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Update Rule23-1.md #1434

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14 changes: 7 additions & 7 deletions docs/section23/Rule23-1.md
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Expand Up @@ -36,15 +36,15 @@
- get the hvac system from the hvac_system_id: `hvac_system = get_component_by_id(hvac_system_id)`
- get the heating system: `heating_system = hvac_system.heating_system`
- get the heatpump_low_shutoff_temperature = `heatpump_low_shutoff = heating_system.heatpump_low_shutoff_temperature`
- get the auxiliary heat high temperature shutoff = `aux_heat_high_temp_shutoff = heating_system.heatpump_auxilliary_heat_high_shutoff_temperature`
- get the auxiliary heat energy source: `aux_heat_energy_source = heating_system.heatpump_auxilliary_heat_type`

**Rule Assertion:**
- Case 1: The system type is 2 and the heatpump_low_shutoff is <= 17F, PASS: `if system_type == HVAC_SYS.2: if heatpump_low_shutoff <= 17: PASS`
- Case 2: The system type is 2 and the heatpump_low_shutoff is >25F, FAIL, provide a message: `elif system_type == HVAC_SYS.2:`
- `if heatpump_low_shutoff > 25: FAIL; note = "Fail because low temperature heat pump shutoff is above 25F for system 2. The modeled low temperature heat pump shutoff value is " + heatpump_low_shutoff
+ "."`
- Case 3: the system type is 2 and the heatpump_low_shutoff is between 17F and 25: UNDETERMINED; provide a message: `else: UNDETERMINED; note = "Undetermined because the low temperature shutoff is between 17F and 25F for System Type 2. Check with the rating authority to ensure correct shutoff temperature. Low shutoff temperature is currently modeled at: " heatpump_low_shutoff = "."`
- Case 4: the system type is 4 (we already know it's 4, because we've checked the 3 SYS 2 cases above), and the low shutoff temperature is <=10F: PASS: `if heatpump_low_shutoff <= 10F: PASS`
- Case 5: anything else, FAIL: `ELSE: Fail`
- Case 1: The auxiliary heat high temperature shutoff is greater than 40F, or the auxiliary heat energy source is anything other than electricity - FAIL: `if (aux_heat_high_temp_shutoff > 40) or (aux_heat_energy_source != "ELECTRIC_RESISTANCE"): FAIL`
- Case 2: The system type is 2 and the heatpump_low_shutoff is <= 17F OR tye system type is 4 and the heatpump_low_shutoff is <=10F, PASS: `if(system_type == HVAC_SYS.2 and heatpump_low_shutoff <= 17) or (system_type == HVAC_SYS.4 and heatpump_low_shutoff <= 10): PASS`
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@claperle claperle Nov 5, 2024 •
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There is no Appendix G basis for this, correct? Based on recent discussions within the commitee, I am not sure we should be making these assumptions; I know we decided on this approach previously but wonder if it is still appropriate. It does seem like a no brainer to use 17F but not sure about the 10F since there were comments about us "interpreting" 90.1 requirements which this kind of falls into.

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I think that these minimum numbers come from the minimum temperature at which the heat pumps are rated based on the AHRI conditions from Table 6.8.1-2

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... but open to discussion.

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I don't think 10F is in those tables. 17F is though.

- Case 3: The system type is 2 and the heatpump_low_shutoff is >25F, FAIL, provide a message: `elif system_type == HVAC_SYS.2 and heatpump_low_shutoff > 25:`
- `FAIL; note = "Fail because low temperature heat pump shutoff is above 25F for system 2. The modeled low temperature heat pump shutoff value is " + heatpump_low_shutoff + "."`
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Same question of the 25F heat pump low shut off for System 2. Is this an interpretation from our side or is there a requirement that states this that I'm missing?

- Case 4: the system type is 2 and the heatpump_low_shutoff is between 17F and 25: UNDETERMINED; provide a message: `else: UNDETERMINED; note = "Undetermined because the low temperature shutoff is between 17F and 25F for System Type 2. Check with the rating authority to ensure correct shutoff temperature. Low shutoff temperature is currently modeled at: " heatpump_low_shutoff = "."`

**Notes:**

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