Sealed system - how to add water/pressure?

Zab

Hi, been having some trouble with the heating here and any help would be greatly appreciated.

The radiators on the second floor of the house are not getting fully hot, and are varied from partially hot to no heat at all. Bleeding them releases foul smelling air but no water. I have not seen water come out of the bleed valves in years, although the system has been working to an acceptable degree during this time.

Reading around the internet I saw a suggestion that I add water to the expansion tank by "opening the tap above the boiler". I have no such tap though, so that may have been for a different type of system.

I've attached picture of the boiler room. I assume A is the expansion tank and its presence is why I'm assuming I have a sealed system. What is tank D? I guess H is the pump? I don't know what B and C are, and I've labelled the taps in case anybody wants me to turn one of them.

Honestly, I'd like to know what I should be doing assuming everything was "normal", however I have to admit that things have gone a bit strange the past few days. All the upstairs radiators started making noise while they were off a couple of nights ago, sounding as if they were emptying (although I'm not sure that's what was actually happening). The next day, when the heating came on, the radiators downstairs and then a lot of the pipes upstairs started making noise. The downstairs radiators got fully hot and the upstairs ones partially hot. Today the upstairs ones are worse, but downstairs is still going strong.

Any points welcomed, particularly just what I should be doing to add water to the system even ignoring the recent events.

Buford T Justice

You may have a filling loop in the hot press, perhaps you can post a pic of this?

Have you two expansion vessels here?

Zab

I'm not sure, but I'll check it out tomorrow and post pictures if there is one.

A and D are different tanks, yes. D is close to the ground whereas A is above the boiler.

Zab

Okay, went to the hot press but didn't find anything unusual, took some photos which I can post if needed.

However, I think I've found what we're looking for. It's labelled I in the attached picture, which also contains an mspaint of the boiler system with the same labels as the previous picture. Am I correct?

dollyk

I remember having this problem, if i remember correctly when the plumber came, he went to the red cylinder and used a bicycle pump to put the pressure back into the system. ???? there was a little valve oh the side for the pump..

Buford T Justice

dollyk wrote: »

I remember having this problem, if i remember correctly when the plumber came, he went to the red cylinder and used a bicycle pump to put the pressure back into the system. ???? there was a little valve oh the side for the pump..

If the EV's are faulty then yes, but its not the issue here.

It does look like that's the filling valve OP, but it is quite grotty there to see.....

But then, why do you have an expansion vessel on the mains going into the system?

Zab

Fingers McGee wrote: »

But then, why do you have an expansion vessel on the mains going into the system?

It's past the valve for the mains though, so assuming that valve is closed it's just another part of the sealed system.

I'll try adding some water tomorrow. Thanks for all the help.

Zab

Okay, an update on this.

I'm fairly convinced at this point that 'I' in the second picture above is the filling loop I'm looking for. It may not be clear in the picture but the part to the left is a gauge, I assume pressure, but due to its position I can't read it (that black part on the right is the boiler).

However, when I went to open it I found that it was already open, which was obviously disappointing. I have no idea how long it has been open for. Anything from one year to thirty-five years. I know that nobody who lives here has ever touched it.

Assuming that the part of the left is a gauge, is there even any check valve in the picture? Could there be a check valve in the same part as the gauge?

Thinking back I've realized that, apart from the debatable pressure we've had for years, the latest problems started when the water mains pressure dropped and then started being cut off. Since then our upstairs radiators have been draining over night and refilling when the mains came back on.

My current thoughts are that either:
a) They've been draining into the mains
b) There's a leak in the primary hot water circuit that's been masked by this valve being open

I'd be annoyed if it was A as it means the plumber must have been incompetent.

One more thing: I'm told that there's an electric device called a "mini valve" on the pipes leading to the upstairs radiators (these are controlled by a separate thermostat). Through internet research it appears that this is local lingo for a motorised/actuated valve? i.e. this is what allows hot water to the radiators upstairs (and hot water is making it up there). It isn't an anti-draining device or anything? I have to break some molding to get at it so I'd rather not if at all possible.

Thanks for all the help so far.

Buford T Justice

It does sound like the water is backfilling into the mains, which is dangerous.

The Motorized valve can be doing anything, it depends on what its wired to.

Zab

Fingers McGee wrote: »

It does sound like the water is backfilling into the mains, which is dangerous.

Gah, okay I've closed the valve overnight while the mains water is shut off. If the radiators don't empty tonight I'll have to replace it will a newer backflow prevention valve.