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[vfr-ray1]

Boulter Camray 5 Combi with Horstmann Centaurplus C27 controller plus room stat.

Central Heating side worked okay although system didn't react when room stat was turned up or down.

Biggest problem since installation (DIY installation) was no hot water on demand. Hot water was only available if the CH was on. We have actually run system with water side of programmer switched off but now in warmer weather this means we have to have heating on to get hot water.

Replaced the flow switch which has cured the room stat problem, heating now reacts to temp changes. But still not getting hot water on demand.

CH can be programmed to be off, turned water temp on boiler front to a high setting, boiler would run for a short period, boiler is obviously only raising temp of water held in small tank within the boiler, this will not give enough hot water to wash dishes. For 10-20 seconds really hot water then gradually the water becomes colder.

Could it be the Danfoss Valve that is causing the problem? Any way to test if it is the valve?

[bd3cc]

Have no knowledge of the specific parts mentioned, but if the boiler is a combi, it should not need a programmer, but simply a time clock type device for the heating side of things, as the water should be "on demand" and take precedence over the heating.
Not sure about the the roomstat as have always used TRV's with combi systems, but perhaps that is not the modern thinking.
Hope others, more concurrent with modern systems will reply and enlighten me as well.

[vfr-ray1]

Thanks for the quick reply.

Not up on the jargon but surely all the C27 does is act as a timer as the Camray 5 doesn't have a timer. The C27 is programmed when I want CH and/or HW.

[htg engineer]

Have you got a permanent live to the boiler ?

If you've wired the boiler through the programmer it will only come on when there's demand from the programmer, you obviously need a permanent live to the boiler for the instant hot water, the timer/room stat will control the heating side.

Current regs: you must have a room stat (on any system including combi's) TRV's are still optional, but recommended.

Check boiler wiring diagram, will be found in manufacturers instructions and possibly illustrated on the boiler case somewhere.

When the hot tap is running and the central heating is off, where is there power ? to the PCB ? to the pump ? fan ? could it be the diverter at fault ?

Paying to have the system signed off when first installed or getting an RGI to install the boiler, you would have the manufacturers warranty and the problem could have been sorted straight away.

htg

[bd3cc]

My point is that on a combi, if you want HW on demand, it should not be controlled by a programmer which controls when HW is available. Only the CH side should be controlled by a time clock, and as HTG says you must have a permanent live to the boiler to allow the HW to operate independently.
Thanks to HTG for update on current regs

[htg engineer]

I know what you're saying bd3cc - it's pointless having a programmer with a combi boiler. But they can be and are used (sometimes because people buy the wrong thing or they get one for free off a friend etc etc) - I fitted a spare one to my combi when the timer went off - temporarily, I could have left it there as it does the job. You would just use it as a timer for CH only.

This may be the problem here, if they're wired it up to CH and HW then they'll only get HW when the programmer is calling for it - problems you get with DIY installations.


htg

[htg engineer]

vfr - any feeback ?
is this problem sorted ?

htg