Gurgling and air in central heating

[jim843]

If you read .5 bar on the pressure gauge at the boiler then the pressure at the highest point of the system will be less, perhaps no water up there at all and yes air can enter.
Would air being admitted into the system cause the pressure to rise? Yes it would.

Pressure is now between 2.2 and 2.5 (I've not seen it drop below 2.2).

There's defo water in the rads at the top of the house.

When I pressurised to a higher bar I got the tado app to open all valves so everything was open. I only forgot about the two rads in the house in the hall that have normal TRVs.

 

[jim843]

Would air being admitted into the system cause the pressure to rise? Yes it would.

So the pressure never seems to drop or rise over time.

That said, I haven't looked too much at the gauge going up as I have been looking for drops and bleeding the bathroom rad.

 

[SJB060685]

2.2 bar cold?

 

[jim843]

2.2 bar cold?

Not stone cold, cool-ish. Because the heating has been on because of cold weather it's never quite cold.

As an example, when the pump comes on the pressure drops to about 2 bar. When the pump switches off, it goes to 2.2 or slightly higher.

Based on what @johntheo said I checked the flow and return pipes...

Facing the boiler, the left most pipe seems to be the flow. The filling loop goes from the cold water supply to the return. The return has the magnetic filter on.

I checked the schematics in the installation and service manual and this seems to match.

 

[Deleted member 123817]

How often have had to top it iup?

 

[jim843]

How often have had to top it iup?

Never.

I bleed the air. That’s it.

 

[Deleted member 123817]

So after bleeding the air off each time the pressure returns to normal ?. I know it doesn't add up but could/can you remove the filling loop to absolutely rule it out.

 

[jim843]

So after bleeding the air off each time the pressure returns to normal ?. I know it doesn't add up but could/can you remove the filling loop to absolutely rule it out.

I’m not sure that the pressure rises. I will try and monitor.

It’s hard because it fluctuates a little bit. Baxi engineers said this is normal.

Not sure how to remove the filling loop exactly. Would I have to drain the system?

 

[Deleted member 123817]

There should be a flexible hose somewhere where it connects to the boiler return with isolating valves or can you post a photo of the isolation valve you described previously?

Do mean by PG fluctuations that it changes fairly rapidly while watching it and have you watched it for any unusual behaviour while using hot water?

 

[jim843]

There should be a flexible hose somewhere where it connects to the boiler return with isolating valves or can you post a photo of the isolation valve you described previously?

Do mean by PG fluctuations that it changes fairly rapidly while watching it and have you watched it for any unusual behaviour while using hot water?

Will see if there are isolating valves behind.

The pressure only drops/rises when the pump goes on/off. Not during heating.

Haven’t checked when using hot water but will check tomorrow.

 

[jim843]

@johntheo while I was looking I noticed this.

Also some of the copper pipes into the boiler have this.

Anything to worry about?

 

[John.g]

Will see if there are isolating valves behind.

The pressure only drops/rises when the pump goes on/off. Not during heating.

Haven’t checked when using hot water but will check tomorrow.

That is the filling loop with a non return valve where shown and a isolating valve where shown on the other end, ensure the isolation valve is closed "across (at right angles to) the pipe" then just slacken the flexible hose where attached to the NR valve but do not remove it, when slackened a few turns water should only dribble out for a few seconds and then stop.
There may be another isolation valve on top of the NR valve but I don't think so, if there is, shut it as well

 

[John.g]

@johntheo while I was looking I noticed this.

Also some of the copper pipes into the boiler have this.

Anything to worry about?

I dont't think so, these look like isolating valves for the boiler flow/return.

 

[jim843]

That is the filling loop with a non return valve where shown and a isolating valve where shown on the other end, ensure the isolation valve is closed "across (at right angles to) the pipe" then just slacken the flexible hose where attached to the NR valve but do not remove it, when slackened a few turns water should only dribble out for a few seconds and then stop.
There may be another isolation valve on top of the NR valve but I don't think so, if there is, shut it as well

Ok, I’ll try this tomorrow along with the hydrogen check!

Do you think air could be somehow being pulled into the system here?

If so, would it be the loop or the NRV?

 

[John.g]

No, I think it highly unlikely because even if the flexible hose is perished/holed then with a sealed system the pressure should still keep the NR valve shut. I also find it difficult to imagine that you are pulling in air anywhere in the volumes that you are getting especially if the boiler pressure is normally 1bar or higher. Lets hope in one way that its hydrogen!.