Honeywell Q539 Manuale Utente

Installation Instruction for the Trained Service Technician. 

Q539 Subbases provide cooling anticipators, and mounting for T87F Thermostats. Q539 Subbases also provide system 

and fan switching for heating, cooling, and heating-cooling thermostats. For subbase specifications, refer to Tables 1 and 2.

 TABLE 1—SUBBASE SPECIFICATIONS. 

Q539A provides system and fan switching and cooling 
anticipator for heating cooling systems. Includes indicator 
LOCKOUT LED for use in oil burner systems. 

HEAT -
OFF-
COOL 

AUTO-ON  RH

-

RC-W-Y-G-X 

3 

Q539H provides fan switching with Z terminal for low voltage 
fan switch to control fan in AUTO position. 

NONE 

AUTO-ON  R-W-Y-G-X-Z 

4 

Q539J provides system switching for control of heating and 
cooling for heat pump and electric heating. Auto fan operates 
through fan relay on both heating and cooling. 

HEAT -
OFF-
COOL 

AUTO-ON  R-W-Y-G-X-P-O-B 

5

 TABLE 2—TERMINAL DESIGNATIONS. 

R 

Transformer. 

RC

a 

Cooling Transformer. 

RH

b 

Heating Transformer. 

W 

Heating Relay or Valve Coil. 

Y 

Cooling Contactor Coil. 

B

c 

Heating Damper Motor or Changeover 
Valve (if used). 

O

d 

Cooling Damper Motor or Changeover 
Valve (if used). 

G 

Fan Relay Coil. 

X

e 

Clogged Filter Switch or Lockout Switch 
(primary control). 

P 

Heat Pump Contactor Coil. 

Z 

Q539H low voltage fan switch for control 
of fan relay in AUTO position for both 
heating and cooling control. 

a 

Cooling transformer in systems with separate heating and 
cooling circuits.

b 

Heating transformer in systems with isolated heating and 
cooling circuits. 

c 

Circuit only completed between R and B with system 
switch in HEAT position.

d 

Circuit only completed between R and O with system 
switch in COOL position. 

e 

Only available on subbases with indicator LEDs. 

M3375 

This control contains mercury in a sealed tube. Do not 

place control in the trash at the end of its useful life. 

If this control is replacing a control that contains mer­

cury in a sealed tube, do not place your old control in the 
trash. 

Contact your local waste management authority for 

instructions regarding recycling and the proper disposal of 
this control, or of an old control containing mercury in a 
sealed tube. 

1. Read these instructions carefully. Failure to follow 

instructions can damage product or cause a hazardous 

condition. 
2.  Check ratings given in instructions and on product to 

make sure product is suitable for your application. 

3.  Make sure installer is a trained, experienced service 

technician. 

4.  After completing installation check out product opera­

tion as provided in these instructions. 

Locate the subbase about 5 ft (1.5m) above the floor in 

an area with good air circulation at average temperature. 

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