Air in new central heating system.

CitizenFloor

Not sure what the discharge is. Is it the little nub on either side of the pump in the pic? What is the expected outcome? I don't know what the valve does, so I don't know how it can determine power output per zone.

I have to say, thanks again for all the help if troubleshooting!

John.G

Yes, its the highlighted one on the right, just briefly turn this a 1/4 turn clockwise and observe the watts, I expect 7W. You can't use this to determine the outputs but I will give you a calc that will.

CitizenFloor

John.G wrote: »

Yes, its the highlighted one on the right, just briefly turn this a 1/4 turn clockwise and observe the watts, I expect 7W. You can't use this to determine the outputs but I will give you a calc that will.

Sound, will do when home from work.

So, what I expect to happen is:

1 - Turn the pump on, leave the boiler switched off. The pump will spin up to 7W.

1 - 1/4 turn clockwise on the valve briefly, and the wattage should remain at 7W.

John.G

Yes but it doesn't matter how many zones are on, "just 1/4 turn clockwise on the valve briefly",
we know that the reading is 7W with all zones apparently shut so the reading should not change when you shut the valve.

Equally interesting, can you take the readings (forget about shutting the valve after the above test) for zone1 only, zone2 only, zone3 only, then zone1+zone2, zone1+zone3 and zone2+zone3.

CitizenFloor

John.G wrote: »

Equally interesting, can you take the readings (forget about shutting the valve after the above test) for zone1 only, zone2 only, zone3 only, then zone1+zone2, zone1+zone3 and zone2+zone3.

That is exactly the testing I was talking about....Ill be doing that later. Hopefully will identify the zone that is always on.

Wearb

CitizenFloor wrote: »

Not sure what the discharge is. Is it the little nub on either side of the pump in the pic? What is the expected outcome? I don't know what the valve does, so I don't know how it can determine power output per zone.

I have to say, thanks again for all the help if troubleshooting!

Not so sure I'd touch those valves. They are notorious for leaking when disturbed.

John.G

They should be OK when new but I certainly wouldn't touch them if > a few years old.

CitizenFloor

Its brand new, but for the sake of risk vs reward, I might just test the zones as outlined first, try identify the problem that way, and assess from there....

John.G

Yes, I don't think that its pumping much at 7W but the other tests will show it up. Here are my pump powers at various PP settings, for interest.

CitizenFloor

John.G wrote: »

Yes, I don't think that its pumping much at 7W but the other tests will show it up. Here are my pump powers at various PP settings, for interest.

Is it possible that 7W is just its idle state in PP2. And 5W in Auto?



I looked up the product, and it says its a 5w-47w pump, and I am wondering is it just never goes below 5w by design.

John.G

I think we are splitting hairs here, here are my readings, with a 4M PP setting and discharge valve opened,14W...... and with valve closed, 7W.

CitizenFloor

Okay, at the risk of getting down into the weeds, let me make sure I understand.

I think what you are saying that in your own system is on a 4M PP (4 meter proportional-pressure setting??) setting. The wattage is 14w with the valve open, and 7w with the valve closed.
If that is correct, I am wondering if it matters that my setting is PP2. I am not sure if that is a 4M PP setting too, or if that even matters. Or will it just be useful to see the results.

The question I mentioned a couple of posts ago was based on the pump specs attached. It says the minimum output is 5W. Is it possible that it just never goes below that, perhaps to maintain some sort of pressure in the system? Or do all of these pumps definitely and completely stop (i.e. 0w or a blank screen) when not being called for heat?

....Will do the various tests being discussed later!

