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Underfloor Heating - A couple of issues

Discussion in 'Plumbing and Central Heating' started by abbadon, 30 Nov 2017.

  1. abbadon

    abbadon

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    Hello,

    I am hoping for some assistance troubleshooting my UFH system.

    Background:

    House is about 10yrs old, we are the second owners.

    Boiler is a large combination boiler, housed in the garage.

    Heating is UFH throughout property, on both floors.

    There are two manifolds, one on ground floor, one on first floor.

    Downstairs, the manifold feeds circuits as follows:

    1. Living room one end
    2. Living room other end and hallway
    3. Kitchen
    4.2nd reception room
    5. Orangery - this is turned down, as its not used much in winter and would cost a fortune to heat it to normal room temperature.

    The downstairs WC is where the pipes all run under, the manifold being hidden in the wall between WC and kitchen . So it doesn't have a circuit of its own, a couple of loops from kitchen circuit run on one side before they go out through the hall to kitchen.


    The living room has the controller in it, and a room stat. Controller is set to 30C so when the program is set to be on, the room temp doesn't shut down the whole system.

    Room stat set to 21C.
    This stat runs actuators for the two living room circuits.



    The kitchen, and reception 2 have room stats respectively.


    The orangery is manual valve no stat at the moment, hence the throttling of the manual valve to limit flow. This seems to work fine, as its floor isn't warm like the house, but its certainly not cold tiles as it would be with no heating in the floor.

    So to the issues:

    1. Since we have lived there, I have found one side of the kitchen floor, and the utility (both are one circuit from the manifold) is cooler, but this winter, even though its not that cold yet, the utility is down right chilly.

    When we first moved in, I spoke to the manufacturer and they helped me tweak the settings, as we had some other issues (upstairs the water was set too cool and floors weren't heating rooms, and pumps were all set on 1 in manifolds...). They advicsed setting two or three on the manifold pumps, and upstairs its set to three. Downstairs, I have tried 2 and 3 and it has not remedied the situation. Setting 3 makes something in our walls resonate, unfortunately they fitted the manifold to the studding, not to a brick or block support :(

    2. I noted yesterday, that despite the room stats all having turned off, and rooms all being at temperature, the pump was still running. Since I had left the pump on setting 3 downstairs I was able to hear it. I double checked and all stats required turning up to get a click, so they were all off at idle. This should mean downstairs system should not circulate as I understand.

    I set the controller to off, then back to auto, and the pump did not then come back on, unless I bumped any of the thermostats upward, as expected.


    So, my main question is ref the kitchen colder floor on one side, in particular on the further end of the loop on that side, and the utility (both one circuit.)

    Secondary question ref the pump behaviour.

    My manifold is of this type:

    [​IMG]

    System layout downstairs - orangery not shown, these were plans left from the prev. owners.
    As far as I know its correct. The plans from 1st floor didn't quite match the final house - only because they moved a door probably after the initial quoting was done for heating, but walls etc.. all seem to be in the right place.
    upload_2017-11-30_14-2-11.png
     
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  3. cully

    cully

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    Hello Abbadon,
    Just some thoughts whilst reading your thread, as follows:
    Is the pump seeing demand because the controller is "on" even though all stats are "off" This does not explain why the pump didn't start when you turned the controller off then back to auto but the pump is getting a supply from somewhere, it's a job for a multi meter.
    What sort of wiring centre is being used?
    I have just changed to heatmiser programmable stats using their wiring centre.
    With regards to cool floors in the kitchen have you control over the flow rates of all circuits? do the flow valves need adjusting (as in balancing rads) to get more flow to the cooler circuits?
    Introduce some soft rubber between the manifold and stud wall to negate the resonance
    As I said just some thoughts whilst I sort out my UFH problem
    Cully
     
  4. abbadon

    abbadon

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    Hi,

    I have not noticed the pump running when I didn't expect it to before. I noticed in this instance because I was a bit warm and wondered why the pump could be heard when the rooms were clearly all at temperature. So I checked and confirmed all stats were off. Maybe hysteresis at work.

    Ref wiring centre, I would have to go and delve back in to the cupboard, I might have a photograph from when I changed an actuator a while back, ill dig through my phone photographs.

    The manifold has small turn screws on the outlets, you cant really make them out on the photograph above, but the lower connections, on the more brassy coloured bit, there is a slotted bit to turn.

    No flow meters however.

    Now when I spoke to invisible heat, they said all outlets should be straight down, no balancing required, and that's how it was set when I first looked at it.

    I can see why you ask, as obviously , in general, system should be balanced, be that radiators or under floor circuits.

    From the diagram, you can see that kitchen is 4m longer than two of the circuits, and those two are 6 m longer than the shortest, but all circuits are within 10m range of lengths.

    Would we expect this to require much flow adjustment, and could this be the cause?


