Hi there,
A friend has had a Viessmann Vitodens 100 boiler installed.
(open vented CH with pump & mid position valve & hwc in airing cupboard)
When CH is switched on the boiler fires up ok and hot water gets pumped via the 3 way valve into the CH circuit. - When the display on the front of the boiler reads between 51 and 55 degrees the boiler stops heating the water leaving cool water being pumped round the CH circuit.
5 minutes later when the displayed temp has dropped to about 29 degrees the boiler fires up again. - This continues to happen and the rads never get warm enough.
One boiler engineer that looked at it said the CH circuit needed balancing as the temp difference between flow & return pipes was too great, but the boiler does the same thing when only HW is selected so I'm not sure if he is right.
Does anyone have any ideas ?
thanks
A friend has had a Viessmann Vitodens 100 boiler installed.
(open vented CH with pump & mid position valve & hwc in airing cupboard)
When CH is switched on the boiler fires up ok and hot water gets pumped via the 3 way valve into the CH circuit. - When the display on the front of the boiler reads between 51 and 55 degrees the boiler stops heating the water leaving cool water being pumped round the CH circuit.
5 minutes later when the displayed temp has dropped to about 29 degrees the boiler fires up again. - This continues to happen and the rads never get warm enough.
One boiler engineer that looked at it said the CH circuit needed balancing as the temp difference between flow & return pipes was too great, but the boiler does the same thing when only HW is selected so I'm not sure if he is right.
Does anyone have any ideas ?
thanks