John.G

The PP setting has a huge influence on the circulation flowrate, unfortunately a lot of the well known brands maximum PP setting is far too low and the Tucson doesn't win any prizes as PP2 setting is fixed at 3.2M, if I set my PP setting to that (3.2M) it would only use 9W when my 4M setting gives 14W and more or less the flowrate I require with a lot of TRVs throttling in. Any pump should be able to provide a PP setting high enough to give you the required flowrate with all zones/TRvs opened up it will then throttle in as the zones or TRVs close in. You have a very low head system and that's why 3.2M should be OK (we will see what tests show). My pump can provide PP settings from 0.5M to 6M in 0.1M increments so will satisfy most systems if running in PP mode. Almost all pump PP mode operation will keep ramping down until it sees its PP set point at "1/2" so if you have a setpoint of 3.2 and all zone valves shutoff or you shut the discharge valve then it ramp down until it "sees" (by smart calculations) that the head is 1.6M, (3.2/2). My 4M PP setting will cause the pump to ramp down to 2M and so on. NO, they certainly won't stop or present a blank screen, they aren't that "smart". Maybe who ever installed yours thought that they were!.

CitizenFloor

John.G wrote: »

NO, they certainly won't stop or present a blank screen, they aren't that "smart". Maybe who ever installed yours thought that they were!.

This is what I don't understand. What are we expecting the pump to do?

Right now, with all my zone valves off/nothing calling for heat, the pump is ticking over at 7w - PP2 (3.2M).

If it wont stop, go to 0w, or present a blank screen, what should I expect it to do when I ask my electrician to fix it?

I thought the fact that it was always running was the problem.

John.G

Yes, that is the problem but ANY pump smart or otherwise will keep running if its still getting a constant run signal. As explained before, the pump should only run if any one (or all) of the zone valves are opened, once the last zone valve shuts then the pump should stop. In your installation there is also some interface with the house frost stat, the electrician should be au fait with this, just ask him or show him the schematic I posted, if he was sub contracted by the plumber then he should be able to sort out the problem easily.

CitizenFloor

John.G wrote: »

Yes, that is the problem but ANY pump smart or otherwise will keep running if its still getting a constant run signal. As explained before, the pump should only run if any one (or all) of the zone valves are opened, once the last zone valve shuts then the pump should stop. In your installation there is also some interface with the house frost stat, the electrician should be au fait with this, just ask him or show him the schematic I posted, if he was sub contracted by the plumber then he should be able to sort out the problem easily.

Sound. Wires crossed. I thought you were suggesting it should never stop.

CitizenFloor

Called the electrician, and the plumber there. Electrician said the plumber told him to wire it with a constant supply. The plumber said that on Auto, it will stop after the water cools down (I assume that this is the overrun feature. I'm testing this one auto now. I initially tested it on PP2), and it will speed up when more water is needed.

He also said to leave the auto bleed valves open again, all the time. To constantly bleed air. Which is annoying because I don't want air getting into the system in the first instance.

John.G

I'm afraid not, that pump has to be wired in like any conventional circulating pump, period. What readings are you getting on Auto with different zones opened.? you can then compare it with the readings that you will be taking in PP2 mode.
If you continue to leave the pump running with the zone valves closed then you will only add to the air problem.

I would agree with leaving the auto vents open for the reasons that I gave in another post.

CitizenFloor

Will test in a little while. Checking if the pump stops after a while on auto. I was told it would. As of right now, it's still 5w. Everything is off/closed.

No problem in leaving the bleed valves open if it's safe to do so, but not for the express purpose of releasing air that should not be getting in.

Wearb

CitizenFloor wrote: »

Will test in a little while. Checking if the pump stops after a while on auto. I was told it would. As of right now, it's still 5w. Everything is off/closed.

No problem in leaving the bleed valves open if it's safe to do so, but not for the express purpose of releasing air that should not be getting in.

I could be wrong as John is very good on this sort of thing, but how does the pump monitor the requirements if it doesn't run at some level. eg If it was to stop completely when all zones were off, how would it know when a zone opened if it wasn't running at all?

CitizenFloor

John.G wrote: »

I'm afraid not, that pump has to be wired in like any conventional circulating pump, period. What readings are you getting on Auto with different zones opened.? you can then compare it with the readings that you will be taking in PP2 mode.
If you continue to leave the pump running with the zone valves closed then you will only add to the air problem.

