Hello all,
I've just got my new Grant Combi 70 oil fired boiler up and running (passed BCO inspection and has been commissioned).
A similar problem to mine was listed last week withou any replies so maybe no one knws the answer but here goes.
I'm having problems with the domestic hot water side, heating is OK. The DHW is coming out milky with dissolved air but is hot initialy (after cold in pipes has been pushed through). The pressure then drops dramatically to almost a trickle and the water is luke warm. Pressure then picks up a bit when I open the taps further but not full mains pressure. This happens with the boiler thermostat at all settings, including full on. There is full mains pressure at the hot taps if I use with the boiler switched off but only cold water as expected. So I don't think there is any pipe restrictions causing this. I live in a bungalow and have the same symptoms at all hot taps.
I have good water pressure and I think I have good flow rate but have not had these measured. I could pressurise the boiler to over 2 bar without a problem when filling and bleeding the radiators - it's back down to 1 bar now before anyone picks up on that. As far as flow rate is concerned, when I fitted lever operated taps in the kitchen I had to install a restrictor to prevent having an indoor water feature if I turned the tap past 1/4 turn and there is a good constant flow at the bath cold tap. I have no other indication of flow rate other than maybe timing how long to fill a large bucket.
After reading the manual I'm suspecting the diverter valve or diaphragm but I'm new to combi's so not entirely sure. Am I right before I lay into Grant for a fix?
Regards
Jimmy
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