Bryant 580F D. Heating, Units With Economizer+, Service, I. Cleaning, A. Evaporator Coil

Adjust the unoccupied minimum position to allow the mini- mum amount of outdoor air, as required by local codes, to enter the building. Make minimum position adjustments with at least 10 F (6 C) temperature difference between the outdoor and return air temperatures.

To determine the unoccupied minimum position setting, per- form the following procedure:

Calculate the appropriate supply-air temperature using the following formula: (TO x OA) + (TR x RA) = TM

TO = Outdoor-Air Temperature

OA = Percent of Outdoor Air

TR = Return-Air Temperature

RA = Percent of Return Air

TM = Supply-Air Temperature

As an example, if local codes require 10% outdoor air during occupied conditions, outdoor-air temperature is 60 F, and return-air temperature is 75 F:

(60 x 0.10) + (75 x 0.90) = 73.5 F

Carefully adjust the unoccupied minimum position until the measured supply-air temperature matches the calculated value. Then, carefully adjust the occupied minimum position set point on the controller until the desired position is reached.

D. Heating, Units With Economizer+

When the thermostat calls for heating, terminal W1 is ener- gized. The induced-draft motor is energized and the burner ignition sequence begins. The indoor (evaporator) fan motor (IFM) is energized 45 seconds after a flame is ignited. When additional heat is needed, W2 is energized and the high-fire solenoid on the main gas valve (MGV) is energized. When the thermostat is satisfied and W1 is deenergized, the IFM stops after a 45-second time-off delay. The economizer damper moves to the minimum position. When the thermo- stat is satisfied, the damper moves to the fully closed position.

SERVICE

CAUTION: When servicing unit, shut off all elec- trical power to unit and tag disconnect to avoid shock hazard or injury from rotating parts.

I. CLEANING

Inspect unit interior at the beginning of each heating and cooling season or more frequently as operating conditions require.

A. Evaporator Coil

Clean coil as required. Inspect coil at beginning of heating and cooling seasons.

1.Turn unit power off and install lockout tag. Remove evaporator coil access panel.

2.If economizer is installed, remove economizer by dis- connecting Molex plug and removing economizer mounting screws. Refer to Accessory Economizer Installation Instructions or Optional EconoMi$er+ section on page 18 for more details.

3.Remove filters from unit.

4.Clean coil using a commercial coil cleaner or dish- washer detergent in a pressurized spray canister. Wash both sides of coil and flush with clean water. For best results, back-flush toward return-air section to remove foreign material. Caution should be taken

as to not overflow the evaporator drain condensate pan.

5.Flush condensate pan after completion.

6.Reinstall economizer and filters.

7.Reconnect wiring.

8.Replace access panels.

B. Condenser Coil

Inspect coil monthly. Clean condenser coil annually, and as required by location and outdoor-air conditions.

One-Row Coils

Wash coil with commercial cleaner. Clean outer surfaces with a stiff brush in the normal manner. It is not necessary to remove top panel.

2-Row Coils

Clean coil as follows:

1.Turn off unit power and install lockout tag.

2.Remove top panel screws on condenser end of unit.

3.Remove condenser coil corner post. See Fig. 37. To hold top panel open, place coil corner post between top panel and center post. See Fig. 38.

4.Remove screws securing coil to center post.

5.Remove fastener holding coil sections together at return end of condenser coil. Carefully separate the outer coil section 3 to 4 in. from the inner coil section. See Fig. 39.

6.Use a water hose or other suitable equipment to flush down between the 2 coil sections to remove dirt and debris. Clean the outer surfaces with a stiff brush in the normal manner.

7.Secure inner and outer coil rows together with a field- supplied fastener.

8.Reposition the outer coil section and remove the coil corner post from between the top panel and center post.

9.Reinstall the coil corner post and replace all screws.

C. Condensate Drain

Check and clean each year at start of cooling season. In win- ter, keep drain dry or protect against freeze-up.

D. Filters

Clean or replace at start of each heating and cooling season, or more often if operating conditions require it. Replacement filters must be same dimensions as original filters.

Fig. 37 — Cleaning Condenser Coil

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