HVAC Monitor and other

Savoy

New Member
HVAC Monitor Wiring

The only info I could find on wiring for the HVAC monitor is in this forum. I want to make sure that my understanding is correct before I proceed.

1. "You need to attach common to the GND terminal". Is the 24vac common is connected to the same terminal as the 1-wire return?

2. In the product description at the hobby boards site it states. "It has 4 channels so it can monitor... or heat and cool on two different units." Are the two different commons from the 2 separate 24vac power sources connected to the same terminal as the 1-wire return?

3. At the hobby boards site it states. "To connect devices using the RJ45s, you can simply use standard network cables." Also on the wiring diagram page it shows 4 & 5 used for the 1-wire connection. All the standard network cables I have, don’t seem to have anything connected to 4 & 5.

As a suggestion about the 4 channel relay board. It would be nice to have a version with NO and NC contacts. I use relays to add an additional layer of control to thermostat and other types of circuits by opening the circuits using the normally closed contacts. That way if the computer that is controlling things fails, everything will work ok, just as it did before I added the additional control layer. Now, I will use slave relays connected to 4 channel board to achieve the same result, so, it’s not a problem.

Thanks
 

ericvic

Active Member
HVAC Monitor Wiring

The only info I could find on wiring for the HVAC monitor is in this forum. I want to make sure that my understanding is correct before I proceed.

1. "You need to attach common to the GND terminal". Is the 24vac common is connected to the same terminal as the 1-wire return?
Yes
2. In the product description at the hobby boards site it states. "It has 4 channels so it can monitor... or heat and cool on two different units." Are the two different commons from the 2 separate 24vac power sources connected to the same terminal as the 1-wire return?
Yes. The common on 24vac power supplies of the HVAC units should be floating and will be no problem hooking them together.
3. At the hobby boards site it states. "To connect devices using the RJ45s, you can simply use standard network cables." Also on the wiring diagram page it shows 4 & 5 used for the 1-wire connection. All the standard network cables I have, don’t seem to have anything connected to 4 & 5.
That doesn't sound like a standard Ethernet network cable, because with a standard network cable all 8 pins will have a wire.
As a suggestion about the 4 channel relay board. It would be nice to have a version with NO and NC contacts. I use relays to add an additional layer of control to thermostat and other types of circuits by opening the circuits using the normally closed contacts. That way if the computer that is controlling things fails, everything will work ok, just as it did before I added the additional control layer. Now, I will use slave relays connected to 4 channel board to achieve the same result, so, it’s not a problem.

Thanks
I will add your comments about the relay to the wish list.

Eric
 
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