York W)036 THRU 060 Specifications download pdf (Page 45)

542300-YIM-A-1009

Johnson Controls Unitary Products 45

Electric Heat Anticipator Setpoints

It is important that the anticipator setpoint be correct. Too high

of a setting will result in longer heat cycles and a greater

temperature swing in the conditioned space. Reducing the

value below the correct setpoint will give shorter “ON” cycles

and may result in the lowering of the temperature within the

conditioned space. Refer to Table 20 for the required electric

heat anticipator setting.

Gas Heating Sequence Of Operations

When there is a W1 call for heat, the heat relay (RW1) is

energized by the unit control board (UCB). The RW1-1 contacts

immediately close energizing the ignition control board (ICB).

The ICB checks the state of the flame sense circuit, the roll out

switch, the centrifugal switch and the primary / auxiliary

temperature limit switch circuit. If they are in the expected state,

then the ICB energizes the draft motor and verifies that the

centrifugal switch located on the end of the draft motor closes.

After the centrifugal switch closes, a 15 second heat exchanger

purging period is completed. After this purging period, the ICB

will simultaneously energize the pilot gas valve and the ignition

coil. Once the flame sensor senses a pilot flame is present, the

ignition coil is de-energized. The ICB checks for pilot flame

stability and once the ICB is satisfied that the pilot flame is

stable, the main gas valve is energized by the ICB. The UCB

will energize the indoor blower after a 45 second delay from the

call for heat. The ICB and UCB both monitor the furnace safety

devices during the furnace operation. When the call for heat is

satisfied, the ICB closes the pilot and main gas valves and

performs a 30 second purging of the heat exchanger by

continuing the operation of the draft motor. The UCB continues

the operation of the indoor blower for a configurable amount of

time after the call for heat is satisfied.

Figure 22: Gas Valve Piping

Two Stage Furnace Only

If a W1 only call for heat from a two stage thermostat is present,

then a two stage furnace will start on high fire for 1 minute and

then reduce to low fire until the call for heat is satisfied or a W2

call for heat is received. If a W2 call for heat is received while in

low fire operation, then the ICB will immediately move to high

fire operation. If a W1 and W2 call for heat is present, then the

furnace will remain on high fire operation until the W2 call for

heat is satisfied.

Automatic staging of a two stage furnace using a single stage

thermostat is possible. To achieve automatic staging of a two

stage furnace using a single stage thermostat, a jumper is

installed between R and W2 on the UCB with the single stage

thermostat heat control connected to W1. Wired in this manner,

the ICB will interpret the continuous power on W2 as automatic

two stage operation of the two stage furnace. The unit will

operate the same as a W1 only call for heat for 10 minutes. If

the call for heat is not satisfied in the 10 minutes, then the ICB

will move to high fire operation until the W1 call for heat has

been satisfied.

Gas Heat Operation Errors

During furnace operation, the ICB monitors the flame sense

circuit, the centrifugal switch, the primary limit switch and the

roll out switch. If a signal from any of the inputs moves to a fault

state, then the ICB immediately closes the pilot and main gas

valves. The ICB will determine the device that is signaling a

fault and flash a code for that device. A primary limit trip,

centrifugal switch trip or flame sense fault triggers a temporary

lock out. An auxiliary limit or a roll out switch trip requires

intervention to reset the ICB. The UCB also monitors the

primary limit and gas valve.

Temperature Limits

The primary limit is located such that the temperature

sensitive switch can sense the temperature of the heat

exchanger tubes. On single stage models the limit is mounted

to the condenser partition panel. On two stage models the limit

is mounted just above the inlet of the heat exchanger tubes on

the right side. If a primary limit (LS) fault occurs (the primary

limit opens due to excessive heat exchanger temperature),

then the ICB will flash the appropriate code (Table 26) and

monitor the primary limit. The UCB will energize the indoor

blower and the ICB will energize the draft motor while the

primary limit is open. When the primary limit closes and the

call for heat still exists, the ICB will start the ignition sequence

Table 20: Electric Heat Anticipator Setpoints

Heater

Voltage

Setting, Amps

TH1 TH2

230-3-60

0.35 -

70.35-

10 0.35 -

15 0.35 0.19

20 0.35 0.38

30 0.35 0.38

460-3-60

0.35 -

10 0.35 -

15 0.35 -

20 0.37 0.29

30 0.37 0.29

575-3-60

0.35 -

15 0.35 -

20 0.37 0.29

30 0.37 0.29

Gas Valve

Gas main

Main valve

To main burner

Redundant valve

To pilot burner

1 2 ... 40 41 42 43 44 45 46 47 48 49 50 ... 57 58

Comments to this Manuals

No comments

York W)036 THRU 060 Specifications Page 45

Comments to this Manuals

Related products and manuals for Heat pumps York W)036 THRU 060