I would agree with leaving the auto vents open for the reasons that I gave in another post.

Wearb wrote: »

I could be wrong as John is very good on this sort of thing, but how does the pump monitor the requirements if it doesn't run at some level. eg If it was to stop completely when all zones were off, how would it know when a zone opened if it wasn't running at all?

I wouldn't know to be honest, John would need to comment.

I also remembered that when I turned the pump & boiler off for the day, I had set it back to Auto. When I came home (after about 10hours) and turned it on, it was 5w on Auto, so I don't think it will ever stop on the auto setting. The water was cool at that stage.

I attached the testing of the zones. It makes more sense to me that PP2 ups the wattage the more zones are open.



During testing, I noticed some unusual behavior with the zones turning off, I had not noticed it before. I am hoping this may be the cause of the issue. I know I said earlier that the valves were working as expected, but I may have been wrong.

When I turn on a zone.

1 - My phone says the zone is on.

2 - A light comes on the programmer in the kitchen to show a zone is on.

3 - A light comes on the zone valve, to show that its open and water is released into the zone.

1 - The pump wattage goes up to move more water to the zone (based on the attachment).

But, I noticed that if two zones are on together. Say for instance Downstairs & Hot Water, when I turn off Hot Water, or vice versa.

1 - My phone says the zone is off.

2 - The light on the programmer says the zone is off.

3 - The light remains on the zone valve, to show that its open and water is released into the zone.

4 - The pump wattage remains the same as if two zones are open. So instead of dropping down to indicate 1 open zone, it indicates two are open as the wattage is higher.
It remains like this until the remaining zone is shut off, at which point both valves close.



Its the same regardless of which zone is turned off. If two are on together, and one is turned off. The valve of the one that is turned off remains open.

Surely this is related to a wiring issue?

Plumber & Electrician are coming Monday.

John.G

Wearb wrote: »

I could be wrong as John is very good on this sort of thing, but how does the pump monitor the requirements if it doesn't run at some level. eg If it was to stop completely when all zones were off, how would it know when a zone opened if it wasn't running at all?

It would be a bit ironical if every replacement circ pump in the country or indeed the whole of Europe was running away merrily for 24/7 since you can only install A rated smart pumps now and consuming power when they should be switched off!.
OK then I'll try and explain it in simple terms, but to answer Wearb above, the pump will know that a zone has opened because the zone valve STARTS (and stops) the pump when it opens the same as it always did and will. The zone valve closes, the pump stops. OK.
Now the pump microprocessor only looks at the power consumed so it must use a reference curve to know where it is and for every single point on that reference curve there will be a corresponding power demand. To keep it simple just assume that the pump is connected to a water supply with a isolating valve and short pipe on the end. going to drain.
again assume my pump is set to run with a with a PP setting of 4M.
From the pump curves reference:
2M = 0.00LPM = 7W
2.5M = 5.75LPM = 12W
3.0M = 11.5LPM = 15W
3.5M = 17.25LPM = 26W
4.0M = 23.00LPM = 37W

Now the pump starts up with the valve fully shut, the reference power required is 7W and the pump will start increasing speed until it sees a power consumption of 7W and will the stop increasing speed so you now have a pump running with a 2M head with no flow.
You now open the valve a little so the actual power will decrease and the pump speed will again increase and depending on the valve opening will keep increasing until it sees 12W which is a flowrate of 5.75LPM at 2.5M and so on.
There are literally dozens of reference curves and the microprocessor knows the power required for every point on them as well so the pump speed will ramp up or down depending on valve opening zone valve opening or TRVs throttling etc.
When we get some real figures re the Tucson we can look at them.

CitizenFloor

I'm going mad Ted.

John.G

I told you they were smart Ted, but still have to stopped and started. will revert later.

CitizenFloor

John.G wrote: »

I told you they were smart Ted, but still have to stopped and started. will revert later.

Sound, I posted the real values and some results of testing above, in case you missed it!

