Yours is more sophisticated than mine as I only have access to HW or HW and CH together. Can't have CH on its own.
The tank thermostat is on the side of the tank and is adjustable, so I can set it to any temp and it clicks when it gets moved past the temp the tank it at, so I know it is working. I have it set on 60 degs C all the time. (The whole system is programmed to go off during the night and back on in the morning. but it is on constant while I am working on it, unless of course it is "off".)
There is one electronically operated valve which also has a small lever underneath it for some sort of manual over-ride. Don't really know how to use it so I leave it alone.
The pump over-run stat tends to fail every now and then and leads to banging pipes if not attended to. When I first moved in with W the pipes used to bang like crazy, she told me that they, i.e. she and her ex had had plumbers in to try and fix this but they never managed it. I had a look at the installation manual etc and thought that this could possibly be it. So I went to buy one, the guy in the heating engineers spares place told me "these don't often go" but once fitted the problem went away.
(The boiler has only 3 positions, High, low and off) and I am now following the procedure I eventually found online.
A quick look online only tells you basically to just bleed the rad in question. Well I have done that to all of them and they all allow water to come out, NO hissing at all.
There is also a bleed valve connected to a pipe Tee-ed of the pipe to the tank coil, in such a way that it is above the height of the top of the tank. This one you can turn with your fingers. This was the ONLY part of the heating system that I touched when trying to turn the hot water off i.e. isolate it so I could work on the hot water feed in the utility room.
I have to believe that when I did that (the whole system was off,) the rads and pipes etc were cooling and managed to suck air in through that bleed valve. When I did it, there was no noise and no water came out. Since then I have bled it and that time water did come out.
So all rads are off except the one in the garage. As each one gets properly off, I will turn the open the valves on the next one and once that one starts to heat up I'll close the valves on the previous one.
So then on like that until they are all done. Banging on pipes I can get to, rads and valves with a big rubber hammer as I go.
Once I have done them all than I'll turn all rads on, one at a time, seeing if any still stay cold.
I hope I'll be lucky.
Irn Bru.
