The advice on this forum at the time was that I should install some check-v alves to prevent the chance of thermosyphoning via the boiler and/or the he ating, and my question regards this.
The boiler circuit will consist of; pipe from lower part of cylinder into ' cold' side of blending valve (to allow control of boiler return temp and ho pefully force condensing whilst maximising output temperature to heat the t hermal store from the top down). Output of blending valve into pump. Outp ut of pump into boiler. Output of boiler into upper part of thermal store and also via T into 'hot' side of blending valve. My question is; where do I put the check-valve? My thought is between outpu t of boiler and cylinder, but are there any rules, such as always before a pump, or always after a pump etc, or does it really not matter?
Same question regarding the heating circuit; The heating will flow from th e upper part of the cylinder into a pump, and then on to the rads, but shou ld the check valve be before or after the pump?
Finally, I've already got check valves something like this; http://www.scre wfix.com/p/22mm-single-check-valve/61237 are these going to be suitable for use in heating circuits as I just notice d that it says they contain plastic parts? (It would have to be pretty pat hetic plastic to melt at less than 100 C !!) Also, are check-valves genera lly reliable?... would I be as well adding isolating valves either side to facilitate replacement, or am I being over cautious??