Crown TWZ065, Руководство по установке

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33
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.
c. using adjustment Mode
A list of parameters which can be changed on this control are shown in Table 12.5. 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) - Burner shuts down if the boiler water temperature exceeds this setting. The circulator will continue to
run. The high limit setting also serves as the water temperature set point (
SP
) during calls for both heat and DHW.
HdF
(High Limit Differential) - If the boiler shuts off on high limit, the water temperature must fall by an amount equal to the
differential during the same call for heat before the burner will again start. For example, with HL=180 and HdF=15, the burner
will shut off if the water temperature exceeds 180F and stay off until the temperature falls to 165F (180 - 15). Note that if all calls
for heat end while the burner is off on high limit, the burner will not restart during the next call for heat until the thermal purge
requirements described below are met.
On the Warm Start Boiler Control the High Limit Differential is fixed at 10F.
ZC
(ZC and ZR Terminal Functions - Cold Start Boiler Control) - Terminals ZC and ZR can be used to control a IWH circulator or
a second heating zone circulator using a 120VAC thermostat (see Section X). When ZC=dh, the L7248L assumes that an indirect
water heater circulator is connected to ZC and no thermal purge occurs upon a call for DHW before the boiler fires (see thermal
purge description below). In addition, a call for DHW will turn off the circulator connected to C1 and C2 if DHW priority (Pt) is
ON.
Setting ZC = Zr allows the second zone to be used as a heating zone. In this mode, there is no zone priority and a thermal purge
occurs regardless of whether the call for heat originates from T-T or ZR.
The use of the ZC=ELL (“External Low Limit”) is not recommended.
ZC
(ZC and ZR Terminal Functions - Warm Start Boiler Control) - Terminals ZC and ZR can be used to control a second heating
zone circulator or an IWH circulator using a 120VAC thermostat or be used to enable pumps in a warm start application (see
Section X). When ZC=dh, and DWH priority (Pt) is OFF, a second heating zone circulator can be connected to ZC and L2.
Though not recommended unless the tankless heater is removed from the boiler, setting ZC=dh and DWH priority (Pt) to ON,
allows an indirect water heater circulator with priority to be connected to ZC and L2.
Setting ZC = Zr energizes the ZC terminal while the boiler is warm. The T-T or ZR inputs are a call for heat that fires the boiler
unless the boiler water temperature falls below the Low Limit Set Point minus the Low Limit Differential in which case the
primary heating circulator connected to C1 and the ZC output are de-energized.