Draining radiators on a communal heating system

[PhillipDavies]

Hi all,

I have a small plumbing job to do for which I need to drain the radiators in my property. There are only two radiators, that are fed by a communal boiler, and pass through an immersion heater. I have already identified the isolation valves for the primary flow and the return to my property. I don't have access to the communal boiler, or the specifications for it, and the building manager hasn't responded to my e-mails in months.

What I need to know is, how do I isolate my radiator system from the communal boiler in order to drain the radiators and work on the pipes, and then safely open the flow again once the work is done?

I have no pressure gauge in my property, is pressure something I need to worry about? Or is it as simple as turning off the flow and return to my property, draining the radiators, doing the work, and then turning them on again and bleeding the radiators until they refill?

I'd be very grateful to anyone that can help with this query.

 

[ShaunCorbs]

Any chance of a picture of where the communal supplies come in eg the valves

 

[PhillipDavies]

Any chance of a picture of where the communal supplies come in eg the valves

Thanks for your reply!

Sure! Flow and return as labelled.

 

[ShaunCorbs]

Just turn these off and you should be fine test it’s off before you start doing anything

as for filling it should be an automatic filling unit so you should be fine on that

 

[PhillipDavies]

Just turn these off and you should be fine test it’s off before you start doing anything

as for filling it should be an automatic filling unit so you should be fine on that

So its as simple as turning them off, draining the radiators, doing the job, turning them back on and bleeding the radiators?

 

[SJB060685]

You say it should be an auto top up unit Shaun but I wouldn't be surprised if not 😁.

 

[ShaunCorbs]

You say it should be an auto top up unit Shaun but I wouldn't be surprised if not 😁.

soon find out, I would think it would be low on pressure by now anyway

 

[ShaunCorbs]

So its as simple as turning them off, draining the radiators, doing the job, turning them back on and bleeding the radiators?

correct

 

[PhillipDavies]

Just turn these off and you should be fine test it’s off before you start doing anything

as for filling it should be an automatic filling unit so you should be

correct

Thank you so much for your help!

 

[SJB060685]

soon find out, I would think it would be low on pressure by now anyway

It should have an auto top up unit yes and probably does. I said that based on the image of pipes, they look hastily plumbed in.

 

[PhillipDavies]

It should have an auto top up unit yes and probably does. I said that based on the image of pipes, they look hastily plumbed in.

Yes they were rather hastily plumbed in by the building management about 3 months ago. They are renovating the block, and I think thats why they are to busy to respond to me at the moment. Thank you for your help as well!

 

[SJB060685]

Yes they were rather hastily plumbed in by the building management about 3 months ago. They are renovating the block, and I think thats why they are to busy to respond to me at the moment. Thank you for your help as well!

I've not really helped you as Shaun already covered the basics. I simply joined in and commented that one shouldn't assume. Commercial, industrial and communal systems are a different ball game to your average domestic systems and not everyone undertaking the work is qualified or competent.
You're in good hands on the forum though 👍

 

[PhillipDavies]

correct

Hi again,

Sorry if I am asking stupid questions, but I want to make sure I fully understand this process before I carry it out.

If it turns out there is an automatic system for maintaining pressure, how do I safely refill the heating system after doing the work?

Do I need to worry about flooding the communal system with air, or will the automatic pressure system handle that? I.E, can I re-open the flow and return valves at the same time, or would I need to open only the flow, bleed out all the air I can, then open the return?

How do I safely refill the heating system, as isn't it dangerous filling the system with hot water and having the bleed valves open? The water comes in hot from a boiler I don't have access to.

Thanks for your help so far, if you know the answers to these questions I would appreciate it.

All the best,
Phil

 

[SJB060685]

If it has an auto top up system then that unit will fill the system back up to a pre set pressure.
Once the work has been completed simply open up the valves, let the system top up and bleed it through.
The system should have means of expelling any air that might enter when you reopen the valves.
With regards to filling your system with hot water I wouldn't worry, its quite mild at the moment, I cant imagine the boiler is running flat out for heating and your leg of the system will most likely be cold.

 

[PhillipDavies]

If it has an auto top up system then that unit will fill the system back up to a pre set pressure.
Once the work has been completed simply open up the valves, let the system top up and bleed it through.
The system should have means of expelling any air that might enter when you reopen the valves.
With regards to filling your system with hot water I wouldn't worry, its quite mild at the moment, I cant imagine the boiler is running flat out for heating and your leg of the system will most likely be cold.

Thanks for your reply! Good to know I don't have to worry about filling the communal system with air.

I tested the temperature today, I opened the TRV fully, and the pipes became too hot to touch in minutes, so I am concerned.