Hi
I know these 240's are getting old, but a site I was working at today still has 5 in active service and they are slowly replacing them. In the meantime one has developed a fault that I can't pin-point and it's irritating me as I normally find this model simple to diagnose and fix. In fact I generally prefer them to many newer ones!
Original symptoms - classic luke-warm hot water. I started off changing the diaphragm without really thinking much as it's dead easy on that model, and the old one was totally perished so it seemed fair enough.
However, this didn't solve it and I thought heating feed pipe was getting hot so suspected and changed the diverter valve. But still no hot water.
At this point I stopped and had a cup of tea. I then realised the heating had been on earlier, and in fact the heating feed pipe probably hadn't been hot due to the valve, so that change was probably not required and a red herring.
So then I stared feeling the pipes leading to the secondary heat exchanger. (Yes, should have done this first). The hot feed from the diverter to the heat exchanger was piping hot, as was the return. But the DHW pipe coming out of the HE wasn't getting hot at all.
The only thing I managed to achieve was that I found that if I restricted the mains cold water flow (using the isolater on the incomer) I could get the DHW pipe to be fairly hot, albeit with reduced but tolerable flow. So while not ideal, there is now at least some hot water.
It feels as if I've proved there is an issue with the secondary heat exchanger, but wanted to ask for collective wisdom before either tackling changing it or scrapping the boiler.
Thanks in advance.
I know these 240's are getting old, but a site I was working at today still has 5 in active service and they are slowly replacing them. In the meantime one has developed a fault that I can't pin-point and it's irritating me as I normally find this model simple to diagnose and fix. In fact I generally prefer them to many newer ones!
Original symptoms - classic luke-warm hot water. I started off changing the diaphragm without really thinking much as it's dead easy on that model, and the old one was totally perished so it seemed fair enough.
However, this didn't solve it and I thought heating feed pipe was getting hot so suspected and changed the diverter valve. But still no hot water.
At this point I stopped and had a cup of tea. I then realised the heating had been on earlier, and in fact the heating feed pipe probably hadn't been hot due to the valve, so that change was probably not required and a red herring.
So then I stared feeling the pipes leading to the secondary heat exchanger. (Yes, should have done this first). The hot feed from the diverter to the heat exchanger was piping hot, as was the return. But the DHW pipe coming out of the HE wasn't getting hot at all.
The only thing I managed to achieve was that I found that if I restricted the mains cold water flow (using the isolater on the incomer) I could get the DHW pipe to be fairly hot, albeit with reduced but tolerable flow. So while not ideal, there is now at least some hot water.
It feels as if I've proved there is an issue with the secondary heat exchanger, but wanted to ask for collective wisdom before either tackling changing it or scrapping the boiler.
Thanks in advance.
