controllers have relay outputs (ref. 3 and 5.) Notice all controllers are paralleled to relays (ref. 1) that are used to power outlet 3 which is connected to the fan (ref. 7.) The point of those relays is to only power that outlet and fan if any or all of the controlled outlets are energized. If all the controllers outputs are off then the fan/outlet 3 is off too. The LED's are merely 120VAC indicator lights. Everything is wired with 18 gauge stranded wire which is rated for 10A.
Pretty straight forward it would seem. It works fine often. However it fails often too.
What happens?
How it works: If any one of the controllers meets it's turn on set point, it's internal relay energizes and closes it's switch applying 120VAC, the indicator LED comes on, it's controlled outlet gets energized, that load powers up, the downstream relay energizes and the outlet 3/fan comes on. All good. If another controller gets involved, all good too.
How it fails: Sometimes though, when one of the controllers after powering everything for a while meets its turn off set point, that controllers relay switch DOES NOT OPEN and the controlled load stays powered even though the controller indicates that it's output relay has been de-energized. I can hear the controllers output relay clicking when the turn off set point is reached so it would seem the relays solenoid is trying to open the switch.
I've changed all the outlet 3 controlling relays. No change. What is happening and how do I fix it?
1. - Schneider electric RPM11F7 120VAC - 15A / 250VAC https://www.schneider-electric.com/...-relay---zelio-rpm---1-c-o---120-v-ac---15-a/
2. - STC-1000 temperature controller : https://images-na.ssl-images-amazon.com/images/I/B1kOAUuVDWS.pdf
3. - Output relay contact capacity : Cool 10A/250VAC; Heat 10A/250VAC https://www.google.com/url?sa=t&rct...HF3FF_en.pdf&usg=AOvVaw1TYnv_2PXR_TA3j8gweTjP
4. - WH8040 Humidity controllers are these: http://usefulldata.com/wp-content/uploads/2016/05/humidity-controller-mh13100_manual-download.pdf.
5. - Contact capacity : 5A/250VAC https://octopart.com/lz-12vm-k-fujitsu-796258
6. - Refrigerator : 2.5 cubic foot, non-frost free, 120VAC 0.9 amps per label
7. - Muffin fan : 120VAC 5/4 Watts per label
8. - Dehumidifier : 9VDC 23 Watts per manual. Plug in power supply.
9. - Humidifier : 120VAC 20W ultrasonic
I hope I've met the requirements for a respectful and serious inquiry. I need an answer to this. Thanks for any help you might provide