Would never consider running a 3 wire set up rather than 5 wire as the flow and return sensors will be too temprmenal depending on the system, viessmann said you can't and Vaillant/glowworm energy say you can but you will get fault 83 from time to time. Not sure on baxi but never a good idea hence why apart from baxi offer it
Ok I will have a look at the viessmann heat only cheers lads.
When googling pump over runs, with a thermal store and heat only boiler how is the pump over run controlled/timed?
I have to quote one of these, (new Boiler onto existing thermal store)and if i go with a Boiler that requires a pump over run how is this controlled so it's not just be cycling?
I just looked at veissmann heat only installation manual and it doesn't say anything about wiring with no pump over run. It don't say much about wiring at all.
Just wire the pump back it will run for a period of time, set by electronics on pcb, but don't do it on a Vaillant/glowworm as you will get f83 I promise you that
My mistake just checked it does need one appologies kop. Seem to remember viessman do a add on to their heat only to get over the pump over run problem will try and find it, this maybe of interest to you regards kop