Buderus 500 - 28/C Servicing Manual page 25

Diagnosis
box 23
Check to ensure that the preset room temperature or heating configuration of the Buderus controls or ON/
step 2
OFF controller has been adjusted to a high enough setting (see operating instructions).
Is the preset room temperature or heating configuration of the Buderus controls or ON/OFF controller
step 3
adjusted to a high enough setting?
Adjust the preset room temperature controller or heating configuration of the Buderus controls or
step 4
ON/OFF controller to a higher setting (see operating instructions).
Check to see if the "heating requirement" (K) indicator lights up on the display, see box 11.
step 5
Does the "heating requirement" (K) indicator light up?
step 6
Check the Buderus controls or ON/OFF controller as per box 177.
step 7
Is the Buderus controls or ON/OFF controller working correctly?
step 8
Replace the thermostat cable.
step 9
Replace the Buderus controls or ON/OFF controller.
step 10
Check to ensure that the CH flow temperature at the DBA control panel or on the Buderus controls or ON/
step 11
OFF controller is adjusted to a high enough setting as per box 14 and box 61 .
Is the CH flow temperature adjusted to a high enough setting?
step 12
Are enough thermostatic valves open on the radiators, convectors, etc?
step 13
Open more thermostatic valves on the radiators, convectors, etc.
step 14
Adjust the CH flow temperature as per box 14 and box 61. Ensure that the Buderus controls or
step 15
ON/OFF controller are calling for a heating demand.
Check to ensure that the CH flow temperature is correctly adjusted, see box 14.
step 16
Is the CH flow temperature adjusted to a high enough setting?
step 17
Adjust the CH flow temperature to a higher setting, see box 14.
step 18
Is the CH flow temperature of the boiler sufficient to heat the building?
step 19
Install a larger boiler.
step 20
Is there a hot water supply?
step 21
Is an internal 3-way valve fitted?
step 22
Check the movement of the servomotor of the internal 3-way valve, see box 181.
step 23
Does the servomotor of the internal 3-way valve move correctly?
step 24
Check the drive mechanism of the internal 3-way valve, see box 195.
step 25
Is the drive mechanism working correctly?
step 26
Replace the drive mechanism of the internal 3-way valve, see box 198.
step 27
Check the actuation of the servomotor of the internal 3-way valve, see box 185.
step 28
Does the servomotor of the internal 3-way valve start up correctly?
step 29
We reserve the right to make technical modifications
Servicing manual Gas condensing boiler Buderus 500-24/S, 500-24/C and 500-28/C • Issued 02/2006
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Buderus Ltd. • http://www.buderus-domestic.co.uk
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