No heat in radiators downstair

[mcniven]

Alright guys, i've got a tricky one ongoing at the moment.

Recently changed a glow work system boiler to a vokera unica combi, linked f&r in the usuall way in upstairs cylinder cupboard etc.

Now when filling the system, bled all the rads, everything pressurised just fine, turn the heating on, and only upstairs is heating? Ive tried closing all trvs etc to push the heat through, but nothing happening. Even when I open downstairs drain valve for about 5 seconds heat comes through but its as if its just no circulating down stair?

I removed a downstairs rad and opened the radiator valve and eventually heat comes through, I thot maybe sludge is stopping circulation of heat? So I tryed to flush system with inhibitor nothing...

One thing is, when the f&r leave the boiler they go upstairs first, then drop for downstairs. Ive never came across anything like this bare in mind, all tails to rads are 8 bloody mm!

Any ideas? Cheers team

 

[dontknowitall]

I'd look at the pump. Probably needs bleeding but if it's been going for too long without water passing through it might be shot.

 

[mcniven]

i bled the pump, to be fair, upstairs is also taking about 20 minutes to heat!? thats cant be right either..

and changing speeds of the pump i can her the speed change, is that normal? i have not done much fault finding mostly an install background! cheers mate

 

[dontknowitall]

Is the pump knackered? (I hope I'm not teaching you to suck eggs but if you remove the bleed key and put a 3mm flat headed screwdriver into the pump (when it's off!) does it turn easily?)

 

[SimonJohns]

Have you isolated all upstairs rads at lockshields

Have you made each rad downstairs work by only having one on at a time

My bet is on slight air locks with microbore and a hint of sludge

 

[jase158]

I was going to say air lock, did you drain down from rad or from boiler, did you drain down each drop or just the one?

 

[REDSAW]

sludge settled at bottom of system,

turn off all tops exept one that heats the most.

turn of all bottoms exept one to work on (first downstairs) then hammer pipes, trv and rad untill heats up, then the next.

also check the feed to the pump has water in it and tank valves are open and flowwing etc.

 

[mcniven]

We went again today and plumbed it in straight to downstairs also and radiators got some heat opened the rest up the stair and nothing the pump is absolute roasting!

So I removed bleed valve, and could stop the pump fairly easy with it on setting 3, I called Vokera and they said it's the pump? And send out service engineer for warranty call

You think this is right? The flow and return are mega warm at the boiler.. Just maybe not circulating properly?

 

[GasmanxxxR1]

Flow and return defo the right way round?

 

[mcniven]

Iv linked them just after the boiler so wouldn't make a diff anyway would it?

 

[mcniven]

Even closest rad (bypass) heat at bottom of rad no circulation

 

[GasmanxxxR1]

is there a zone valve somewhere

What do you mean you have linked flow and return below the boiler?

 

[dontknowitall]

You say the pump is roasting but are the pipes the same temperature on both sides, and what about further along the pipe run?

 

[mcniven]

Roughly same temp on both the pipe run is fine some
Of it is under floor in the cylinder cupboard which was removed when switching to combo the flow and return are hot but when it's going to rads it's like it's not circulating?

 

[REDSAW]

have you bled the pump?.

 

[mcniven]

Yes redsaw,

That was done today and when I put the screwdriver in the pump it stopped with ease. The boiler is brand new, so I called Vokera about it for a new pump.
There gona sort that tomorrow.