V
vhooda
Hi, my 6 yr old firbird combi has had a new heat exchanger 6 months back and had to change the flow switch 6 weeks back when it burst and started leaking water. All was well untill I started putting CH on last week. Once the CH has come on the boiler firing sequence seems to get disturbed even if there is no CH but the switch is in on position (its got a manual 24hr timer and it only comes on in the night for couple of hrs.)
Normally, once I open a DHW tap the fan starts almost straight away follwed by burner within 30 secs. If the CH has been on in the night the firing sequence does not happen in morning, there is a audible click when I turn the tap on followed by fan after about 2 mins or so (later then usual) and that continues untill the hot water starts turning lukewarm. The burner does eventually come on after 5 mins or so but then it cannot make up for the lost time and I have to close the tap for about 5 mins before it builds up it store and turns hot again.
If however, I turn the central heating off and restart the boiler it returns to its normal firing sequence untill CH is turned on at some point.
Also I have noticed the CH can turn luke warm when the burner is not firing along with the DHW i.e if dhw and ch are on at the same time.
Only thing I can remember is that when the flow switch started leaking water it made all the wirings in the control box wet and I had to dry out everything before restarting 6 weeks back.
Another thing, there is a small drip of kerosene ( 1 drop in 6 seconds) from somewhere around the burner, it seems to be dripping from the pump. Also I am not sure how much you should read into my correlation of CH switch in on position and change in firing sequence. I can see that sometimes just by switching the boliler off and restarting seems to correct the sequence. But it only gets screwed again only when the CH has come on.
Normally, once I open a DHW tap the fan starts almost straight away follwed by burner within 30 secs. If the CH has been on in the night the firing sequence does not happen in morning, there is a audible click when I turn the tap on followed by fan after about 2 mins or so (later then usual) and that continues untill the hot water starts turning lukewarm. The burner does eventually come on after 5 mins or so but then it cannot make up for the lost time and I have to close the tap for about 5 mins before it builds up it store and turns hot again.
If however, I turn the central heating off and restart the boiler it returns to its normal firing sequence untill CH is turned on at some point.
Also I have noticed the CH can turn luke warm when the burner is not firing along with the DHW i.e if dhw and ch are on at the same time.
Only thing I can remember is that when the flow switch started leaking water it made all the wirings in the control box wet and I had to dry out everything before restarting 6 weeks back.
Another thing, there is a small drip of kerosene ( 1 drop in 6 seconds) from somewhere around the burner, it seems to be dripping from the pump. Also I am not sure how much you should read into my correlation of CH switch in on position and change in firing sequence. I can see that sometimes just by switching the boliler off and restarting seems to correct the sequence. But it only gets screwed again only when the CH has come on.
