Filling loops

[victoria_sponge]

I have an Ariston boiler whose pressure dropped to zero last night after we bled a radiator without thinking things through. The boiler doesn't have a filling loop, but I can see the two points that the filling loop ought to connect. If I nip to my local DIY/plumbing supplies shop, is this the kind of thing they'll stock and if so, are there a variety of sizes or does one fit all boilers? Also, what procedure should I follow when restoring the pressure - should the boiler be turned off: which valve do I open/close first (at which end of the filling loop, I mean) - and for future reference, what is the best procedure to follow when bleeding a radiator to make sure the pressure doesn't collapse again?

Very grateful for any advice.

 

[sterose]

If you bleed radiators, you will eventually see a pressure drop - there is no way around this (unless the boiler fills itself).

If there are valves that the hose ought to connect to, then it should be as simple as connecting the filling hose, and opening the valves - and shutting them when you have filled the boiler, and then removing the hose again.

By the way, all 3/4 inch threads should connect to the valves, so any hose should do for the purpose.

 

[MANDATE]

When you open the valve to increase the pressure do it very slowly while watching the pressure rise, if you open it too quick there is a chance of increasing the pressure to the point that the pressure relief valve (PRV)opens.
When the PRV closes again, there is a chance of it not seating properly and giving you another problem you could well do without.

 

[ChrisR]

sterose - I've never seen a filling loop which wasn't 1/2" connections...

 

[sterose]

"sterose - I've never seen a filling loop which wasn't 1/2" connections..."

Youre the boss, but im fairly sure ive seen the actual threads (not the pipe) on the end are 3/4" threads.

Its so you can thumb tighten it easier.

 

[MANDATE]

I think the confusion regarding the thread sizes is brought about by the terminology.
1/2 in tap connectors have a thread of around 3/4 inch diam.
The 1/2 inch in refers to the inside diam of the pipe, when I say pipe I mean the steel pipe used for water/steam installations.
I think you'll find a 3/4 in tap connector has thread of 1.000 inch.

 

[sterose]

You are correct MANDATE.

I apologise to all, if I didnt make myself clear.