Apollo 30/50

[EdwinWatts]

Hi
I am currently having problems with my Apollo that I have maintained for 20+ yeras now. The timer fuse keeps blowing and when I replace and leave with no demand on either water or heating then set to either high or low on the boiler it comes on!
Any ideas please

Ed

 

[namsag]

Have look at the motorised valves possible leak in or around them causing fuse to blow.
And microswitch inside motorised valve is faulty causing boiler to come on when no demand

 

[picasso]

disconnect the pump and see if the fuse blows as quickly, dont run the boiler for more than a few seconds, the test is just to see if the pump is blowing the fuse .

 

[EdwinWatts]

Hi Namsag and Picasso

Thanks for your info on the pump. Before I rip up the floorboards in the attic could you advise firther. The pump comes on immediately when I switch the timer back on even with no demand. I have tseted across the timer and it is showing a short circuit across the cylinder stat switch. Is this an indication that it is the timer that is faulty - I tested it out of situ. Thanks Ed

 

[picasso]

If the pump is running with no demand and the system is cold then the pump overrun stat is stuck, not quite sure what you mean by short circuit across the cylinder stat ?, is the fuse still blowing when you switch the hi/lo stat ?

 

[EdwinWatts]

Hi picasso and thanks for your help.

Do not have spare pum overun stat to test - will pick one up Tuesday. No the fuse does not blow when I switch to Hi/Lo but does when I run through any of the water/heating demands on the timer. The short circuit is across the the 2 pins 3 and 4 on my Switchmaster 9000 timer that relay to the cylinder stat - I cannot see that this would be a correct configuration so assume that the timer is knackered and could this be making the constant demand on the pump? The pump comes on immediately I switch the timer on at the mains.

Thanks - Ed

 

[picasso]

pins 3 and 4 on the switchmaster are HW on and HW off, do you have a 3 port valve ?

 

[EdwinWatts]

Hi picasso

yes it is a 3 port valve so what does this mean?

 

[picasso]

pins 3 and 4 on the switchmaster will be connected when the cylinder stat is satisfied, try turning the cylinder stat down as far as it will go and see what happens.

 

[EdwinWatts]

Pins 3 and 4 are short cicuit when I have got the timer unit out and disconnected from the system and back plate. I assume that it is knackered unless you think otherwise. I understand that the CentaurPlus C21 is a compatible replacement - but are the pin configurations the same - they seem to be slightly different? Really appreciate your help on this picasso - I am a little lost here.

 

[picasso]

3 and 4 shouldent be connected so I reckon your right about the programmer, the centaurplus isint a direct replacement for the 9000, it uses a different backplate and needs to be rewired, its not a difficult job and usually takes about 20 minutes, I cant find a direct replacement so it looks like your going to have to change the back plate anyway.

 

[EdwinWatts]

Thanks again and will keep you posted on developments tomorrow.

 

[EdwinWatts]

Have installed the new Centaur Plus times and the system operated on hot water very well. However, when I switched the central heating on the timer fuse blew immeiately again. So the demand on CH is the problem. Any ideas?

 

[picasso]

3 port valve would be my best guess.

(as namsag said in the first reply)

 

[EdwinWatts]

Hi Picasso and Namsug

My many thanks to you both for your help on this problem - especially to picasso. It turned uut to be the moterised 3 port valve as namsug said on first post so well done. Thanks again - I think this forum is brilliant for non spaecialists and appreciate how people with experience are willing to contribute.
Regards

Edwin