Setup Test Mode

368262-UIM-B-1008

During normal operation, the furnace input rate can vary between 50% and 100% of full nameplate input, making it difficult to check for proper operation. To help with the furnace startup process, the control has a TEST MODE available that allows the furnace input rate to stay at a constant input rate. To access this TEST MODE perform the following sequence:

1.With power to the board on and with no thermostat calls (no call for heating, cooling or continuous fan), push and hold the TEST but- ton on the board for one second. The LED on the board will glow red.

2.Release the TEST button. The LED on the board will flash a rapid green signal, indicating that TEST MODE is activated.

3.Turn the thermostat to call for heat (R & W signal).

4.The furnace will light and operate at high (100%) firing rate. The furnace firing rate should be checked at this level to confirm that the furnace is not overfired or underfired.

5.To run the furnace at minimum rate (50%), press the ERROR but- ton once. The LED will flash one green flash to confirm.

6.To run the furnace at a middle rate (70%), press the ERROR but- ton twice within a five-second period. The LED will flash green two times to confirm.

7.To again operate the furnace at maximum (100%) rate, press the ERROR button three times within a five-second period. The LED will flash green three times to confirm.

8.If the thermostat call for heat is removed, the LED will flash a rapid green signal, indicating that the furnace is still in TEST MODE.

9.When startup tests are completed, turning off power to the board will take the furnace out of TEST MODE and will restore normal operation. The furnace will automatically return to normal opera- tion after 150 minutes if power is not cycled.

CALCULATING THE FURNACE INPUT (NATURAL GAS)

NOTE: Burner orifices are sized to provide proper input rate using natu- ral gas with a heating value of 1030 BTU/Ft3 (38.4 MJ/m3). If the heat- ing value of your gas is significantly different, it may be necessary to replace the orifices.

NOTE: DO NOT set manifold pressure less than 3.2 in wc or more than

3.8in wc for natural gas at sea level. If manifold pressure is outside this range, change main burner orifices.

DO NOT bottom out gas valve regulator adjusting screw. This can result in unregulated manifold pressure and result in excess over- fire and heat exchanger failures.

NOTE: If orifice hole appears damaged or it is suspected to have been redrilled, check orifice hole with a numbered drill bit of correct size. Never redrill an orifice. A burr-free and sqaurely aligned orifice hole is essential for proper flame characteristics.

Verify natural gas input rate by clocking meter.

1.Turn off all other gas appliances and pilots.

2.Run furnace for a minimum of 3 minutes in heating operation.

3.Measure time (in sec) for gas meter to complete 1 revolution and note reading. The 2 cubic feet dial provides a more accurate mea- surement of gas flow.

4.Refer to Table 10 for cubic feet of gas per hour.

5.Multiply cubic feet per hour by heating valve (BTU/cu ft) to obtain input.

If clocked rate does not match the input rate from the unit nameplate. follow steps in next section to adjust the manifold pressure. Repeat steps 2 - 5 until correct input is achieved.

Be sure to relight any gas appliances that were turned off at the start of this input check.

HIGH ALTITUDE NATURAL GAS ORIFICE CONVERSION

The National Fuel Gas Code requires that gas appliances installed above 2,000 feet elevation have their inputs de-rated by 4% per 1,000 feet above sea level. The modulating furnaces automatically de-rate for altitude by measuring the inducer blower pressure and using that to determine if there is adequate air to support good combustion. If there is not enough combustion air to properly support 100% of the furnace nameplate input rate, the control will reduce the input to the point that there will be good combustion.

Johnson Controls Unitary Products