Crown Aruba 5 Installation Manual

WARNING

Improper adjustments to control parameters could result in unreliable boiler

operation, property damage, personal injury, or loss of life. Adjustments should

only be made by a qualified heating technician.

A list of parameters which can be changed on this control are shown in Table 11.5. To enter Adjustment mode and change

parameters:

1) Press and hold I, ↑, ↓ together for at least 3 seconds.

2) Use I to advance to the parameter which is to be changed.

3) Use the ↑ or ↓ buttons to change the setting or select from possible choices. See below for additional information on

the use of these parameters.

4) If other parameters are to be changed, use the I button to advance to the next parameter needing adjustment and change it

in the same way.

5) After all parameters have been changed, use the I button to advance until bAc is shown on the display.

6) Press either the ↑ or ↓ key to return to Status mode. Alternatively, the control will return to Status mode if no key is

touched for 5 minutes.

HL (High limit Set point) - Burners shut down if the boiler water temperature exceeds this setting. The circulator will continue

to run. Unless the Crown outdoor reset card is installed, the high limit setting also serves as the water temperature set point (SP)

during calls for both heat and DHW.

dF (High limit dierential) - If the boiler shuts o on high limit, the water temperature must fall by an amount equal to the

dierential during the same call for heat before the burners will again start. For example, with HL=180 and dF=15, the burners

will shut o if the water temperature exceeds 180F and stay o until the temperature falls to 165F (180 - 15). Note that if all calls

for heat end while the burners are o on high limit, the burner will not restart during the next call for heat until the thermal purge

requirements described below are met.

Or (Circulator Overrun) - Determines how long the Heating Circulator will operate after the call for heat ends. In some cases, this

can help reduce energy consumption by sending heat stored in the boiler out into the system. At the same time, caution should

be exercised before setting this value to something other than zero. Before doing so, verify that the system will permit ow (e.g.

ow is not completely cut-o by closed zone valves) and that the overrun will not cause overheating problems.

Circulator overrun is only possible on the heating zone. The DHW Circulator will not over-run, even if the DHW zone is used

as a second heating zone.

PP (Thermal Purge Time) - Upon a call for heat, the boiler will prevent burner operation until either:

• The water temperature drops below the Thermal Purge start temperature (St) OR:

• The thermal purge time has passed

For some examples of this operation, see Table 11.6. If the “DHW” zone is used for space heating (dh=tt2), this thermal purge

function will also keep the burner o at the beginning of a call from the thermostat connected to the “DHW” terminals in the

manner described above. If the “DHW” zone is being used for DHW (dh=dh), the burners will immediately come on upon a call

for DHW as long as the water temperature is below the high limit setting.

Thermal purge is only invoked when a call for heat rst appears and the boiler is not already ring. For this reason, if the boiler

is already ring in response to an call for heat, and a call for heat appears at the second zone, the boiler will continue to re.

St (Thermal Purge Start Temperature) - See description for Thermal Purge Time above.

C. Using Adjustment Mode