TREAT FAQ: Error Messages

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When we put in an AFUE figure for efficiency we often get the message that the heating system is too small. Is this false, as most of these buildings are in fact overheated?

On a typical day the building may be overheated due to system imbalance, high distribution losses, inadequate heating control, etc. However, on a few days when outdoor temperature falls to designed heating conditions the building may become underheated. Also, as part of load sizing, TREAT applies a user-specified heating safety factor to required heating input. The default value for the factor is 25%. TREAT reports insufficient heating system capacity if the load is met but not exceeded by the specified safety factor. You may choose to reduce the safety factor to compensate for the difference between steady state efficiency and AFUE for load sizing.

To establish the adequacy of the size of the heating system, I believe it is more correct to use the steady state efficiency. AFUE takes off-cycle and other losses into account that do not affect usable boiler output. I agree that steady state efficiency makes the most sense for determining required input capacity. However, our load sizing report presents required heating output capacity. You may choose to use steady state efficiency to convert it to required input capacity manually.    Return to Top

I modeled window unit air conditioners but no electricity appears in the Cooling kWh/ year section?

In order to enter complete cooling system information in TREAT it is not enough to describe the cooling system on Heating/ Cooling screen. You must also specify which spaces are cooled on the Thermostats screen by the setting Is Area Cooled box to Yes for such spaces. If you enter cooling system but have not entered cooling setpoints on the Thermostats screen, TREAT warns you about the possibility of incomplete input when you start model calculations. It displays a warning message "At least one thermostat in the project is heating only." In other words, if you have not specified cooling setpoint for any of the spaces in the project, TREAT assumes that air conditioner never operates. The criterion is used for the model and billing analysis period that is compared to that model.    Return to Top

When I mark the box to have it use our estimated base load numbers, it does not let me enter a value for the natural gas.

TREAT should let you enter the esimated base load values for all the fuels that are checked in the Fuels Used For Base Load area of the Analysis Periods screen. Note that if the analysis period is compared to model, this information is not editable on the Analysis Periods screen because it is taken directly from the model part.    Return to Top

Total room loads do not add up to equipment capacity.

The equipment capacity is not equal to the sum of the room loads because TREAT calculates the peak simultaneous load on the building, which may typically does not coincide with the peak load on each room.

The difference between space load and equipment load is covered in notes 3 and 5 of the report. Please let me know if you want to add other explanations.    Return to Top

What is this reality check? It gives me a message saying that the reference temp. 36.83 F is not in the expected interval. But I have not mentioned this value as a reference temp. anywhere.

The reference temperature is calculated by TREAT based on your model inputs. A reference temperature of 36F means that your building requires heating only when the outdoor temperature falls below 36F. This is unusually low. Typical reasons for that is very high heat gains from lighting, appliances or DHW along with very low infiltration/ mechanical ventilation rate and high wall R-values.    Return to Top

Billing Analysis won't run?

Billing analysis in the current version of TREAT requires that there is at least one actual bill in the analysis period for each metered space.

For Example, several metered spaces in a database had a single actual bill OUTSIDE the user defined analysis period. Space 2D had a single actual bill with start date of 4/ 16/ 2001 and 31 elapsed days. The user defined analysis period had an end date of 4/ 2001, which is equivalent to 4/ 30/ 2001. Since the actual bill was not completely inside the analysis period (it ended on 5/ 15/ 2001), it was not included in the calculations for this analysis period. Changing the analysis period end month from 4 to 6 will fix the problems and TREAT will perform the calculations.    Return to Top

Both Natural Gas and Electricity are checked in the Fuels Used in the baseload box, but it still won't let me enter in an estimated base load for the gas, and it still doesn't calculate the gas information.

TREAT does not allow you to enter estimated baseload because gas is not a heating fuel. The annual gas usage is not shown in the lower part of the screen due to a bug that will be fixed in the next version. For now, you may convert the value of calculated baseload Btu/ day/ SqFt for gas displayed in the center of the Analysis Periods screen to annual gas usage. Multiply it by heated area (181407 SqFt), by 365 days/ year (to convert to annual) and divide by 100000 (Btu/ Therm).    Return to Top

When I change the value of "Default Conditioned Area" on the General Billing Data screen, then re-calculate, fuel usage for the building does not change.

The conditioned area input on the billing screen is only used in billing calculations. To change the area of the building, you must change the input value for Floor Sq Ft on the Spaces screen.    Return to Top

How do I use TREAT on my VISTA machine?

For more detailed instructions on configuring VISTA for TREAT use, download our guide on VISTA compatability.
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