Hi guys
Have had the boiler installed for 6 years, and been problem free until now.
When demand for DHW is called for, the boiler fires up as per normal, and delivers some hot water, but after a short period the boiler shutsdown with unheated water being delivered. This cycles on and off every 30 seconds or so. A bath is therefore a non event as the fill can never be hot enough. i have wound back the DHW temp control and this seems to help, but only a little.
Also, when a heat demand is placed on the central heating, the boiler fires up as required, but cuts out before the desired temperature is reached. It then cycles for a time until the set temp is reached with 3 minutes dwell time between firing up. I have read in the manual that when the primary thermistor see's 6 degrees above the set temperature that it will shut down the boil and instigate a 3 minute anti cycle. After three mins the boiler will fire again if temp has dropped. So the three minute delay makes sense, but why is it overheating, limescale?
I am led to believe by others that the issue could be either heat exchanger / diverter valve / thermistor related.
Any ideas on what to tackle first?
I am an electrical engineer so can check operation of the thermistor (I guess)!!
Currently running some F3 through the system before draining down and refilling with water + F1. Now would be the time i guess to pull out the secondary heat exchanger (DHW) for a flush.
Have had the boiler installed for 6 years, and been problem free until now.
When demand for DHW is called for, the boiler fires up as per normal, and delivers some hot water, but after a short period the boiler shutsdown with unheated water being delivered. This cycles on and off every 30 seconds or so. A bath is therefore a non event as the fill can never be hot enough. i have wound back the DHW temp control and this seems to help, but only a little.
Also, when a heat demand is placed on the central heating, the boiler fires up as required, but cuts out before the desired temperature is reached. It then cycles for a time until the set temp is reached with 3 minutes dwell time between firing up. I have read in the manual that when the primary thermistor see's 6 degrees above the set temperature that it will shut down the boil and instigate a 3 minute anti cycle. After three mins the boiler will fire again if temp has dropped. So the three minute delay makes sense, but why is it overheating, limescale?
I am led to believe by others that the issue could be either heat exchanger / diverter valve / thermistor related.
Any ideas on what to tackle first?
I am an electrical engineer so can check operation of the thermistor (I guess)!!
Currently running some F3 through the system before draining down and refilling with water + F1. Now would be the time i guess to pull out the secondary heat exchanger (DHW) for a flush.