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Hi all,

I am modeling a PIU system w/ a water-cooled DX coil and series electric FPBs; no central or preheat heating coils. Using eQ v3.64, but have also observed this in eQ v3.65.

SV-A report indicates heating capacity for system is 0.

Despite this configuration, hourly reports of for SYSTEM, 'Total central heat coil output (Btu/hr)' indicates there is varying amount of central heat energy output in the first 1-2 and in some cases, the last 2-3 hours of many days in heating months (location Seattle, WA). This is also confirmed by looking at the difference in energy reported between SS-A Heating and SS-B Zone Heating. It is not necessarily a trivial amount of energy, ~10-25% of total system heating in two models I've tested.

Have others observed this before, and if so, found a way to fix this?

Can't say I've tried everything I can think of, but this is what I have tried:

1. Specify HEAT-SOURCE = "NONE" and leave HEAT-SET-T undefined
2. Set HEAT-SOURCE = "ELECTRIC" and use a very small capacity both -1 or -1000
3. 2 + setting HEAT-CONTROL = "CONSTANT"
4. 3 + set HEAT-SET-T various values, including minimum (50F)
5. Setting HEATING-SCHEDULE to something that locks out heating. This works, but also locks out zone heating, so not a viable solution.

Below is a link to some dirty wizard model that illustrates the issue (you will need to download the weather .bin file or change to something to be comparable). This is representative of the configuration I was going for except this model uses air-cooled DX.

eQ-364_PIU Tests

Thanks in advance for any input.

Hi all,

I am modeling a PIU system w/ a water-cooled DX coil and series electric FPBs; no central or preheat heating coils. Using eQ v3.64, but have also observed this in eQ v3.65.

SV-A report indicates heating capacity for system is 0.

Despite this configuration, hourly reports of for SYSTEM, 'Total central heat coil output (Btu/hr)' indicates there is varying amount of central heat energy output in the first 1-2 and in some cases, the last 2-3 hours of many days in heating months (location Seattle, WA). This is also confirmed by looking at the difference in energy reported between SS-A Heating and SS-B Zone Heating. It is not necessarily a trivial amount of energy, ~10-25% of total system heating in two models I've tested.

Have others observed this before, and if so, found a way to fix this?

Can't say I've tried everything I can think of, but this is what I have tried:

1. Specify HEAT-SOURCE = "NONE" and leave HEAT-SET-T undefined
2. Set HEAT-SOURCE = "ELECTRIC" and use a very small capacity both -1 or -1000
3. 2 + setting HEAT-CONTROL = "CONSTANT"
4. 3 + set HEAT-SET-T various values, including minimum (50F)
5. Setting HEATING-SCHEDULE to something that locks out heating. This works, but also locks out zone heating, so not a viable solution.

Below is a link to some dirty wizard model that illustrates the issue (you will need to download the weather .bin file or change to something to be comparable). This is representative of the configuration I was going for except this model uses air-cooled DX.

eQ-364_PIU Tests

Thanks in advance for any input.

Hi all,

I am modeling a PIU system w/ a water-cooled DX coil and series electric FPBs; no central or preheat heating coils. Using eQ v3.64, but have also observed this in eQ v3.65.

SV-A report indicates heating capacity for system is 0.

Despite this configuration, hourly reports of for SYSTEM, 'Total central heat coil output (Btu/hr)' indicates there is varying amount of central heat energy output in the first 1-2 and in some cases, the last 2-3 hours of many days in heating months (location Seattle, WA). This is also confirmed by looking at the difference in energy reported between SS-A Heating and SS-B Zone Heating. It is not necessarily a trivial amount of energy, ~10-25% of total system heating in two models I've tested.

Have others observed this before, and if so, found a way to fix this?

Can't say I've tried everything I can think of, but this is what I have tried:

1. Specify HEAT-SOURCE = "NONE" and leave HEAT-SET-T undefined
2. Set HEAT-SOURCE = "ELECTRIC" and use a very small capacity both -1 or -1000
3. 2 + setting HEAT-CONTROL = "CONSTANT"
4. 3 + set HEAT-SET-T various values, including minimum (50F)
5. Setting HEATING-SCHEDULE to something that locks out heating. This works, but also locks out zone heating, so not a viable solution.

Below is a link to some dirty wizard model that illustrates the issue (you will need to download the weather .bin file or change to something to be comparable). This is representative of the configuration I was going for except this model uses air-cooled DX.

eQ-364_PIU Tests

Thanks in advance for any input.

Hi all,

I am modeling a PIU system w/ a water-cooled DX coil and series electric FPBs; no central or preheat heating coils. Using eQ v3.64, but have also observed this in eQ v3.65.

SV-A report indicates heating capacity for system is 0.

Despite this configuration, hourly reports of for SYSTEM, 'Total central heat coil output (Btu/hr)' indicates there is varying amount of central heat energy output in the first 1-2 and in some cases, the last 2-3 hours of many days in heating months (location Seattle, WA). This is also confirmed by looking at the difference in energy reported between SS-A Heating and SS-B Zone Heating. It is not necessarily a trivial amount of energy, ~10-25% of total system heating in two models I've tested.

Have others observed this before, and if so, found a way to fix this?

Can't say I've tried everything I can think of, but this is what I have tried:

1. Specify HEAT-SOURCE = "NONE" and leave HEAT-SET-T undefined
2. Set HEAT-SOURCE = "ELECTRIC" and use a very small capacity both -1 or -1000
3. 2 + setting HEAT-CONTROL = "CONSTANT"
4. 3 + set HEAT-SET-T various values, including minimum (50F)
5. Setting HEATING-SCHEDULE to something that locks out heating. This works, but also locks out zone heating, so not a viable solution.

Thanks in advance for any input.