Hi,
A friend of mine has an Ideal Isar boiler which has been installed for 12 years. His central heating has been playing up recently, it needs filling on a regular basis as one of the rads is leaking (I'll try and tackle this later). However his hot water has now stopped working completely.
If you turn on the hot water tap it flows at good pressure, the boiler spools up, and then about 10 seconds later the boiler shuts down with 'H A' flashing on the display. Occasionally the water temperature will increase slightly but nothing like what it should be. From what I understand this is an overheating error message. Googling has led me to believe this is likely to be a blocked DHW heat exchanger. I don't think it'll be a stuck diverter valve as the radiators don't get warm when hot water is ran. One other thing to note is the water pressure needle flitters between 1.2 and 1.5 bar when the HW is first turned on, I assume this would be because the water pressure is increasing as it boils.
So my questions are do you think my diagnosis is correct, and if so is it legal for an average Joe (not gas safe) like me to attempt to replace the DHW exchanger? I've read that this area of the boiler is outside of the sealed combustion chamber and as such isn't governed by the usual gas safe rules but would like some clarification on this first.
Your help and advise is appreciated
A friend of mine has an Ideal Isar boiler which has been installed for 12 years. His central heating has been playing up recently, it needs filling on a regular basis as one of the rads is leaking (I'll try and tackle this later). However his hot water has now stopped working completely.
If you turn on the hot water tap it flows at good pressure, the boiler spools up, and then about 10 seconds later the boiler shuts down with 'H A' flashing on the display. Occasionally the water temperature will increase slightly but nothing like what it should be. From what I understand this is an overheating error message. Googling has led me to believe this is likely to be a blocked DHW heat exchanger. I don't think it'll be a stuck diverter valve as the radiators don't get warm when hot water is ran. One other thing to note is the water pressure needle flitters between 1.2 and 1.5 bar when the HW is first turned on, I assume this would be because the water pressure is increasing as it boils.
So my questions are do you think my diagnosis is correct, and if so is it legal for an average Joe (not gas safe) like me to attempt to replace the DHW exchanger? I've read that this area of the boiler is outside of the sealed combustion chamber and as such isn't governed by the usual gas safe rules but would like some clarification on this first.
Your help and advise is appreciated
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