John.G

CitizenFloor wrote: »

I wouldn't know to be honest, John would need to comment.

I also remembered that when I turned the pump & boiler off for the day, I had set it back to Auto. When I came home (after about 10hours) and turned it on, it was 5w on Auto, so I don't think it will ever stop on the auto setting. The water was cool at that stage.

I attached the testing of the zones. It makes more sense to me that PP2 ups the wattage the more zones are open.



During testing, I noticed some unusual behavior with the zones turning off, I had not noticed it before. I am hoping this may be the cause of the issue. I know I said earlier that the valves were working as expected, but I may have been wrong.

When I turn on a zone.

1 - My phone says the zone is on.

2 - A light comes on the programmer in the kitchen to show a zone is on.

3 - A light comes on the zone valve, to show that its open and water is released into the zone.

1 - The pump wattage goes up to move more water to the zone (based on the attachment).

But, I noticed that if two zones are on together. Say for instance Downstairs & Hot Water, when I turn off Hot Water, or vice versa.

1 - My phone says the zone is off.

2 - The light on the programmer says the zone is off.

3 - The light remains on the zone valve, to show that its open and water is released into the zone.

4 - The pump wattage remains the same as if two zones are open. So instead of dropping down to indicate 1 open zone, it indicates two are open as the wattage is higher.
It remains like this until the remaining zone is shut off, at which point both valves close.



Its the same regardless of which zone is turned off. If two are on together, and one is turned off. The valve of the one that is turned off remains open.

Surely this is related to a wiring issue?

Plumber & Electrician are coming Monday.

Re wiring fault: Well spotted, Yes, I have seen this before, it's probably because a common live is being used so when two zones are switched in there is a back feed back from one switch to the other so switching one off does nothing, electrician should be able to resolve.
Whatever about any issues you may have, I can say from your power readings that you have a well plumbed low loss system.
The power indicates that one zone flows ~ 14.2 LPM, two 18.3 LPM and three 22 LPM.

CitizenFloor

John.G wrote: »

Re wiring fault: Well spotted, Yes, I have seen this before, it's probably because a common live is being used so when two zones are switched in there is a back feed back from one switch to the other so switching one off does nothing, electrician should be able to resolve.
Whatever about any issues you may have, I can say from your power readings that you have a well plumbed low loss system.
The power indicates that one zone flows ~ 14.2 LPM, two 18.3 LPM and three 22 LPM.

Million dollar question - can you guess/speculate/tell me if this could be causing the pump to run constantly?

My plumber says the pump should be turning off automatically. Its not.

Is it possible that the wiring issue is causing the pump to remain on constantly, by keeping a valve open periodically, because it only happens in the situation I described above, until all zones are turned off.

I ask the question because even when all valves are definitely closed, the pump keeps ticking over (5w on auto, 8w on PP2) anyway.

John.G

CitizenFloor wrote: »

Million dollar question - can you guess/speculate/tell me if this could be causing the pump to run constantly?

My plumber says the pump should be turning off automatically. Its not.

Is it possible that the wiring issue is causing the pump to remain on constantly, by keeping a valve open periodically, because it only happens in the situation I described above, until all zones are turned off.

I ask the question because even when all valves are definitely closed, the pump keeps ticking over (5w on auto, 8w on PP2) anyway.

"My plumber says the pump should be turning off automatically. Its not."
Forget that, its wrong and history.

Pump running constantly due to above wiring fault.
Its possible but improbable "Electrician said the plumber told him to wire it with a constant supply" so all I can say is that the electrician has to sort out (1) the wiring mix up that's keeping the two zones opened and (2) ensure that the pump is wired in parallel from the zone valve(s) end switches as per "my" schematic.

CitizenFloor

Okay, I was just in the attic doing the water test on the vent. I had a measuring glass under the vent on a board, the water was still.

When I turned all or some zones on, the water either didn't move, or some bubbles came out.

When I turned all or some zones off, water was sucked into the vent.

