Downstairs radiators cold after changing upstairs ones

[mderoy]

I have a Glow-worm Ultimate 30c boiler and recently re-plastered the upstairs and remove 4 of the old radiators that were upstairs 1st floor as they were really aged and looking tired. I purchased new ones matching exact size and all lined up. I purchased new valves and kept nut and olive on the pipes coming in but changed everything above that since I didn’t want to extract the olive to change that lower nut.

After refitting and bleeding air, upstairs radiators are now getting nice and warm but the downstairs ground floor ones none of the pipes flow or return are carrying any hot water at all. If I try to bleed them just cold water comes out.

At first I thought maybe it’s dual zone but it’s always been operated by a single Drayton MIStat N110R thermostat.

Downstairs radiators were not removed. Just drained the system through one of the downstairs ones that’s all.

Any suggestions or advice what I can do and why all downstairs ones are not carrying any hot water to them ?

Thank you

 

[HERTS P&D]

Turn on the heating and turn off the warm radiators, must be a balancing issue.

Andy

 

[Harry Bloomfield]

After refitting and bleeding air, upstairs radiators are now getting nice and warm but the downstairs ground floor ones none of the pipes flow or return are carrying any hot water at all. If I try to bleed them just cold water comes out.

Turn all the upstairs radiators off, via their valves, then run the heating system with just the downstairs radiators turned on.

 

[CountryFan]

As above, you’ve likely upset the balancing of the system.

 

[mderoy]

thanks everyone, I’ll try turn upstairs ones off and then see. Should I turn it off from the flow or the return on each radiator upstairs?

Also, if it turns out to be out of balance. Is there an easy diy way to balance them again?

 

[Harry Bloomfield]

thanks everyone, I’ll try turn upstairs ones off and then see. Should I turn it off from the flow or the return on each radiator upstairs?

Either end will do, the idea is to shut the flow off through all of the upstairs radiators, to force the entire flow to go through the ground floor radiators. You likely have an airlock, restricting the flow to those.

Also, if it turns out to be out of balance. Is there an easy diy way to balance them again?

One bridge at a time - likely your only problem, is an airlock.

 

[Mister Banks]

Did you open the lockshield valves fully? If so turn all the upstairs radiator lockshields to be open a 1/4 turn from closed.

 

[mderoy]

Either end will do, the idea is to shut the flow off through all of the upstairs radiators, to force the entire flow to go through the ground floor radiators. You likely have an airlock, restricting the flow to those.



One bridge at a time - likely your only problem, is an airlock.

Thank you, will try this.

Did you open the lockshield valves fully? If so turn all the upstairs radiator lockshields to be open a 1/4 turn from closed.

yes.

Thanks, I will try this too after I’ve completely shut the upstairs ones off and tried forcing the flow only through downstairs as suggested above.

Thanks all

 

[ChrisJP]

Since you fitted new valves to the new upstairs radiators, and if you didn't deliberately set the lockshields, it's likely that they are as they were supplied - completely open. THAT'S why all the hot water is preferentially going through the upstairs radiators and by passing the downstairs ones. As Mister Banks says, try closing the upstairs lockshields to within a 1/4 turn of completely shut. You may then need to do some experimenting with the amount of opening of the upstairs lockshields to get all the radiators an even temperature

 

[mderoy]

Thank you all for the help and advice. It’s all good now. I shut all the upstairs ones then bled the downstairs ones and they started warming up nicely now.

Another question. all of the new tails that I put on the radiators where I wrapped ptfe tape around the thread before tightening all good except one seems to be weeping. Should I remove and just re-apply ptfe again? Or instead of ptfe is Fernox LS-X a good option for the threads instead of ptfe? Or should I stick to ptfe ? I’ve read that the are thread compounds for threads that are better than ptfe.

 

[terryplumb]

PTFE tape and a smear of LSX if you have any.

 

[mderoy]

PTFE tape and a smear of LSX if you have any.

Ptfe first then lsx smeared on top of ptfe or the other way round?

 

[terryplumb]

I suspect either way will work,although I tape first.