Can a hayward heater combustion blower idxlbwr1930 be used in place of a idxbwr1930 blower.

The Hayward H Series Pool Heater with standing pilot uses a standing flame to safety initiate combustion, and the standing pilot flame is uses to generate about 0.400 to 0.450 volts DC to operate the gas valve.

CAUTION: Your Hayward H Series Pool Heater is essentially a furnace. Only qualified technicians with proper training and tools should repair your heater.

Once you have completed the pilot start procedure in your heater manual, the pilot flame should be visible but it is difficult to see. The pilot is located at the bottom of the heater, to the left side of the burner chamber, about half way between the front and back of the heater. Before attempting to verify the pilot, it's wise to turn the thermostat to the full counterclockwise OFF position. There are two useful methods to verify the pilot: 1) Before you initiate the pilot procedure, place a small mirror on the floor of the heater on the left side of the burner chamber, just inside the combustion area. CAUTION: DO NOT attempt to place or remove this mirror while the heater is in combustion mode! After placing the mirror, you should be able to see the pilot assembly. Follow your pilot start procedure, then you should be able to see the pilot flame in the mirror before you turn the gas valve knob into the ON mode. Be careful to remove the mirror before initiating combustion. 2) Only when the pilot flame is on will the thermocouple generate the circuit voltage required to operate the gas valve. During the pilot start procedure, while the gas valve knob is still in the "pilot" position and the pilot flame is on, the circuit voltage can be measured at the gas valve without danger of initiating combustion. Using a volt meter, measure the voltage between the RED and WHT wires on the gas valve terminals. This measurement should be between 0.400 and 0.450 volts DC. If below, the gas valve will not operate even if the pilot is ON.

After verifying the pilot, be sure to remove the mirror (if used) and the voltmeter (if used), turn the gas valve to "ON", and return the front heater cover before initiating combustion.

It will not run with AO code. That is telling you something is wrong/blocking the combustion fan from satisfying the safety switch. If it is a brand new heater this usually means the correct voltage has not been set in the heater = you would need to check what you have and then check setting. Doing this incorrectly could completely destroy all electronics in the heater.
If this is a heater startup for a new season the rubber tube from the combustion fan to the blower switch could be off or damage by rodent bites.
If this heater is older it could be a clogged heat exchanger which is a much bigger repair or problem for a homeowner.
manuals are available on haywardpool.com

gas valve coils are shot

This tube connects between the blower and a vacuum or pressure switch. If the tube is broken the switch can't detect whether the blower is working. If you fix the tube then the system will continue its sequence and if it finds no more faults it should ignite and the heater can heat.

It sounds like your pool heater is not firing. I would check several things: the burner might be blocked and clogged, the gas valve might need to be replaced, the direct spark module might be malfunctioning, or the combustion blower might be cleaned. One of these is probably the issue. A service man can repair all of these problems.

You didn't indicate exatctly which model you have. But on most the AO error code is :Blower vacuum switch
open error If the blower prover switch does not close after the blower starts the control will
stop the ignition trial go into lockout. The blower will continue to run. Automatic reset is immediate after the switch closes.Check to be sure combustion blower starts
If you don't have your manual you can download one for your exact model at : www.haywardnet.com

It sounds like it might be your gas pressure. Test the gas pressure. If it is not correct, you might need to either have the burner or combustion blower cleaner or you might need to have your gas valve replaced. This maintenance will need to be performed by some one certified to work on pool heaters.

AO will apply to your blower, blower tubing, or blower vacuum switch. You need to check these items.

sounds like a flame sensor.remove ignitor assembly and clean with fine emory cloth or steel wool.when properly cleaned it should feel smooth for entire length of sensor