Glow Worm Ultracom 30 cxi - no heating

[gazzdaspazz]

Help - we recently tried the CH for the first time since before summer and although we get DHW the boiler doesn't fire up for CH.
Room stat clicks at about 23 degrees - have even tried replacing the stat but made no difference.
The internal timer on the boiler is disabled for CH although I have also tried it with timer on and set to come on but still no CH.
Pressure is fine. System has been completely drained and refilled about 4 times. Rads have been bled etc.
Have checked the Diagnostic Menu - the code d8 - "external controls heat demand" (which I assume means room stat in my case) d8 shows a status of 0 when I believe it should be 1.
Boiler is less than 18 months old.

Any advice would be appreciated.

 

[mickyg]

Have you got the boiler in the correct mode? there should be a radiator symbol in the display, use the mode button to alter. You can try linking out the stat in the plug in the bottom of the boiler, by linking L and R.
Additionally your boiler is still under guarantee, but I suspect a control problem.

 

[gazzdaspazz]

Thanks for replying.
Yes I have the radiator symbol on the display. I'll have a look at what you suggest after work tonight.

Thanks

 

[gazzdaspazz]

Actually I need to elaborate - if I switch the boiler off and on, it seems to heat the water in the boiler to the right temperature - so I know it can fire up. Also the first 30cm of pipe coming from the boiler starts off hot then warm, then after that cold which seems to me like heat from inside being transferred a little way down a the pipe. It certainly makes some noise when it is "on" so something inside seems to be working. If it was getting pumped around the heat would transfer around the pipe but it isn't.

Could this be a blockage/sludge in the system?
If so I'm not sure why the boiler thinks there is no external demand for heat (assuming I've understood the d8 status code correctly).

 

[londonpop]

Hi Gazz, had the same problem installing Ultacom CXI38. CH Isolation valves are closed from factory and a bit hidden. Make sure they are opened up with an allen wrench before you try again. Symptoms are exactly the same we had before discovered they were closed. Instructions leave this step out completely as we found.

 

[morrismini]

Is the pump seized after the summer? Was DHW being used in summer?

 

[gazzdaspazz]

Apologies for delay in responding, haven't been on here for a bit.
The chap who installed it found a bit of sludge in the system and now we have gone from one extreme to the other.
With all valves on the rads closed and the room stat turned down the rads stay cold - OK so far. If I open a valve the rad stays cold - still OK. If I turn the room stat up the rads with open valves get hot but some of those with closed valves get very slightly warm - not too concerned with this. Biggest problem now is that if I turn the room stat down again the rads stay hot until I close the valves. So although the stat is not calling for heat the boiler keep churning away.
Other things I've noticed are that after the boiler gets to a certain temp, albeit below the set point, there is only one flame on the display when we used to get 4-5, and it creeps very slowly upwards in temp. I also think it is ignoring the CH and DHW setpoints and trying to reach the maximum temp.
Might post this as a new topic but if you happen to read this and know the answer I'd be very grateful.

 

[suntacasa]

I had the same problem and yesterday I had someone coming to my place and after few attempts he managed to disable the wireless room controller (the wireless unit on my wall) and now the boiler works on its own CH controller (internal). It seemed that in my case it was something wrong with the room controller. In fact the room controller was communicating well with the unit fitted next to the boiler but it seemed to be a malfunction between the receiver and the boiler itself.
Obviously this is a temp fix (CH working on its internal controller) but I'll keep you posted with what it happened...

 

[suntacasa]

My boiler is a Ultracom CXI 38