I tried on both Auto & PP2...I think PP2 was more severe but the same thing happened for both.

This could be it, right? Perhaps a T into cold water filter, or test with a cork over the weekend?

Plumber coming on Monday, will ask him to take a look. Electrician actually coming on Tuesday. Will ask him to fix

John.G wrote: »

(1) the wiring mix up that's keeping the two zones opened and (2) ensure that the pump is wired in parallel from the zone valve(s) end switches as per "my" schematic.

Wearb

John.G wrote: »

It would be a bit ironical if every replacement circ pump in the country or indeed the whole of Europe was running away merrily for 24/7 since you can only install A rated smart pumps now and consuming power when they should be switched off!.
OK then I'll try and explain it in simple terms, but to answer Wearb above, the pump will know that a zone has opened because the zone valve STARTS (and stops) the pump when it opens the same as it always did and will. The zone valve closes, the pump stops. OK.
Now the pump microprocessor only looks at the power consumed so it must use a reference curve to know where it is and for every single point on that reference curve there will be a corresponding power demand. To keep it simple just assume that the pump is connected to a water supply with a isolating valve and short pipe on the end. going to drain.
again assume my pump is set to run with a with a PP setting of 4M.
From the pump curves reference:
2M = 0.00LPM = 7W
2.5M = 5.75LPM = 12W
3.0M = 11.5LPM = 15W
3.5M = 17.25LPM = 26W
4.0M = 23.00LPM = 37W

Now the pump starts up with the valve fully shut, the reference power required is 7W and the pump will start increasing speed until it sees a power consumption of 7W and will the stop increasing speed so you now have a pump running with a 2M head with no flow.
You now open the valve a little so the actual power will decrease and the pump speed will again increase and depending on the valve opening will keep increasing until it sees 12W which is a flowrate of 5.75LPM at 2.5M and so on.
There are literally dozens of reference curves and the microprocessor knows the power required for every point on them as well so the pump speed will ramp up or down depending on valve opening zone valve opening or TRVs throttling etc.
When we get some real figures re the Tucson we can look at them.

Thanks for that John. I should have elaborated. I was assuming that the pump had been wired directly to the programmer, seeing that it had power with zones off.

John.G

CitizenFloor wrote: »

Okay, I was just in the attic doing the water test on the vent. I had a measuring glass under the vent on a board, the water was still.

When I turned all or some zones on, the water either didn't move, or some bubbles came out.

When I turned all or some zones off, water was sucked into the vent.

I tried on both Auto & PP2...I think PP2 was more severe but the same thing happened for both.

This could be it, right? Perhaps a T into cold water filter, or test with a cork over the weekend?

Plumber coming on Monday, will ask him to take a look. Electrician actually coming on Tuesday. Will ask him to fix

Auto is useless, you will have to run on PP2 to get adequate circulation, carry out the Cork test on the vent and if no problems, then you have two choices, one is very messy as you will have to reposition zone valve3 onto the cylinder coil top entry leg and then combine the cold feed with the vent. The other choice is easier but the plumber would need to be happy with it and that is to leave the zone valve where it is, blank off the vent and just use the cold feed as is to take the expansion as well.

John.G

Re Zone valve wiring fault, if it is wired the way I think it is then if all three are wired the same way it would seem to me that you would have to switch off all three once they are all on together, your tests would indicate that this fault affects only two particular zones? In other words can you switch off/on one particular zone when all three have been on together?.

CitizenFloor

John.G wrote: »

Re Zone valve wiring fault, if it is wired the way I think it is then if all three are wired the same way it would seem to me that you would have to switch off all three once they are all on together, your tests would indicate that this fault affects only two particular zones? In other words can you switch off/on one particular zone when all three have been on together?.

Should have thought of testing that. Can't confirm at the moment. Ill test when I get home.

CitizenFloor

It's wired the way you think it is, John. For any zone to turn off, they all need to turn off. Didn't spot it earlier, because the zones are shown as powered off everywhere (Programmer, Phone etc.) except for the valve lights.

