RA4.3                             HVAC Measures

RA4.3.1 Evaporatively-Cooled Condensing Units

To ensure reliable energy savings and proper operation and control, the evaporatively-cooled condensing unit shall conform to the requirements in section RA4.3.1.

The HERS verifications and eligibility testing 'listed in sections RA4.3.1.1 and RA4.3.1.2 shall be completed, certified by the HVAC installer on the Certificate of Installation, and verified by a HERS Rater on the Certificate of Verification.

The builder or installer shall provide a Certificate of Compliance that reports the use of an evaporatively-cooled condensing unit for determining performance standards compliance, that requires HERS verification of the system equipment, duct sealing, and refrigerant charge for compliance as described in Section RA4.3.1.1.

RA4.3.1.1    HERS Verification

The following shall be verified by a HERS rater and reported on a Certificate of Verification for the system:

(a)                                                                  EER at 95 o F dry bulb and 75 o F wet bulb temperature is 'listed with ARI (generally called EERa).

(b)    EER at 82 o F dry bulb and 65 o F wet bulb temperature is submitted to ARI and published by the manufacturer in accordance with ARI guidelines (generally called EERb).

(c)                                                          Presence of TXV is verified, if the ARI certified EERs are based on equipment with TXVs.

(d)      Ducts are tested and sealed in all installations of this equipment according to applicable requirements in Section RA3.1.

(e)      Proper refrigerant charge or presence of Fault Indicator Display (FID) is verified if compliance credit is taken for this measure when TXVs are not installed.

RA4.3.1.2    Eligibility Testing

The installing contractor shall complete the following eligibility testing and document the results on the applicable Certificate of Installation.

(a)      Verify that there is water in the water casing.

(b)      Switch on the cooling system by setting the thermostat below the room temperature.

(c)      Verify that the water pump starts running when the system is turned on.

(d)      When the water pump is running, verify that all the condenser coils are wet.

(e)      Verify that the high pressure trip for the compressor is set (per manufacturer’s specifications) at or below 300 psig for R22 Refrigerant and at or below the saturation pressure corresponding to a temperature of 1310 F for all other refrigerants.

(f)       Turn off the water supply to the water casing, drain the water from the sump, and verify that the water pump and the compressor trip.

(g)      Verify that the condenser coils have a corrosion resistant coating and that the water casing is made up of corrosion resistant material.

(h)      Verify that the electrolytic protection is installed.

(i)       Verify that a blow-down pump is installed for periodic blow-down to remove solids from the water casing.

(j)       Verify that the operation of this pump is automatic based on compressor run time or the conductivity of the water in the casing.

(k)      Verify that the water casing is sloped downward towards the blow-down pump location to facilitate removal of solids.

(l)       Drift eliminators must be installed to reduce the loss of water to less than 0.002% of the recirculated water (as per test method CTI-HBIK Std.140.0 or other approved procedure).

(m)     Condensate water must be routed to the evaporative condenser sump, unless it is not practical i.e. the fan coil and condenser not separated by conditioned space.

(n)      Condenser must have a certification from the manufacturer that water consumption is less than .15 gph per ton of capacity

(o)      Water connection is made with tubing no large than ¼ inch diameter

(p)      Overflow from the unit is not connected directly to the sewer drain ( son in the event of a water float failure an overflow condition can be more easily detected) or another means of determining an overflows condition is provided.

(q)      The system has a backup solenoid water shutoff control or no spill sump.

RA4.3.2 Evaporative Cooling

Qualifying equipment is limited to either indirect-direct or indirect evaporative coolers.  Direct evaporative coolers and indirect or indirect-direct evaporative coolers that do not meet the following eligibility criteria shall not be used.

RA4.3.2.1    Eligibility Testing

The installing contractor shall complete the following eligibility testing and document the results on the applicable Certificate of Installation.

(a)  Eligible equipment shall be 'listed under Title 20 Appliance Standards.


(b)  The equipment manufacturer shall certify to the Commission that water use does not exceed 7.5 gallons per ton hour based on the Title 20 Appliance Standards testing criteria.


(c)  Equipment shall be permanently installed (no window or portable units).


(d)  Installation shall provide for automatic relief of supply air from the house with maximum air velocity through the relief dampers not exceeding 800 fpm (at the Title 20 rated airflow). Pressure relief dampers and ductwork shall be distributed to provide adequate airflow through all habitable rooms. For installations with an attic, ceiling dampers shall be installed to relieve air into the attic, and then to outside through attic vents. For installations without an attic, sidewall relief dampers are acceptable.


(e)  To minimize water consumption, bleed systems shall not be allowed.


(f)   A water quality management system (either “pump out” or conductivity sensor) is required. “Pump out” systems can either be integral to the evaporative cooler or they can be accessories that operate on a timed interval.  The time interval between dumps shall be set to a minimum of six hours of cooler operation. Longer intervals are encouraged if local water quality allows.