HRM Wallstar Oil Boiler - Advice please

[John.g]

I think I saw somewhere that the Firebird store temp has a hysteresis of 5C so the burner may not cut in instantly on flow demand? Also one would think that the very nature of a store would allow a draw off of maybe 5 litres or so depending on where the probe is positioned. It would be interesting to get some feed from someone with a stored combi oil boiler.

 

[SJB060685]

All stats have a hysteresis but I couldn't tell you how wide it is on the thermistors or stats used. If you look at the flowchart for combi boilers you'll see a series of relays and stats and other components on PCB's. Of all my manuals stored show flow switches bringing on the boiler and pump when a hot outlet is opened. The store stat can also bring on the boiler to heat when no outlet is open to top up.
Another thing I will say is the newer firebird combis don't use a flow switch but instead another thermistor on the cold inletto PHX, which detects a change in temperature and brings the boiler on that way.