Hydraulic Components - Honeywell SDC Service Manual

Hydraulic Components

7.1.1
Function
128
7 Hydraulic Components
7.1 Heat generator: Boiler
Heat generator start-up protection
The start-up protection function prevents condensate building up
when heating up while cold.
There are three different modes of start-up protection that can be
set:
Unlimited start-up protection
When the temperature in the heat generator drops to 2 K below
the set minimal limit, all heating circuits are separated, at the
water side, from the heat generator (pumps = off, mixed heating
circuit = closed) to pass through the dew point as quickly as
possible. The heating circuits are enabled as soon as the
temperature in the heat generator has reached the minimum limit
plus half of the burner switching differential 1.
Start-up protection controlled by weather conditions
The heating-up characteristic is the same as for unlimited start-up
protection, meaning the heat generator remains in operation until
the set minimum temperature plus half of burner switching
differential 1 is exceeded. Below the minimum temperature, the
pumps remain switched off and the mixed heating circuit closed.
Once the heat generator has been switched off, the start-up
protection becomes active again only when the heat generator
temperature drops below the weather-responsive demand value
(acc. to heating curve setting and nominal room setting). The
subsequent heating-up follows the same scheme as for unlimited
start-up protection. The result is a mean value based on the
difference between the weather condition-controlled demand
value and the minimum limit setting. This mean value will be
significantly lower than the value set for a heat generator
operated with a permanent minimum temperature limit.
SDC / DHC
EN2H-0221GE51 R0812