Camray 5 oil combi- intermittant hot water ?

[boulter]

It's a Boulter Camray 5 oil combi boiler.(2001)
When heating is on shower and bath are hot but if I use the shower during the day when heating has not been on it quickly runs cold after a minute.
Boiler and hot water dials are set to 3/4 way round.
Heating works fine.
Could it be the Sika flow switch or the 3 Port valve actuator?
If so which one would you change first and why does the water run cold only when the heating isn't on.
Can I test the above independently to see which is faulty?
If it is the actuator do I change the head, valve or both?

Thanks in advance
Richy

 

[Terrywookfit]

The storage tank in the boiler needs to be pre heated before a draw off.
When the heating comes on it satisfies the Tank stat first.
Make sure there is a supply to satisfy this demand.
Which programmer do you have?
The Boulter ones that fit the control panel, frequently fail to provide an output to H/W or C/H.

 

[boulter]

Thanks for your reply.
The programmer is a Sunvic TLX rfp with wireless programmable room thermostat.
Boiler fires up with flow light when tap opened so can I assume flow switch is ok? and when heating is on, storage tank heats up to set temp on dial so tank stat should be ok?

The tank heating light is not coming on as I am consuming the DHW, where does the signal come from to heat the storage tank as I the programmer only has heating settings.

 

[Terrywookfit]

240v on Terminal 4, JP8 on PCB. comes from Summer /Winter switch via violet wire.
Tank stat then operates a relay R2 to fire the burner.
The tank demand neon should light if there is a demand from tank stat

 

[Boilerman2]

THe last Camray 5 Combi that I hads with these symptoms turned out to be poor wiring connections for the Diverter valve actuator at the PCB

I remade these connections and all was fine..so worth a check?

 

[oilhead]

Remove the diverter valve head to check whether the valve has been leaking into the head, making it 'sticky'. Common cause of intermittent problems on this boiler. Also check that the pump is being switched by the head when DHW is selected.