DIY Doctor

System Boiler problem

Postby 1norab » Tue Jun 17, 2008 10:46 am

Hi, I have an Ideal S28 system boiler. The problem is the DHW is not working.
The CH works fine. Both the Motorised valves for CH and DHW seem to be working ok. If I call for CH only, the boiler fires up ok.
If I call for DHW only, the pump, motorised valve and fan kick in but just as you think the boiler is going to fire up, it doesn't and goes into fault mode. The same happens if I press for DHW to join the already fired up CH, it shuts it all down.
I have checked the fault diagnosis with the manual and the lamps (x3) tell me its a Faulty Primary Circuit (no water or absence of flow).
I have removed the Flow switch from the diaphram and if I keep the switch pressed in and call for all 3 combinations the boiler fires up ok on each one (CH only/DHW only/CH + DHW).
I have also noticed that the pin extends out 11mm when the CH is called. But only extends out 8mm when DHW is called. If I have the CH on and press for the DHW to join in, after the motorised valve clicks into play the pin retracts back to 8mm and disengages the Flow Switch and the boiler shuts down. The pin then retracts back into the diaphram.
The pin, when protruding out, does not have any resistance if i manually try to push it back in at any of the 3 combinations (CH only/DHW only/CH + DHW).
It appears that the pin doesn't reach the flow switch to engage it when I call for DHW.
Has anyone got any idea as to what could be causing this? Any suggestions are most welcome. Getting a headache trying to solve this. :cry:
Rank: Labourer
Progress to next rank:
Posts: 2
Joined: Tue Jun 17, 2008 9:56 am


Simply Build It

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics