Slow radiator....

[Enzo]

Looking for some suggestions....

Have a gas fired central heating system, which is working perfectly except for one thing.. The living room rad takes forever to get to the correct temeprature, sometimes 40-45 minutes after the others. There are 10 rads in the system, and this one is the 6th. The layout of the system is 5 rads upstairs, 5 downstairs, and the troublesome one is the first downstairs rad. It does eventually get to the full temperature, just seems to take forever, so for example timing the system to come on for an hour during the day is wasted on this rad.

Any suggestions?

Thanks,

Enzo

 

[jonesey]

Try balancing your radiators by turning down one valve on each radiator which gets hot. Some radiators will only need the radiator valve only half a turn open. This will push the heat through your system more efficiently.

 

[Enzo]

I forgot to mention, all rads have TRVs fitted. Could this be a factor?

 

[taydo]

take the head of the trv and jiggle the pin around it might be sticking

worth a try

 

[breezer]

i always thought (from this forum) that all rads should not have trv's, one should have no trv or by pass valve.

would one of you guys confirm / deny this?


what if the radiator is semi-sludged?

what about turning all the other rads off ?

 

[oilman]

Your thought is corrct breezer. One of the valves should stay open, or there should be a bypass. The bypass is often a gate valve which is in efficient as water goes straight from flow to return, and effectively reduces the pump pressure for no benefit (like heating somewhere).

If this system has a gate valve bypass, it could be open too much.
Another possibility is the room with the slow rad is already warm.
Is this the case?

 

[geeza]

Fully open both valves on the rad thats giveing you trouble (if trv take head off & make sure pin moves up & down freely).
Close all other rads down on the lockshield side only - run boiler.
Provided the rads bleed and both valves are fully open rad should warm up immediatly, If not you have probs.
Work back and balance rest of rads to 11 degree diff between flow & return on the rest of the rads by opening lockshield till you roughly get desired diff.

You can have trv's on all rads depending on what bypass you have.
most new combi's a bypass built in.

A gate valve bypass could give problems if open to much worth checking if you can find it !

 

[Enzo]

Geeza,

firstly, system is new (less than 10 months old), and is a sealed system - Potterton system. As it was new and I was still working on renovations, I hadn't fitted the trvs (too much dust/building grime etc) - they were running with the simple cap cover only. This rad had the problem then, but was resolved once and for all by closing down all the other rads - there was a high spot which was removed by doing this. After that, no problems any more.

Problem only resurfaced recently when all decoration/building was finished, a similar sized rad in the next room was reconnected to the system, and trvs fitted. That's when this rad started a go-slow. As I said, it does eventually get piping hot, but takes almost an hour. I had the system balanced before, but do you think I need to re-balance? Also, as this is the only rad giving trouble, should this be the one rad where the lockshield side is left fully open? It's open a good bit already, and when it does get hot, it gets really hot, so not sure if it needs lockshield open even more?

As regards a bypass - not sure if the Potterton System boiler has it?

Thanks again,


Enzo

 

[taydo]

If my memory serves me correct on a standard y plan system the three port valve acts as a byepass, when it is not called for heating it defaults back to the cylinder side.