Service manual

Servicing should only be performed by a Qualified Service Agent

VF BOILER SERVICE MANUAL

START UP PROCEDURE (CONT)

Adjusting Manifold Gas

13. Set the boiler to Max Mode (Firing Modes - page 17). Check combustion readings using

combustion analyzer. Compare CO2 readings taken to the Max Mode CO2 table below.

If CO2 readings are not within this range adjust as follows:

Remove the flat, round, blue plastic cap from the top of the boiler’s 24 VAC gas valve.

Using a 3mm (7/64”) hex wrench, turn the high fire adjustment screw under the cap

counterclockwise to increase or clockwise to decrease gas flow and achieve the desired

CO2 level. Reinstall blue cap when adjustments are complete. CO readings should be

less than 200 ppm when firing in Max Mode.

14. Set the boiler to Min Mode (Firing Modes - page 17). Check combustion readings using

combustion analyzer. Compare CO2 readings taken to the Min Mode CO2 table below. If

CO2 readings are not within this range adjust as follows:

Remove the small metal slotted cap near the outlet of the boiler’s 24 VAC gas valve.

Using a TORX® T40 or a 5mm hex wrench turn the low fire adjustment screw under the

cap clockwise to increase or counterclockwise to decrease gas flow and achieve the

desired CO2 level. Reinstall the slotted cap when adjustments are complete. CO

readings should be less than 100 ppm when firing in Min Mode.

Start Up Note: Adjust the settings in small increments (no more than 1/16 turn) and allow

the combustion readings to stabilize for at least 3 minutes before readjusting. If required

CO2 levels on start up form differ from levels in this manual adjust to levels shown on start

up form.

Max Mode CO2 Levels

Min Mode CO

2 Levels

15. When start up procedure is complete return to the User Settings Menu and place the

boiler back into Mod Mode firing mode (Firing Modes - page 17). Adjust the Operating

Set Point in the User Settings Menu (page 8) to desired system temperature. Remove

all test instruments and replace all plugs and caps.

16. Review page 67. The boiler must have a throttling valve on the outlet line. The boiler

should have a bypass line with a throttling valve. Adjust the outlet valve to achieve a 20

- 40°F temperature rise through the boiler and the bypass valve to achieve a 120°F

minimum inlet water temperature. Make these adjustments at 100% firing rate.

NATURAL GAS 8.0 - 9.5% CO2 (CO < 200 PPM)

PROPANE GAS 9.5 - 10.5% CO

2 (CO < 200 PPM)

NATURAL GAS 6.5 - 7.5% CO

2 (CO < 100 PPM)

PROPANE GAS 7.5 - 8.5% CO

2 (CO < 100 PPM)