Leaking mains across the PHEX??, maybe shut off the mains cold where it enters the boiler for the "day" and open a hot tap, the flow switch shouldn't detect any flow and prevent the boiler from firing in DHW mode. But one would think the boiler pressure would rise if it is leaking across the PHEX.
Central Heating Nightmare - Air in System Daily
- Thread starter Cellophaneskies
- Start date
Leaking mains across the PHEX??, maybe shut off the mains cold where it enters the boiler for the "day" and open a hot tap, the flow switch shouldn't detect any flow and prevent the boiler from firing in DHW mode. But one would think the boiler pressure would rise if it is leaking across the PHEX.
How long have you left the boiler off for the air to settle and rise to the top?
Curious why the air might be staying in small bubbles, looking it up seems like inhibiter can do that on purpose to stop large pockets of air forming. if you tried a new inhibitor maybe flush and try with none. Maybe its a combination of multiple inhibiters types doing something. I'd drain and fill the system a few times until its just clean water and see what happens
For the first three of four years being here I didn’t really touch the system apart from running it so I know what the symptoms elevate to. The rads all jsut get lukewarm, they don’t really output any heat to be worth a damn.
I’ll have the heating running all evening and need a jumper. Rooms wont feel heated when you walk in.
You might touch the radiator and think ‘that’s hot’ but it isn’t actually heating the room. It’s like the flow through it is slow. The radiator is heated but it isn’t projecting into the room.
When I do my dance of flushing, the radiators will be so hot you can’t touch them for longer than a brief touch- they would melt the skin off your hand. You can feel hot air blasting into your face if hold it over them.
If I leave the system and don’t mess bleeding it, you barely feel hot air rising. You can hold your hand ok the rads for a few seconds. The very first thing complaint I had about the heating was that the bottom of multiple radiators doesn’t get hot- you could hold your hand on there for minutes. And lots and lots of clicking and sloshing air noise, so much it would wake me up.
It was also the same with a previous boiler which is why I don’t really think it’s boiler related.
when i said how long left i mean in terms of the air being small bubbles how long the system has been off to allow the air to rise to the top and form a normal single air bubble at the top. If its all day and the air stays suspended in the water that must be a symptom of something specific as its not normal by the laws of physics. Does it make no difference how long its been off?
You say flushes but do you mean fully draining and refilling? Do you always use inhibitor? I'd try without any and see it
After you've managed to get it all hot have you noticed which radiator gets cooler first, that might give a clue
You say flushes but do you mean fully draining and refilling? Do you always use inhibitor? I'd try without any and see it
After you've managed to get it all hot have you noticed which radiator gets cooler first, that might give a clue
That’s a bit difficult to quantify, the speed at which it gets worse. During winter it’s usually only off during the day, overnight. It’s left unused over summer. I’ve ordered some Bluetooth heat sensors so I can measure how fast it heats rooms and get some data on the speeds for comparison.
Usually, once it works ok, the next day it worse again, and about three weeks is where it gets to the point where it’s pretty much useless running it/I have to run for hours to get ‘warm’, not even ‘hot’.
It has been fully, entirely drained three or four times since I’ve been here. I’ve had all rads off one by one and flushed them with a hose. I bleed it so much that there must be almost no inhibitor in there right now. When I drained it myself o refilled with a different inhibitor brand to that the heating company uses, no difference.
The extension radiator is usually the one that suffers most first. Then the living room. Then bedroom 3. They will all degrade but those three- put it this way, it was just running for 45 minutes and the extension radiator I could hold my hand in the middle indefinitely - lukewarm. Top of rad quite hot but room doesn’t feel heated.
So the furthest away first, like if the pump was weak. I guess if the system is full of air the aerated water will leave the pump with less force, like spongy brakes in a car with air in the system, the bubbles compress so the forward momentum is lost.
The pump will also mash up the air into the bubbles you are finding. But do they rise through the water given some time or stay suspended in the water? If you come home from work after its been off and bleed before its on is it better? You're not bleeding with the pump on are you?
The pump will also mash up the air into the bubbles you are finding. But do they rise through the water given some time or stay suspended in the water? If you come home from work after its been off and bleed before its on is it better? You're not bleeding with the pump on are you?
Is the system pressure normal and the automatic air vent new? They're only cheap so its worth getting a new one. I had a funny one with my airvent, I changed it for new and noticed it came with a plastic tap sticking out of the bottom which i puzzled over not sure if it was to be left in or removed. In the end decided it was just for transport to stop the float flying around and should be removed otherwise the float can't come down when there is air in it. So i took the old vent off and found the previous installer had left the tab in. Caused more doubts for me if i was right but i took mine out and its fine. Maybe it partly worked with the tab still in i dont know, the vent had the signs of water leaking out the top so maybe it didnt work with the tap in and that caused it to fail. Anyway moral of the story is you might have a new vent but it still might not be venting
So its probably not significant that you'll find the colder ones at the furthest point first rather than its a clue that there is a air leak at that furthest point
makes sense that more air is upstairs, and BR is noticeably more than the others? or is B3 similar?
Why do you turn off the rads to bleed? You need the water to be able to move around to fill the space left by the released air. Start downstairs and work your way around the house leaving the rads on, with the system off. Do it after the system has been off for the day to give the bubbles time to rise
Hi
Just about to start work so I’ll reply to all your points later. But I do have to bleed with the pump on. If I bleed with it off, I just get water out. Nice gentle trickle. If I bleed with it on, I get the fizzing and farting water. I would think perhaps this is water I’m introducing by the act of bleeding, but as the water farts out, you can feel the rad you’re working on getting hotter! With enough patience the system will then get screaming not. If I do this without it running I don’t get the same impact.
I turn off all rads aside from LR and EXT, and the one I, bleeding, as this seems to result in the most fuzzy air coming out. It’s as if the worst impacted water is in these two rads, and isolating only these two forces the water around faster for me to get to the fizzy air. If I do it with app rads on I get less fizzy water out and the process takes longer or doesn’t give me any results.
I sound like a madman but it’s learned behaviour, doing this results in a house thst feels like a tropical jungle after 20 mins, versus running heating for an hour and being mildly warm at best!
The red I get the most fizzy water from varies. It has changed over the years. For a long while it was only BR. But more recently I’m having way more luck with B3. Thr fizzy air will shoot out like a rocket, you’ll hear whooshing and spitting. Sometimes it’s rhythmic, like whoosh trickle whoosh trickle whoosh trickle. But eventually it will improve to the point where I just get a water trickle with no fizzing or spitting, and then the whole system works great - until it’s been off for a few hours!
I might upload a video so I can demonstrate what this sounds like.
I’ve tried running it without LR,BR,EXT, B3 in the loop ie I turned off lock shield and thermostats to isolate the rad from the system to see if they’re the fuses of the air or if they in some way make it worse. No difference - the system seems problematic no matter how many rads it is heating.
was just thinking that, it must be losing water but then drawing air in when running. Faulty pressure relief valve?
Is water dripping out of the pipe at the back of your house?
Yes I’ll need to re add water as appropriate
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