So I need to get the electrician to wire the valves properly, and wire the pump in parallel with the valves. I think the pump getting a constant power supply must have been a misunderstanding between plumber & electrician.Everything in the S Plan makes sense to me logically - https://www.plumberparts.co.uk/advice/heating-systems/s-plan-heating-system.
I am assuming the electrician should just be able to do some simple rewiring, with the cables that are already in place?

I carried out another test last night. The auto bleed valves had been open all day, and there was no air coming out. I checked the rads and there was no air. In order to satisfy myself that it wasn't just residual air in the system after the initial install, I set the system back to where it was before troubleshooting started. i.e. Auto on, Auto Bleed Valves closed, programmed for various zones to trigger throughout the day.
When I opened the auto bleed valve just now, a days worth of air came out. So 100% there is still air getting in.

Next test -
- Leave the auto bleed valves open for an hour (right now there is a constant trickle of air coming out).
- Bleed any air in the rads (I don't expect there is much, if any).
- Put the cork in the vent pipe.
- Close the auto bleed valves
- Let the system run on the program settings for another day.
- Open bleed valves again, and listen for air.
If there is no air, its more than likely the vent?

To be honest, I am hoping the constantly running pump is at least a contributing factor....if the cork doesn't resolve the issue, maybe the combination of fixes will.

John.G

Very good, the zone valve actuator indicating lights were very handy for that bit of trouble shooting, the zone vales have been wired I would think with each zone valve motor and its end switch being fed from the programmer, the end switch should have its own live supply, this supply can be the same to all three.
Re wiring the pump, the electrician should first check that the present boiler switched live is coming from the three zone valve end switches wired in parallel, the pump supply can then be taken from this live where it enters the boiler control box and before the boiler stats.

I came across a very very rough sketch that I drew (at the time) of the zone wiring problem that I found in a relations a good few years ago, I think it first came to light when the programmer fuse blew, I presume because this supply was now feeding the boiler fan motor and oil pump as well as just the zone valve motor of 10W or so.
I just sketched the motorized valve as a solenoid and when its energised pulls in (up) the end switch, you will get the gist of it when you see this masterpiece.

CitizenFloor

There was air in the system again, the vent was corked, and taped.....

Hanging my hopes on the constantly running pump. Will see how we go after Monday, when the electrician has done the rewiring.

CitizenFloor

The electrician is here now. He is saying that wiring the valves in parallel with the pump might cause and issue with the boiler stat tripping. He is suggesting putting a stat on the pump also but with a constant supply, so that it will pump when all valves are closed, until the water cools down sufficiently. The pump would still be working when all valves are closed, but only until the water cools down.

He said he could do it in parallel with the valves also.....is this just a matter of personal preference?

To be honest, I would like the pump to be off as soon as the valves close, but I don't want the stat tripping due to residual heat.

John.G

Have only got my iphone now for a few days so can't be too verbose..... Just ensure that the zone valves and pump are wired elites as per s schematic, forget the pp overrun for now as oil fired boilers rarely trip the hi limit stat and furthered even if you arrange/install a pump overrun it is useless unless you also install automatic by pass valve as well. So KIS, keep it simple.o

CitizenFloor

Okay, so its wired as per the S Plan.

The valves are now wired correctly, and the pump turns off when the valves shut. I have had all zones on for a while, and the hot water tank is just reaching 64 degrees....So if the hi stat is going to trip, it will happen when that shuts off, as its the last zone to come up to heat.

Plan on closing the auto bleed valves tonight, and checking for air tomorrow after work. Fingers crossed.

John.G

Very good,it will be interesting. Of course it should also go without saying that the boiler is switched off as well when the last zone valve closes, the boiler control stat may then operate at the boiler set point say 70c but the hi limit lockout stat which is set at - 113C should not operate

Oh yes you did say above that the pump does stop.

CitizenFloor

Balls.

