Old back boiler no heating downstairs

[norfolkinesox]

Over the last few weeks I've struggled with getting the downstairs radiators hot,the pump is turning (it's a grundfos 15-50 pump) I've checked the three way valve ,that is operating as it should,can the pump still be faulty?the only time I get any heat in the downstairs radiator is if I select heating only but still not hot only Luke warm,thanks for any replies

 

[norfolkinesox]

After reading some sticky topics I removed centre screw from pump ran pump and tried to stop rotation with pressure,it couldn't be stopped so I take pump is good,I've switched off rads upstairs one downstairs is getting war miss but next in line still like warm........I have one rad in kitchen but this is permanet lay isolated as fridge backs onto it could leaving one like this cause issues,tthanks

 

[Netdragon]

Try turning upstairs rads off and run heating, if they get hot see if any cold spots. Also chech small tank in loft for water and the colour and if its hot.

If tanks hot its pumping over, cold spots in middle of rad both normaly mean system is smudged up if the pump is ok.

Could also be the system needs balancing/turn up pump speed too for a while.

 

[norfolkinesox]

Thanks for reply ill check that lot out,I have turned up stairs off and downstairs ones hot but other only warm,I'll go check what you suggest

 

[norfolkinesox]

Speed has been on three for quite a while

 

[norfolkinesox]

Checked tank in loft it's very Luke warm not cold so to speak,pump speed is onhigh (3)as it has been for a while,I have one radiator permantly isolated due to fridge backs on to it will this not help ?others downstairs with upstairs off are warm but not hot don't seem to be cold spots...........I'm confused lol
I've left upstairs isolated and leave heating on see if this clears system

 

[dcawkwell]

You pump has gone.
The shaft can still be turning . Doesn't mean the imeller at the other end is.
Had one like it only as couple of weeks ago. Impeller was just free to spin.

Other possibility is a blockage.

 

[norfolkinesox]

Thanks for the reply,today I've turned off upstairs radiators downstairs got hot,then opened stairs downstairs went cool I balanced radiators up stairs and downstairs is still cool,so maybe pump is knackered as you said,just when I took off carp I couldn't stop it spinning but like you said impeller could be issue,just hope my isolation valves are ok either side.
Is that freeze stuff any good for the pipes to change the pump if isolation valves are no good?

 

[Netdragon]

Sounds like you need to stick a new pump in, with the tank being warm I suspect some sludge in system so a tub of system cleaner and a flush.

Something you don't want to diy in cold times, but if the pump valves are like a gate valve with a shaft you may be in luck,if not a new set pump and some chemicals may get it going.
And a full drain down, tank in loft down to below pump position.

 

[Netdragon]

Thanks for the reply,today I've turned off upstairs radiators downstairs got hot,then opened stairs downstairs went cool I balanced radiators up stairs and downstairs is still cool,so maybe pump is knackered as you said,just when I took off carp I couldn't stop it spinning but like you said impeller could be issue,just hope my isolation valves are ok either side.
Is that freeze stuff any good for the pipes to change the pump if isolation valves are no good?

Only if you work fast and no problems if there is your buggered.

You can get a bung kit that makes a tanked system tempory sealed once you stick them in the tank pipes, and drain off the water presure, you are mostly dry part from some dribbling and gurgles now and then. Not fool proof tho.

 

[norfolkinesox]

Thanks for all your help appreciate you taking the time out and reply,I'll go for pump change........wish me luck!lol