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Jason Whatley
Jason Whatley, HVAC/R Supervisor
Category: Pool and Spa
Satisfied Customers: 60
Experience:  HVAC/R Supervisor at DOJ
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My Laars heater isn't turning on. Airflow sensor

Customer Question

My Laars heater isn't turning on. Airflow sensor
Submitted: 2 years ago.
Category: Pool and Spa
Customer: replied 2 years ago.
I have blown out the exhaust with air, have physically checked to make sure all of the wires are connected. The flow from the pool pump is good and there is enough water in the pool for correct flow. The low fan starts but usually the high fan kicks on to ignite the gas but that's not happening. It sits on the low fan setting for a few minutes and then triggers the air flow sensor and needs servicing. The unit is 12 years old but in great shape (southern california. It was working a few days ago and just stopped.
Expert:  Jason Whatley replied 2 years ago.
Hello, my name is ***** ***** I'm an expert here. I'm here to try and help you out with your heating issue! Can you provide me with the model number for your Laars heater?
Customer: replied 2 years ago.
Laars LT
Expert:  Jason Whatley replied 2 years ago.
Very good. The pressure switch is trying to verify proper exhaust flow before firing and it's not, hence why it's only running the fan for a bit before its shutting off on failure. Attached is a link to the manual (if you don't have it). Page 21 will lead you to things to check for an air switch failure. Look to make sure the port where the pressure switch tubing attaches to the blower housing. Remove the tubing from this port, as well as from the pressure switch itself. Blow through the tubing and ensure there is no blockage in the tubing. Take a paper clip or similar "tool" and insert into the port to ensure there is no debris blocking the port. Ensure that there is no blockage in the exhaust or intake ducting (bees nest, birds nest, anything that can block the flow). Confirm you have proper voltage to the fan motor if you have a volt meter. Confirm the pressure switch tubing isn't cracked, split, dry rotted etc... It should be plyable and not pinched off. Also ensure the wiring connections are tight and secure to the pressure switch.