external boiler frost stat

[simoneve]

hope someone can answer this,i have a new grant vortex external oil boiler now the question is this, when the frost stat kicks in at the pre set 5 degrees should it actually fire up the boiler (and therefore the central heating)or just activate something within the boiler that only warms the boiler itself.Because my boiler seems to be starting up well above 5 degrees (when the timer is off) and starts the central heating up!!
Hope this makes sense and that somebody can give me an explanation.
thanks

 

[simond]

The Grant Vortex external has an internal frost stat that starts the boiler and pump.

In a normal system with 2x2 port zone valves an auto bypass will allow water circulation without opening either valve and warming the rads.

In a 3 port valve situation (like a T junction), the 3 port valve always has one port open, so the boiler kicking off under the frost stat will either warm the CH or HW or both.

Not ideal, there are ways round this - your installer no doubt can elaborate.

 

[simoneve]

thanks for the reply,yes i do have a 3 port valve,i haven't spoken to the plumber yet but in the meantime can anyone make any suggestions to solve this problem.By the way this morning i turned the power on at the main switch but with the programmer turned to off and the boiler fired up straight away(it was certainly above the 5 degree frost stat setting!!!)

 

[simond]

Things you can do are;

Check the 'test' switch on the boiler facia is set to off

Check the wiring from the system controls to the boiler wiring panel with a multimeter - it might be that your issue is not related to the frost stat. For example, the <switched live> and <permanent live> on his wiring connection could be reversed.



When opening up the boiler panel bear in mind that the stuff in there is live and standing outside constitutes a high risk of a shock being lethal.

NB: If your installer has done a proper job the supply will be properly earthed and protected by a 30mA RCD.