SECTION C: Installation
To make an adjustment to a setting in the control, begin by selecting the “ADJUST” menu. To change from the view menu to the adjust menu, simultaneously press and hold all three buttons for 1 second. The menu name, “ADJUST” will be displayed in the menu field.
The menu will automatically revert back to the view menu after 20 seconds of keyboard inactivity. Then scroll to the desired item using the scroll button. Fi- nally, use the ▲or ▼ button to make the adjustment.
In the absence of other information, the values pro- vided in Table N should be used as default settings.
Heater Sequence of Operation
Model 503 - 1503
1.The black (hot) wire lead, located at the right- middle front inside the control compartment, goes directly to the main power switch.
2.When the main power switch is placed in the “ON” position, the 120 VAC terminal block in the control compartment, the N.O. contacts of pump relay, the N.O. contacts of blower relay, the 120/24 VAC transformer, and terminals L1 and F1 of the ignition module are powered.
3.The 120/24 VAC transformer sends a 24 VAC hot power signal to the 24V Terminal Block .
4.24 VAC is sent from the 24V Terminal Block to the NO pump contacts on the modulating tempera- ture control (pin #13), to pin TP2 of the optional alarm relay, to terminal R of the alarm circuit on the modulating temperature control (pin #24) and the green “Power On” LED on the front of the heater will illuminate.
5.24 VAC power is sent from 24V Terminal Block to Pin
24 VAC is sent from the NC contacts of the man- ual high limit to pin
Upon loss of water in the heater, the Low Water Cut Off (if equipped) will send a 24 VAC signal to pin
6.A 24 VAC signal is sent from the NO contacts of the Low Water Cut Off to the common terminal of the Blocked Vent Switch.
During a blocked vent condition a 24 VAC signal is sent from the NO open contacts of the Blocked Vent Switch to pin
7.During normal operation of the heater the 24 VAC signal exits the NC contacts of the Blocked Vent Switch and is sent to the common terminal, of the Low Gas Pressure Switch (if equipped).
During a low gas pressure condition 24 VAC is sent from the NC contacts of the Low Gas Pres- sure Switch to pin
8.24 VAC is sent from the NO contacts of the Low Gas Pressure Switch to the common terminal of the High Gas Pressure Switch (if equipped).
During a high gas pressure condition 24 VAC is sent from the NO contacts of the High Gas Pres- sure Switch to pin
9.24 VAC is sent from the NC contacts of the High Gas Pressure Switch to the common terminal of the Auto Reset High Limit (if equipped) and to en- ergize the coil of optional alarm relay.
If the Auto Hi Limit opens, 24 VAC is sent from the NO contacts of the Auto Hi Limit to pin
10.24 VAC is sent from the NC contacts of the Auto Reset Hi Limit to the common terminal of time de- lay relay.
11.24 VAC is sent from the NC contacts of time delay relay to the common terminal of the burner switch located on the front exterior panel of the heater.
12.Power then travels to the enable/disable connec- tion and to the Ht D (heat demand) connection of the modulating temperature control.
Power splits from the enable/disable and goes to the stage contact of the modulating temperature control (pin #15).
13.When the stage contact closes on the modulating temperature control, 24 VAC is sent to the com- mon terminal of the flow switch and to pin
31
