Slant/Fin VGH-299-CH, Installation And Service Manual

Page: 86 / 128

E93.1601EN032.C VGH installation manual 86
13 TEMPERATURE PROTECTION
The difference between Supply temperature and Return Temperature is continuously monitored. A too big
difference can indicate a defective pump or a clogged heat exchanger. To protect the boiler, the burner controller
reduces the input when the temperature difference
∆ T becomes too high:
At maximum boiler input ∆ T is limited to 63 °F (35 °C) (Hx_Diff_DeltaT_Min).
In between 63 °F (35 °C) and 77 °F (43 °C) boiler input modulates between minimum and maximum.
At minimum boiler input ∆ T above 77 °F (43 °C) is allowed (Hx_Diff_DeltaT_Min plus 14 °F (+8 °C)).
Above ∆ T = 86 °F (48 °C), the boiler is switched OFF during HX_Diff_Max_Wait_Time.
Relevant factory set variables
Parameter Level
Factory Setting. Range
HX Diff DeltaT Min 3: Factory 63 ºF (35 ºC)
18….144 ºF (10 ….80 ºC)
HX Diff Max Wait Time
Wait time after upper limit primary heat exchanger differential has been exceeded.
3: Factory 180 Sec.
1….255 Sec.
14 ERROR INFORMATION.
Errors can be divided in three groups:
• Manual reset locking errors (can only be reset by the reset button).
• Blocking errors (will disappear when error is gone)
• Warnings (will disappear when the warning is gone, not stored in the
BCU )
The boiler circulator will continue to run during most locking and blocking error codes
. This is to prevent the
freezing of the Central Heating circuit when the boiler is in error during the winter period. For some non-volatile
lockouts the circulator will not be running, also see the error tables in this chapter for more details.
Boiler history.
The last 15 lockouts and 15 blocking errors are stored in the boiler control. This boiler history can be shown via the
Boiler History screen via the installer boiler status menu in one of the advanced displays.

Successful ignitions

Failed Ignitions

Flame Failures

Operation days

CH Burner Hours

DHW Burner Hours
Table 13. 1
Figure 13. 2
63
77
86
0
20
40
60
80
100
120
50 60 70 80 90 100
b
o
ile
r
in
put
[%
]
delta T [°F]
boiler input control
high power
low power
off