Is my pipe/rad layout poorly designed?

[foxhole]

What speed is pump running at?

 

[JohnD]

I'll be looking into that bypass asap, as that could easily be the answer.

Mine does not need, or have, a bypass.

I queried this with the manufacturers. When it stops firing, it continues pumping round for ten minutes, leaving the motorised valve open to whatever it was doing when demand stopped.

If you can touch the circulation pipes, you may find they are hot going towsrds, and coming away from it, even if all the radiator valves are closed.

 

[b175c15t110]

Mine does not need, or have, a bypass.

I queried this with the manufacturers. When it stops firing, it continues pumping round for ten minutes, leaving the motorised valve open to whatever it was doing when demand stopped.

Well that's beyond my knowledge for sure. I can only find out if there is a bypass, and the heating engineer can take it from there.

He's been fitting baxis for many years, so may know if there's a motorised valve etc. I will ask him when he gets back on Monday.

 

[b175c15t110]

So there "was" a bypass.

I've had the floorboards up and can clearly see the pipes for a bypass, but a previous plumber/gas engineer has squashed the feed pipe flat just after it tees into the radiator to prevent flow to the bypass.

A brief test this morning shows that it hasn't stopped the water completely, as the other side of the flattened section became piping hot very quickly, but it has clearly reduced the flow significantly.

I will get this chopped off and capped properly, but I doubt it has anything to do with my current problem with the upstairs rads.

As JohnD suggests, I will try more balancing by turning down the downstairs rads even further. Looking at a 1/16 turn on them, so maybe that will help? Beyond that, it's a power flush on Monday, and beyond that, is it the boiler that doesn't have enough poke?

I looked at the pump last night, but the view was not sufficient to see a pump speed adjuster. There was a knob on the top, but as I couldn't see what it did, I left well alone!

 

[b175c15t110]

The power flush on Monday morning did it.

It wasn't the rads, as after being on for 5 hours with downstairs rads turned off, the upstairs rads would eventually get hot top to bottom.

So there was clearly a partial blockage somewhere in the upstairs pipework, or possibly in the short section downstairs where the upstairs feed came from.

It's now heating upstairs to piping hot in 5 to 10 minutes, and I'm gradually opening up the downstairs rads to balance the system. Seems to be pretty perfect at the moment.

So thanks to all those that commented here