measuring doubled amps on unbalanced 240 loads with two CT

[bridqer]

Last week My GEM/Dashbox began report a sudden increase of power comsumption by my heatpump/AC condensor previously it reported typical usage of about 850-900watts and 7-8 amps. Then just 40 minutes later it start reporting 1600-1800watts and 14-15amps.
When it goes into defrost mode the fan turns off and only the compressor runs. It used to drop to 600-650 watts and 5-6amps. Now it is 900-1300watts and 9-12amps.
The Condensor is a 2.5ton unit with a compressor Rated Load Amps of 14.1amp and a fan Full Load Amps of .5amp
Amps measured at the condensor with a clamp meter is 6.6 on one leg and 6.8 on the other. Just the compressor motor is about 5amps
I have CTon both legs running the condensor.

After typing all this out I pulled one of the CT leads out of the GEM channel terminal and the reading whent back to what they were before. I decided there was a CT wire not making contact in the GEM terminal and that it got bumped to make contact when I took the cover off to the GEM last week to see how many channels were left to add another monitored circuit. I have a whole year of incorrect data for the HVAC condensor.
Now though it has brought to my attention that before it used to report the correct amps but the watts was incorrect, now the watts are about right and the amps are double. My other unbalanced 240 circuits(oven range, dryer) have this same problem with the amps. My dryer shows about 4900watts and 41amps. What is the setting to correct the amps when both leads are monitored on a 240v circuit?

[Teken]

Hello,

Can you offer some image captures from both the DB and GEM settings? In the GEM provide what the CT’s are selected and their settings. The same for the Dash Box.

The more details you can share the easier it will be to troubleshoot and offer a fix.

Please also show what the PT settings are and what the GEM indicates as the incoming monitored line voltage.

Also, if you have modified any CT settings to obtain higher accuracy you should consider returning them to the default values while you identify where the faults are.

Lastly, please confirm you have wired the respective CT in accordance to the GEM manual as they can be wired incorrectly. This also applies to selecting the 240 doubling feature when only one CT is in use.

All newer GEMS have a PCB cover plate which calls out how to wire all types of CT’s.


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[ben]

Last week My GEM/Dashbox began report a sudden increase of power comsumption by my heatpump/AC condensor previously it reported typical usage of about 850-900watts and 7-8 amps. Then just 40 minutes later it start reporting 1600-1800watts and 14-15amps.
When it goes into defrost mode the fan turns off and only the compressor runs. It used to drop to 600-650 watts and 5-6amps. Now it is 900-1300watts and 9-12amps.
The Condensor is a 2.5ton unit with a compressor Rated Load Amps of 14.1amp and a fan Full Load Amps of .5amp
Amps measured at the condensor with a clamp meter is 6.6 on one leg and 6.8 on the other. Just the compressor motor is about 5amps
I have CTon both legs running the condensor.

After typing all this out I pulled one of the CT leads out of the GEM channel terminal and the reading whent back to what they were before. I decided there was a CT wire not making contact in the GEM terminal and that it got bumped to make contact when I took the cover off to the GEM last week to see how many channels were left to add another monitored circuit. I have a whole year of incorrect data for the HVAC condensor.
Now though it has brought to my attention that before it used to report the correct amps but the watts was incorrect, now the watts are about right and the amps are double. My other unbalanced 240 circuits(oven range, dryer) have this same problem with the amps. My dryer shows about 4900watts and 41amps. What is the setting to correct the amps when both leads are monitored on a 240v circuit?

Are these split or solid-core CTs? If split, make sure the contacts on the CT haven't come loose.

We sampling each side of the breaker and using a 120V reference, so it's showing the amperage we're sampling from the CTs. When it comes to a 240V circuit with a neutral, it isn't possible to monitor without measuring the amperage at both ends.

If you'd prefer to see the amperage as half, try increasing the CT range by 1 and turning on the X2 setting.