    Ref the vibration, as it stands, the manifold is mounted on some rubber bits between its mounting ears and the chipboard that's then bolted to the studwork. But its obviously not doing the job, or the vibration is actually transmitting up to another part of the structure which is resonating. The rubber isn't what id descroibe as that soft however, so maybe something softer would help - but i'm not sure how I would fit it. I think the back of the manifold might press against the flat wood - I expect if that portion was in free air it would be less of an issue. Any other options?
     
  5. abbadon

    abbadon

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    Anyone have any pearls of wisdom or experience of the invisible heat systems and balancing?
    Andy
     
  6. cully

    cully

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    Hello Andy, me again.
    What is the flow and return water temp at the ground floor manifold?
    What happens when the dining and lounge stats are at room temp and off and the first floor heating off do you get more heat into the kitchen floor?
    The circuit actuators move a spindle for "off / on" has the kitchen circuit spindle free movement (not sticking as you sometimes get with TRVs)
    Removing actuator and operating spindle will answer that.
    Paul
     
  7. abbadon

    abbadon

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    Paul, thanks for replying again :)

    I did have a shufty the other day, I have been poking my head in there every now and again, I really need to do it when the heating has just turned on from cold?

    I think I saw that flow was 50, and return was about 30, but I could be remembering wrong - I always usually take a photo of this sort of thing, I must not have had my phone to hand.

    Ill try and have a look a few times tonight/tomorrow.

    I will have to try bumping the kitchen upwards and leave the others alone, so that hopefully it stays on longer , so I can see if it makes any difference, this might not be easy with all the kids about etc.. With a radiator based system this sort of investigation is usually easier as it responds so much quicker, with underfloor it might be a fair time before I can discern any change - can you recommend any methods to help ? Would I be able to discern any change in temp on the skin of the plastic pipe returning from the kitchen floor?

    The actuator is on top of the valve, and the actuator, when it warms I think allows the pin to rise, opening the valve, so if I take the actuator off, I should get the circuit fully open.

    I replaced one of the actuators last year for living room, as the body had fatigued, so it was being pushed off by the pin, so half the living room was always on, but that's fixed now.

    Andy
     
  8. cully

    cully

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    Andy, your flow temp's seems fine, mine runs at 50 / 55** and the return is dependent on the heat in the screed warming up so again my return when all rooms are up to temp is around 40* (designed 10* diff between flow and return)
    It will be difficult to establish individual circuit temps when all are working it would need the other circuits closed to establish what is happening with the kitchen / utility.
    If you take the actuator off it is as you state, the valve is open and the only restriction is the flow valve setting.
    Paul
     
  9. abbadon

    abbadon

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    So, I realised the mixing stat was actually set up above 50, and was reaching about 60 in practice, so I dropped that down, its now at the more advisable 45-50 or so, and this morning I remembered to take a snap in the cavity when I left house at 5.45ish, so heating been on for about 15 mins.

    so the outlet was at approx. 52C and the return was at 45C. Pump is set to setting 3 (jet engine setting)

    now one weird thing, only one of my actuators has a visual indicator when its open, a small lump on top that rises, it wasn't up. but the stat in that room was calling for heat, as I could feel heat in the head for the other end of the room, and this one also felt warm where the capsule is. so ill have to look at that.


    Also, the pump was again running on last night, even once all downstairs stats were not calling for heat, the pump ran on until I turned the controller off and on again. It then didn't come back on until required this morning.

    Is this likely to be an issue with the wall controller or the board in the cupboard which everything is wired to, or is there some recirculate logic in play where its supposed to keep circulating the water?
     
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  11. cully

    cully

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    Andy,
    As far as the design temp of the system is concerned the real problem, I believe, is ensuring that the temp. at the screed does not damage floor covering (some tile and all hard wood floor suppliers specify a limit around 28*) so running the system at 50* shouldn't be an issue.
    (The engineer who commissioned my system in 2001 set it at 55* with the design stating 45*)
    If you have no flow meters than how do you know you have "adequate" flow to the circuits? (picking up on your situation with a possible defective actuator) I can see velocity in my circuits I know that the actuators are fully off when heat is demanded.
    Take the kitchen actuator off for a few hours to see (feel) the effect in the room.
    When the stat calls for heat the zone valve is operated which opens the actuator, starts the manifold pump and fires the boiler, conversely when demand is satisfied the stat trips, closes the zone valve which takes power off the manifold pump and boiler. The pump doesn't circulate water after the zone valve closes.(there is no water to circulate)
    I am not an electrician but wonder whether there is one or two loose wires in the wiring centre
    I would isolate the heating and ensure that all wires in the wiring centre were secure in their terminals.
    See how you go.
     
  12. abbadon

    abbadon

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    You give sound logical advice, and your thoughts are along the same line as my own, I was hoping for validation of them, so thankyou.

    I agree, the pump running when all stats seem to be not demanding is not right. I need to check if the boiler is also firing, as that would be more annoying! Its in garage so I didn't do so the other eve.

