Heat Pumps are Simpler than You Think : My Vaillant Arotherm Plus Schematic 

Great video - super useful and very clearly explained!

Had a quick look at these already but thanks for talking through it. I really want to fit this myself, be good fun :-) Just need loads more time and money :-/

Well done. The actual positioning of the mag filter is usually a question of convenience/future ease of access as long as it is on the return. Theoretically, better on the return just prior to the buffer (to prevent the buffer getting full of crap) but I would not lose any sleep over where it is now.

Nice explanation. We are in the Netherlands with a gas system still and something I keep finding is that the UK does not seem to often talk about smart thermostats with OpenTherm. Here the requirement for newer systems is that the room thermostat talks to the boiler and sets the demand not just as on and off but as an output level. This means that if the room with the thermostat is especially cold then it can demand the boiler fire at full power and if the room is almost at temperature it can demand a lower output. I'd imagine that we also have outside temperature compensation and to be honest I'd have thought that a simple system would just rely on internet connectivity to get the approximate local temperature so that in the depths of winter the flow rate can be adjusted.

Hi great explanation (especially for us less inclined to be totally interested in full system explanations). My biggest concern, as we are looking to get some quotes for a heat pump system, is the amount of space that all the components will take. We have a combi boiler that’s it, so you can imagine having a immersion tank, plus any other required components (expansion tanks etc) will mean we have to find somewhere for those units to go. I am wondering if that in the future that a larger but more compact combi electrical system may become available, I’m even considering splitting the heating and hot water systems which yes means more system components, but I think that more electrical alternatives will become available as we move to a ‘non’ gas environment. Sorry this might have been a bit of a mind dump!

This was a great video. Did you replace any of the microbore or just the radiators?

Really could do with the link to the files you was showing installing my first one and used to wiring other units, plz let me know where i can find these ?

Regarding the MagFilter position - I believe they are generally shown in the Rad htg. circuit and not the 'whole system return' as modern plumbing in the HW system will be in Copper, Brass or Stainless Steel which generally doesn't rust as opposed to the space htg. system which largely has steel rads and is a good source of rust / magnetite! Having where you do won't hurt anything but will only pick up the debris after its passed ALL around the WHOLE system. A good system chemical treatment will minimise rusting but it still does occur.

Nive overview. I assume you have some microbore piping on your rads. If not, I’d be surprised that you need a buffer tank for your system.

Talking about secondary circulation is complicating things a bit, especially for those who are not plumbers. A secondary circuit is just two domestic hot water pipe leading away from the cylinder to create a loop out to the furthest point in the house with a bronze pump that circulates the domestic hot water so one doesn’t have to wait to get hot water. Most houses don’t have this, it’s mainly use in hotels and very large house like Buckingham palaces!

Can I get a copy of that Vailiant Schematic please

Hydraulic separation for the laymen.

They are quite simple. Went on a free government course to understand and they made it complicated.

The hot water in a cylinder should be above 50°c preferably 60°c as at 60°c legionella cannot survive, this should happen at least one a week.