It appears there is still air. I think it happens more when the hot water zone is on, at least that is when I notice it more, and the vent is on that circuit. So now that the pump is not running constantly, I might just leave the auto bleed valves open for a day or two, and the plug the vent and test.

I'm not done yet, but if nothing else, at least all the troubleshooting has helped resolve the valve wiring & pump issue.

CitizenFloor

Is it likely that air might be getting it at one of the pipe joints? I have checked all the joints possible...under floorboards, in the shed etc. No apparent leaks......

I'm also wondering if the system isn't balanced correctly, could that cause issues?

John.G

Relax, call this hour zero, yothen u have already established that it's more than likely that it's more than likely that air is being drawn through the vent.... So leave the cork in leave AAVs open and see how you get on, if the very w

CitizenFloor

Haha, I know I know....progress has been made.

Okay, I have a full tank of hot water, and the water zone is programmed off (I figure that is easier than getting into the attic all the time).

Upstairs & downstairs are programmed to keep the place heated as per the normal schedule.....I'll check for air tomorrow!

CitizenFloor

Okay, so the air is still there....even with with the Hot Water zone closed. I just had Upstairs & Downstairs zones opened since the 3rd. I have checked the auto bleed valves on a few occasions, and air is building up. After the systems had cooled last night, and everything was off, I bled all the rads and no air was present. There was air at the auto bleed valves this morning too.
For whatever reason my Hot Water zone theory was a red herring. I can hear the valves open automatically, from the hallway, a couple of times I heard a gurgle when the hot water valve opened, and maybe that skewed me.....

The positive is, I think that rules out the vent, and the constantly running pump.

This morning I closed Hot Water, and Upstairs zones, and left only Downstairs zone programmed for the day. Ill see if there is an air build up later. Then Ill do the same with the Upstairs zone tonight.

This needs to be taken with a pinch of salt, considering my track record, and while I test further. But, the last couple of nights I heard gurgling that *appears* to happen when the boiler kicks in (My hearing has gone sonic for any gurgling sound at this stage ). The main flow & return runs up via the chimney breast in the living room to the three valves. When its quiet I can hear some air moving through the pipes, and I think it might be when the boiler kicks on/pump speeds up. Problem is, I don't think its happening every time, so it might just be the air going round the systems from one of the zones....

John.G

I would leave the AAVs "permanently" open, there is also a long horizontal run from the flow/return headers to the cylimdercoil flow/return
Which will trap any released air, ideally a AAV should be installed as close to the cylinder as possible on the flow line.

CitizenFloor

I will leave the AAV's opened permanently eventually, when the problem is hopefully fixed. The only reason I am closing them now, is due to the fact that they are helping me troubleshoot. I can open them when I get home to check for trapped air. If I leave them open permanently now, the air will just escape as designed during the day, and I won't know if the problem still exists. But maybe there is a better way to troubleshoot, or maybe by keeping them closed I am causing some unintended consequences?

I am trying to understand your point.
Are the flow/return headers the valves? i.e. the place where the heat splits up/down/water? If so, there is only a run across the landing to the cylinder (at most 2.5 meters). The AVVs are on the flow line too.
And I had the hot water/cylinder zone off since the 3rd, so I assume its ruled out as the zone with air ingress.

John.G

Let the AAVs open for now and after few days or so you can then closeth as they justmightbegettingrid of entrained air still in the system. The fow and return headers are simply the hotter flow pipe and the cooler return pipes.

CitizenFloor

John.G wrote: »

Let the AAVs open for now and after few days or so you can then closeth as they justmightbegettingrid of entrained air still in the system. The fow and return headers are simply the hotter flow pipe and the cooler return pipes.

It would be great if that is the case! Ill do that and see how I get on.



FYI, I drew up what I believe is the way my system is set out. This is obviously just to the best of my knowledge....Does that layout make sense?

John.G

The return from each rad should independently go to the return header, you hahe shown it in a way that all the rads in each zone are plumbed in series which I doubt very much.
Edit the flow and return should be plumbed independently to the flow and return headers