back boiler system

[versatile75]

am attempting to sort out a problem with our granddaughters heating hot water system its fed from a back boiler to a fortic combi tank unit imi range double coil indirect the system may old the problem is that if the heating thermostat cuts in it drains the heat stored in the hot cylinder I have not attempted to get to the boiler as theres a gas fire fitted the system
programmer will not allow for independent setting for heating and hot water
the granddaughter has just bought this property and there is no info to show how the system works
any info would be appreciated asi cant afford to have it updated yet

 

[DP]

Call a Gas Safe bod out to fix. Ask first if he is familiar with the unit.

If you remove bits, you may not be able to put them together and check for safe operation.

 

[versatile75]

hi sorry for late reply yes am taking you advise as have realised that though
the pump comes on when the heating is selected the boiler is not coming
on even though the thermostat is calling for heat, I isolated the programmer
supply and checked the wiring and found there are no connections for the separate controls for heating / hot water there are cables to, L / N /E from
power in, but only two cables, grey and black to the switched L / N
for the system, all cables run to a junction box with separate choc blocks
as a after thought I may raise a post under electrics or repost to plumbing
but put the question differently, many thanks Roy