CleaverBrooks Hawk 1000, Руководство по эксплуатации

Страница: 72 / 82

Section 5 — Commissioning Hawk 1000
5-18 Part No. 750-366
5.12 Thermal Shock Routine
Steam boilers
Thermal shock protection is activated when actual water temperature is below 60% of the steam saturation
temperature at set point. Maximum limit for CV for PID is based on water temperature and is determined by
function. If boiler in thermal shock protection and release for modulation from FSG is true and water
temperature is above setting of hot standby off temperature*, thermal shock override timer is activated.
Thermal shock override timer is set for 126 seconds. Done bit of this timer resets the timer and increments
thermal shock override counter. Accumulated value of the counter is compared to the function generator
output and highest value is selected as maximum limit for CV. Every time thermal shock rung becomes true
output value from function generator is moved to the counter accumulated value. Thermal shock routine is
deactivated when hot water temperature reaches 90% of the saturated temperature at set point. It will not be
activated until temperature drops below 60% with fuel valve terminal de-energized. If fuel valve has been
de-energized for more than 8 hours, thermal shock protection is activated.
For Hot Water Boilers
Thermal shock protection is activated when actual water temperature is below minimum temperature (150F
for Firetube 120F for FLX) Maximum limit for CV for PID is based on water temperature and is determined by
function generator. If boiler is in thermal shock protection and release for modulation from FSG is true and
water temperature is above setting of hot standby off temperature*, thermal shock override timer is activated.
Thermal shock override timer is set for 60 seconds. Done bit of this timer resets the timer and increments
thermal shock override counter. Accumulated value of the counter is compared to the function generator
output and highest value is selected as maximum limit for CV. Every time thermal shock rung becomes true
output value from function generator is moved to the counter accumulated value. Thermal shock routine is
deactivated when hot water temperature reaches 90% of set point. It will not be activated until temperature
drops below minimum temperature with fuel valve terminal de-energized. If fuel valve has been de-energized
for more than 8 hours, thermal shock protection is activated.
*If fuel valve is energized for more than 1 hour (Steam) or 10 minutes (Hot Water) and water temperature is still below standby
temperature setting. Firing rate will start ramping up as described.