    One challenge is whenever I am home in the week, the kitchen is always warm, due to the floor being toasty on one side, and the oven often on and or cooker, so often its up at 23 or even 25 when I get home due to cooking, and with the floor up to temp from the day, its very hard to discern any rise or fall even well in to the evening :(

    The utility is certainly cold however. I guess one though in my mind is that the water is cooling too much on the first sode of kitchen and its too cold by the time it reaches the utility, but that would seem strange.

    I think I will close the orangery circuit off completely temporarily, to ensure its not robbing too much flow.

    Can flow meters be retrofitted to my manifold do you think? Outlets are on the bottom, and actuators are the return correct?

    See wiring centre image:

    4 white wires are actuators, two go to one block as they are driven from one stat in living room.

    black cable is pump.

    three grey cables furthest right are stats as far as I can tell.

    Nothing seems loose or no signs of blown components, at least on this side....

    Any thoughts - I know a photo isn't much to go on!

    Andy



    20171204_202700.jpg
     
  13. cully

    cully

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    Hello Andy,

    I think you might have given part of the answer to your utility heat problem as above.
    Could it be a combination of factors, poor / reduced flow and the above quote. ((remove the actuator (which is on the return flow) and set the kitchen stat high to establish what heat you can get into the kitchen / utility.))
    My kitchen floor is usually cold because of the heat from other rooms, cooking, lights, humans etc gives me the 22* the stat is set at.
    I have a different circuit for the utility so it isn't compromised as yours is but if it was the same circuit then the utility would never come on.
    It does not explain the difference between this and last year unless a lifestyle change gives some explanation.

    When the UFH zone valve gets power from the stat it opens the mechanical valve to allow water into the circuits, when it is fully open it makes contact with a "end switch" that powers the UFH pump and fires the boiler (if the boiler is not already on for other heating demands)
    All the above happens within the zone valve.
    Normally the problem with the end switch would be associated with the syncron motor not powering the lever to that switch but if the switch was faulty?? (still difficult to follow as the power for the zone valve comes from the stat which at this point is off)
    With all other stats off fire up the UFH to establish whether the pump and boiler remain on occasionally after the stat is turned off.
    You can change the power unit of the zone valve without effecting the water side.
    It is difficult to work through the wiring centre picture. I cannot see your zone valve wires only see four actuators, pump cable and "seven "three core & earth?"
     
  14. cully

    cully

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    Andy,
    Re above dismantling zone valves apparently some do and some don't dismantle without getting wet.
    Paul
     
  15. abbadon

    abbadon

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    Hmmm, I'm not sure we have any zone valves, this woukd be a 2port valve yes? Where would you expect it to be located, near manifold on the boiler to manifold feed?

    I did read a thread somewhere where people had a system wired up that was suffering pump running on, and it was because a signal was reaching pump on one zone, from the other zone. Next time it h as pens I'm going to check if all upstairs stats are off, and if not, whether turning all off stops the downstairs pump?

    I did recieve a call from invisibleheating on Sunday (good customer service!) after I left them an answerphone Friday afternoon.

    He did suggest the location of kitchen stat, near to door to hall, and the warmer side of kitchen, might be contributing to the issue. I may get a wireless stat and try moving the sender to utility, set at 18 ish, and see if that helps pull up the room temp. But I'll try head off of actuator first.

    Andy
     
  16. cully

    cully

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    Andy
    You have two manifolds, I presume two separate systems
    UFH ground floor with a controller (programmer) in the living room.
    UFH first floor that will also have a similar programmer and stats controlling the first floor circuit?
    Both manifolds have pumps attached (as your photo above) so when either floor programmer and one or more room stats demand heat they open their respective actuators.
    When the manifold actuator(s) open they open that systems two port zone valve which starts the manifold pump and fires the boiler.
    If each system didn't have a zone valve then I don't know what stops the pump when all the manifold circuits are closed
    The zone valves could be in the garage with the boiler (my zone valve is with the manifold but my son has two 12 port manifolds supplying his ground floor circuits and both zone valves are with the boiler.
    The position of the room stat does play a part but you could increase the temp where it is.
    It doesn't explain one part of a circuit cool and the other warm, also the difference this year to last unless it's because of the outside temp. we have at the moment.
    (Great playing around with the heating with minus temperatures outside)
    Paul


















    You will have two zone valves
     
  17. abbadon

    abbadon

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    Paul, that's the thing, what if it doesn't have them, when a stat demands heat, it would open actuator and call for boiler and pump. So without a zone valve would you get boiler feed to both manifolds? but only one would have its own pump circulating? Just thinking aloud here.

    I did a bit more fiddling tonight, and discovered something odd. The pump was running on lower manifold, but all downstairs stats were off. I went up stairs and checked all 4 stats up there... Two were off, two were on, and when I knocked both those off, the downstairs pump stopped. But turning either of those stats back on didn't restart down stairs pump. But more oddly, turning one of them back on didn't seem to start the upstairs pump?? Turning a downstairs stat up kicked the downstairs pump back to life, and then only fiddling upstairs would stop it as before.

    Really odd, but this seems to maybe support some odd wiring and maybe lack of zones which should perform the and/or logic choice for the system?

    Andy
     
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