When demand for h/w , boiler kicks in and off again after about 30 secs , then back on then off and so on . C/H loop works ok but overpressurises and opens up relief v/v , so i run it at a lower pressure to compensate. H/W temperature is adequate when c/h is on as heat in boiler warms cold water up (when boiler not fired up with tap open ,I think) But now that Spring is here c/h not on as much and cannot get a decent bath out of it now !!!!!