Carrier 58MVP instruction manual Step

NOT ENOUGH COOLING AIRFLOWÐGenerally, this indicates the Y/Y2 thermostat lead is not properly connected.

STEP	ACTION	YES	NO	GO TO
1.	Remove blower access panel and depress door switch. Use a piece of tape to hold switch closed.	Ð	Ð	2
	Wait a few sec for self test before proceeding to next step.
2.	Make sure thermostat is calling for cooling. If thermostat lead G is not connected, jumper across	Ð	Ð	3
	thermostat terminals R and G.
3.	Make sure thermostat fan control is in AUTO position if equipped.	Ð	Ð	4
4.	Do you have 24v across Y/Y2 and Com on furnace control board?	8	5	Ð
5.	You have a defective thermostat, or a break in wiring between thermostat and furnace, or the Y/Y2	Ð	Ð	6
	thermostat terminal is not wired to thermostat.
6.	Fix problem.	Ð	Ð	7
7.	Go to page number indicated in Index for CLEANUP AND START-UP INSTRUCTIONS.	Ð	Ð	INDEX
8.	Are air conditioning select switches A/C set to proper tonnage as required by condensing unit? (See	10	9	Ð
	Table 1.)
9.	Set air conditioning select switches A/C for proper tonnage as required by condensing unit. (See	Ð	Ð	7
	Table 1.)
10.	Disconnect the G thermostat lead or jumper if used.	Ð	Ð	11
11.	Does blower motor turn off in 90 sec when G thermostat lead is disconnected?	12	13	Ð
12.	Replace furnace control board.	Ð	Ð	7
13.	Observe operation of furnace in cooling mode for 8 minutes.	Ð	Ð	14
14.	Does furnace operate properly in cooling mode?	15	16	Ð
	Make sure outdoor unit is properly charged. If it is, go to page number indicated in Index for
15.	CLEANUP AND START-UP INSTRUCTIONS. If problem persists on an intermittent basis, replace	Ð	Ð	INDEX
	furnace control board. If problem still persists after replacing furnace control board, contact your dis-
	tributor.
16.	Does furnace abruptly go through a self-test sequence as blower comes up to speed?	17	24	Ð
17.	Do you have less than 17 vac between R and Com on furnace control board?	18	24	Ð
18.	Do you have less than 90 vac between P1 and P2 on furnace control board?	19	20	Ð
19.	Make sure the wire gage between main fuse box and furnace complies with wire size specification	Ð	Ð	6
	in Installation, Start-Up, and Operating Instructions.
20.	Disconnect the R thermostat lead.	Ð	Ð	21
21.	Do you have less than 17 vac between R and Com on furnace control board?	22	23	Ð
22.	Replace transformer.	Ð	Ð	7
23.	Check the thermostat wire gage between furnace and thermostat, and furnace and outdoor unit. It is
	recommended that AWG No. 18 color-coded copper thermostat wire be used for lengths up to 100	Ð	Ð	6
	ft. For wire lengths over 100 ft, use AWG No. 16 wire.
24.	Press down on microprocessor chip and make sure it is properly seated to furnace control board. If	Ð	Ð	6
	it is, replace furnace control board.

Table 1ÐAir Conditioning (A/C) Airflow Setup Switch Position

AIR CONDITIONER

AIRFLOW

A/C SWITCH POSITION

ALLOWABLE FURNACE MODEL SETUP

(TONS)

(CFM)

A/C-1

A/C-2

A/C-3

040

060

080

080

100

120

Default

1200 or

OFF

OFF

OFF

3 Tons

3 Tons

3 Tons

5

Tons

5

Tons

5

Tons

2000

1200 CFM

1200 CFM

1200 CFM

2000 CFM

2000 CFM

2000 CFM

1-1/2

600

ON

OFF

OFF

X

X

X

Ð

Ð

Ð

2

800

OFF

ON

OFF

X

X

X

X

X

X

2-1/2

1000

ON

ON

OFF

X

X

X

X

X

X

3

1200

OFF

OFF

ON

X

X

X

X

X

X

3-1/2

1400

ON

OFF

ON

X

X

X

X

X

X

4

1600

OFF

ON

ON

Ð

Ð

Ð

X

X

X

5

2000

ON

ON

ON

Ð

Ð

Ð

X

X

X

XÐIndicates allowable selection.

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