My Ideal Mini C32 has DHW problems

[dinkytoy]

The Ideal Mini C32 combi boiler was installed in the house when I bought it and probably a few years old, had it serviced and checked and it's been OK for a year. Recently the water was not heating up (gas not firing) unless the CH was switched on, frost setting would do. Then it got worse, HW cool and troublesome and my plumber cleaned the diverter valve and OK again for a few weeks. Failed again and he's now fitted a new valve. Still not right and it seems to be an intermittent fault. HW OK for a few minutes and then runs cooler with less flow, gas still burning. Seems better if CH switched on, again frost setting appears to work. Green LED seems to be flashing properly.

Don't really want to splash out on a new boiler having spent £200 or more. Any ideas?

 

[plummerman]

The ch flow thermistor which controls the frost protection is goosed. That's why it's firing, flashing frost protection at times. Thermistor drops in and outta calibration

Or your plate heat ex is blocked but your plumber should be able to tell if that's ok by checking temp diff/rise across the plate.