Plumbing (central heating) quiz...

[kp7722]

In my previous post I described how I've messed with my current CH & HW system to make it fully pumped (S plan). I think I've messed up a perfectly good system but it is totally undo-able. What I need to know is from the following information would the old system have worked successfully so I had HW only when I needed it, CH only when I needed it, and or both. And would it have been fully pumped?

the diagram: http://www.facebook.com/album.php?aid=9071&l=278af&id=544791297

this is definately how the old system was piped up. when HW only was called the HW valve opened, the pump started running, and the boiler fired - although the valve was knackered so this actually couldn't be tested (the valve was set to manual open). when CH was called the CH valve opened, the pump started running, and the boiler fired. when both CH and HW was needed both valves opened, the pump started running and the boiler fired. on all cases the system stopped when the approriate thermostat(s) were satifsfied (and there is NO pump overrun).

can you tell me how this system worked unless the valves were on the return. i have no idea. can you also label pipes 1-3 with where they are going/coming from. they run under the floorboards so i have no idea.

my theory is the valves are on the return. pipe 1 comes from the rads (pipe 1 definately heats up with the CH but the rads seem to be hotter than this pipe, suggesting a return?). pipe 2 goes back to the boiler (pumped for both HW and CH) and pipe 3 is the flow to the HW tank, to the coil and then to the HW valve (also the expansion tank). underneath the floorboard i think is a T piece which splits the water from the boiler between the HW tank and rads and can only flow if the valves on the return are open. is this feasible? any other ideas?

Cheers,
Paul.

 

[Paul Barker]

Yes the old system is also s plan, yes pump is on return which would go right back to boiler with no t's off it, combined feed and vent is on flow.

Why did you change it?

 

[kp7722]

I thought the flow was different to what it actually was. I convinced myself that it was wrong and set about changing it. I was basically a muppet. At least I know how to correct it. Shouldn't take me long...

Can anyone see anything wrong with how the old system would have ran? Are there any issues for having the valves on the return? Surely it just blocks the flow further down the pipe - it's not any less efficient is it?

I've already set myself the challenge of understanding a system completely before messing with it. At least I know my plumbing skills are upto scratch! one rad moved, nearly all rad valves replaced for TRVs and new lockshields and totally screwed up the main piping! at least it was all watertight!