Worcester Bosch Greenstar 24i return pipe cold, downstairs rads cold

[magga]

Hi everyone,

Had a bit of a nightmare with a Worcester Bosch Greenstar 24i system boiler, problem as follows:

Upstairs rads getting hot, downstairs rads still cold, return pipe into boiler also cold.

We've had a power flush, new fan in boiler, new pump, still the same problem. The first rad on the system upstairs gets boiling hot, flow pipe on first drop warm, not quite reaching rad, return cold. All other drops cold on both flow and return.

The downstairs rads aren't blocked, because opening the drain valve on the return of each drop, and the hot water does get into the rad.

The return pipe into the boiler is also cold, there's some kind of valve on this return pipe just above the boiler, is it worth getting rid of this, as I believe it's not needed and have been told it could be restricting the flow.

After the power flush, the downstairs rads worked for around a week, but now they're not getting hot again. I do a bit of plumbing work myself, and have put new TRVs and lockshields on the rads, but we've also had 4 plumbers out, and the problem still isn't resolved.

The only thing I can think it is, is a blockage on the return pipe somewhere, but is this even possible being that a full power flush has been done?

Any replies really appreciated!

Cheers

 

[jonnyswamp]

What size are the pipes feeding the radiators, 10mm or 15

 

[joni os]

Is the, "some sort of valve " on the return a Y strainer and if so check mesh not blocked.

 

[snowhead]

What setting is the Pump on?

 

[magga]

Thanks for the replies, to answer:

All pipe is 15mm to rads, 22mm flow and return from boiler.

The valve does appear to be y type valve yes.

The pump is on setting 3.

Shall I check the y valve, or just remove it and replace with a magnaclean?

Thanks guys.