Hi,
I am having issues with my Baxi 105 HE (not the Instant model). There are two issues which may be related and hoping someone can advise on what this might be. I've read plenty of other threads for 'similar' issues which tend to point to the diverter potentially failing or requiring new diaphragm's in either the diverter or the DHW flow valve but none seem to fot the bill exactly here and doesn't make sense to me based on some of the tests I have done. Issues are...
1. DHW fluctuates in temperature in our upstairs bathroom and is most evident when using the shower
a) The boiler is located in our kitchen. Whenever using the hot tap in the kitchen, the boiler works fine and the water is constantly hot. Boiler fires up as expected and burns constantly until the DHW demand stops
b) Not the case upstairs for either our bathroom taps (less of a prob) or our thermostatic shower. Taps are usually hot all the time but can go cold sometimes. Shower no longer goes very hot and regularly has intermittent cycles of cold temperature. Flow of the shower itself doesn't appear to be that bad.. (certainly not much less than it used to be when was working ok). When looking at the boiler this weekend whilst the shower was on, the boiler would fire up, the burner burning towards maximum, then it would slowly reduce (i.e. the height of the flames physically getting smaller) until they eventually go out. This isn't the case for the downstairs tap which will slowly reduce but then maintain a minimal flame controlling the temperature.
2. The Central Heating works fine on its own and appears to fire up ok and warms all of the rads as expected. If the heating is on when there is a demand for DHW (from either upstairs or downstairs), as soon as the DHW demand stops, the heating seems to struggle. It will then keep igniting and resetting itself every few minutes. Will do this for anything up to 5-10 mins or so before eventually staying on. Throughout this process, the burner light will come on when the boiler ignites for around 5-6 seconds, then there seems to be the start of an increasing "whoosh" noise suggesting its increasing the gas to meet the demand but then that trips and the burner goes out. Process then repeats until the CH will eventually come back on.
So far, I've seen that both the upstairs/downstairs DHW demands will flick the DHW pressure switch at the front so that the burner ignites. This is the case for both the DHW pressure switch and also the one on the diverter at the back (which the manual says is the CH pressure switch but pretty sure was pushing switch on DHW demand also - is this right?).
Any help/confirmation anyone can give would be appreciated. If there are any tests I could do to at least get some indication of what the issue is before ordering parts that would also be very useful.
Thanks,
Jon
I am having issues with my Baxi 105 HE (not the Instant model). There are two issues which may be related and hoping someone can advise on what this might be. I've read plenty of other threads for 'similar' issues which tend to point to the diverter potentially failing or requiring new diaphragm's in either the diverter or the DHW flow valve but none seem to fot the bill exactly here and doesn't make sense to me based on some of the tests I have done. Issues are...
1. DHW fluctuates in temperature in our upstairs bathroom and is most evident when using the shower
a) The boiler is located in our kitchen. Whenever using the hot tap in the kitchen, the boiler works fine and the water is constantly hot. Boiler fires up as expected and burns constantly until the DHW demand stops
b) Not the case upstairs for either our bathroom taps (less of a prob) or our thermostatic shower. Taps are usually hot all the time but can go cold sometimes. Shower no longer goes very hot and regularly has intermittent cycles of cold temperature. Flow of the shower itself doesn't appear to be that bad.. (certainly not much less than it used to be when was working ok). When looking at the boiler this weekend whilst the shower was on, the boiler would fire up, the burner burning towards maximum, then it would slowly reduce (i.e. the height of the flames physically getting smaller) until they eventually go out. This isn't the case for the downstairs tap which will slowly reduce but then maintain a minimal flame controlling the temperature.
2. The Central Heating works fine on its own and appears to fire up ok and warms all of the rads as expected. If the heating is on when there is a demand for DHW (from either upstairs or downstairs), as soon as the DHW demand stops, the heating seems to struggle. It will then keep igniting and resetting itself every few minutes. Will do this for anything up to 5-10 mins or so before eventually staying on. Throughout this process, the burner light will come on when the boiler ignites for around 5-6 seconds, then there seems to be the start of an increasing "whoosh" noise suggesting its increasing the gas to meet the demand but then that trips and the burner goes out. Process then repeats until the CH will eventually come back on.
So far, I've seen that both the upstairs/downstairs DHW demands will flick the DHW pressure switch at the front so that the burner ignites. This is the case for both the DHW pressure switch and also the one on the diverter at the back (which the manual says is the CH pressure switch but pretty sure was pushing switch on DHW demand also - is this right?).
Any help/confirmation anyone can give would be appreciated. If there are any tests I could do to at least get some indication of what the issue is before ordering parts that would also be very useful.
Thanks,
Jon