Fixed Rad leak no d/stairs not heating

diverdad

Hi,
Discovered water running out of a light fitting d/stairs. Traced it to a leak on a bedroom rad. This describes my heating system type;
SEALED SYSTEM BOILERS. (Red Expansion vessel in boiler/or on pipework)

1. Turned off rads throughout house i.e. turned off both ends.
2. Shut off everything pipewise in the hotpress.
3. Switched off the heating system at main switch.
4. Used a connection point on the hall rad (installed by plumber 2.5 year ago during extension work) to drain the system.
5. Repaired the leak with some PTFE tape.
6. I reopened all hotpress valves.
7. Restarted boiler.
8. Bleed all the rads.

Result; Heat all around the house except two back-to-back rads in living room and hall. Checked both ends of both rads are open. Bleed rads again.

There is heat on one side of the rads but it won't push through and heat both rads. Other d/stairs rads are working fine, just these two.

Any ideas anybody?

aujopimur

Shut off all the rads that are working, then switch on your heating, this should get the problem rads working.
Don't forget to balance the system.

diverdad

aujopimur wrote: »

Shut off all the rads that are working, then switch on your heating, this should get the problem rads working.
Don't forget to balance the system.

I'm planning on doing the shuting off. I snapped the rad key and need a replacement before I go at them again.

Balancing the system - Is this the fixture at the expansion vessal? Does this need to be done to push the heat through the rads? Whats the usual pressure for a heated system (if the usual cold pressure is 1 - 1.5 bar min)?

aujopimur

By shutting off both valves you have upset the balance of the system.
To rebalance open each lockshield valve (the one with the smooth head) 1/4 turn from closed.
With the heating
on, open each lockshield in small increments until each rad is heating equelly.

diverdad

aujopimur wrote: »

By shutting off both valves you have upset the balance of the system.
To rebalance open each lockshield valve (the one with the smooth head) 1/4 turn from closed.
With the heating
on, open each lockshield in small increments until each rad is heating equelly.

Heat is making its way through the system now. But I was discussing the balancing of the system with lads from work they recomended it but didn't have a plan for doing it.
It sounds simple in theory but sounds like a lot of to-ing and fro-ing. I would imagine that the smallest opening (1/4 turn from closed) would be made on the first rad in line from boiler, next rad would be slightly bigger turn, next rad bigger again, and so on....
Am I right in assuming that?

Thanks for your help with time and knowledge.

aujopimur

You're right, don't let the system get too hot when balancing, run it for short periods while tweaking the valves.

The blue blaa

If i was balancing a heating system,I'd determine the heating flow an return by closing both valves on the radiator before switching on boiler, only leaving the balancing valve coming off the coil in the hot press open halfway so as not to put pump under pressure.. then turn on heating system open both valves on one radiator at a time starting from the closest to the boiler,the flow will be first valve to get hot once both are opened.. leave flow valve opened fully and close off the return valve until it is barely open.. Now as you move thru the house to each radiator gettin further away from the boiler allow the return valve be opened a little more when you get to the last radiator on the line you will have the return opened a lot more compared to the very first radiator you done..

Remember to close the balancing valve in the hot press fully and then just open it 1 turn..This valve is situated in most cases comin off the cylinder in hot press 2/3 the way up and most likely it will be a gate valve,if this valve is left open then it is at this point where the flow turns into the return and travels back to boiler.Your boiler will be gettin the heating water coming back at a higher temperature then your radiators so the stat will think the house is heated an shut off....

p.s. hope i havent confused you

aujopimur

Don't forget to ad inhibitor.