Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS - Manual (Page 49)

Installation and Service Manual
49
Combustion Air Fans
Both the 500,000 - 750,000 Btu/hr models and the 990,000 -
2,070,000 Btu/hr models use a fan-assisted combustion
process. The 500,000 - 750,000 Btu/hr models have one fan
and the 990,000 - 2,070,000 Btu/hr models use two fans to
supply combustion air to the burners.
Fan Cleaning
Check each combustion air fan every six months. Clean the
fan as required when installed in a dusty or dirty location.
Oiling is not required.
Combustion Air Fan Adjustment
The combustion air fans are factory pre-set and should not
need adjustment in most cases. Follow the steps below to
adjust the fan if a continuous Low Air status code occurs.
Note: On the 500,000 - 750,000 Btu/hr models the air shutter
is adjusted on the side of the fan duct as depicted in Figure 52.
On the 990,000 - 2,070,000 Btu/hr models the air shutter is
adjusted on the rear of the fan duct as depicted in Figure 54.
1. Check for proper installation and draft in the venting
system. Correct as required.
2. The following pressure settings are for installations up to
4000 feet altitude. Contact the factory for high altitude air
pressure settings.
Adjusting Differential Air Pressure
The following is a recommended method for setting the
differential air pressure (
P) for each fan.
Figure 52 – Adjusting Air Shutter 500,000 - 750,000 Btu/hr
Figure 53 – Loosening Fan Transition Box Screws
Figure 54 – Adjusting Air Shutter 990,000 - 2,070,000
Btu/hr Models
Set-Up Procedure
Beside the fan duct is an air pressure switch with a large and a
small tube delivering pressure from points inside the pool
heater (see Figure 55). The pressure in the large tube is the
chamber pressure. The pressure in the small tube is the burner
pressure. They act together to make the pressure switch. By
disconnecting the caps from the tees in the pressure switch
hoses and connecting them to either side of a manometer, you
can read the differential pressure to the switch.
The left pressure tapping connection on the manometer
connects to the tee in the tubing from the pool heater front
chamber and the right pressure tapping connection on the
manometer connects to the tee in the small tubing from the
burner.
MO
RE AIR
LESS AIR
AIR SHUTTER