Ideal Mini intermitent direct hot water

[jrparadise]

Hi, Ive got a 5yr old Ideal Mini C28 combi. The central heating side of things works fine, but recently the direct hot water has been playing up. If the central heating is on, then the DHW works fine. If the central heating is not on, and I turn on a hot water tap, then sometimes I get hot water, and sometimes I dont. Ive replaced the hot water flow switch, thermistor and more expensively...the full sequence ignition board...but the problem still persists. Does anyone have any ideas what I should look at next? im wondering whether the DHW filter and flow limiter might be jamming? would this cause such a problem? Many thanks, James.

 

[fireblade]

Could be the diverter motor remove it try the tap and see if the pin shoves out other than that it could be a faulty gas valve not going onto full rate

 

[jrparadise]

Many thanks fireblade - Ill investigate as suggested.

 

[Adrian.]

Had a similar job other week, investigated hall effect sensor which lit up so proved worked, took off microswitch and proved manually it worked, took apart diverter pin assembly and greaed, was all ok, cleaned by-pass pipe behind plate, in the end it was primary diaphram at fault, was stretched not split and even though primary ie for heating and hot water replacing in it did the job. Must have been to do with needing more pressure for hot water or heating or vica versa.