Browse Forums Heating, Cooling & Insulation Re: Hydronic heating what you should know!! 5Jul 22, 2012 11:41 am Thanks for that info loosh, The manifold is actually in the middle of the house under a staircase, I do have plans of the house that I sent to the installer explaining what zones that I required which I could send to you to checkout if you have the time. In regards to the A/C units, the 2 units downstairs which aren't being used at the moment I have isolated. I have a home energy monitor and after install I noticed that my minimum power draw had risen considerably so its pretty much back to normal now, thanks for the heads up. If I could get your email I could send you the docs if that is Ok?? Regards Dave Nisbet loosh Hi Dave, if you haven't sorted out the hydronic heating problems yet, I might have a few tips to help out. I work for a hydronic heating company (my father started it more than 30 years ago) and we instal a lot of in-slab systems....always with a piping diagrams and circuit labels of each of the 8 valves on the control manifold. They should have provided you with both, not to mention a full hand-over/ explanation of what was installed....and a return visit if you are still not satisfied. A general principle used to determine which circuit goes where, (this is much easier to describe with drawings and a reference point, but i'll try)- pipes should not cross over and they should not pass under walls (we always try to pass through doorways). So, the circuits should run in an order. For example, if we imagine your control manifold is located outside, midway along an external wall on the side of your house, the control valve on the left of the manifold should control the room/circuit/area closest to your left, (ie the room on the outside of the house directly to the left of the manifold), the next valve controls the room next along the outside wall to the left- the rest of the circuits will fan around to the house, in order, until reaching the room on the outside wall closest to the right of the manifold (connected to the valve furthest on the right of the manifold). To help work out the potential order of rooms (If you have floor plans), draw in your manifold location, then draw a line from the left of the manifold to the closest room on the left (passing only through doorways), circle the room, then draw a line back to the manifold. Next, draw a line from manifold to the next room (only passing through doorways, not crossing lines you've already drawn), do this for each of the 8 circuits and you should have a fair idea of how the system 'should' have been run. If your control manifold is in an area in the middle of your house, it may be more complicated, but if you can match one control valve to an area, it should help to work out the order. Of course I can't be sure that they have followed these principles, but that's how I would approach the situation if I had to solve it. Feel free to ask any further questions, I may be able to help out. We also deal with Mitsubishi air-conditioners, if they've been sized correctly, they'll be great. They're one of the top manufacturers of air-conditioners available and are one of the most energy efficient. A quick tip for saving energy, particularly if you have hydronic heating, is to turn your air cons off at the isolator or switch board- they use a surprising amount of power when on standby in winter (heating their refrigerants). Hope you have some success. Re: Hydronic heating what you should know!! 6Jul 22, 2012 5:21 pm Hi Dave sorry to hear about the grief you are suffering, poor service at the back end of spending sooo much money really sucks. We are in the middle of our 1st winter with hydronic heating and are still getting used to how to drive the system. Ours is complicated by the fact that we have installed it in and extended/renovated house. Like a lot of extensions these days we have kept a period front and added a modern box on the back. The old part of the house has panels and the new, on a slab, has underfloor. We recieved our 1st gas bill for the season last week....and I had a mini heart attack. Now pre renno we had a single gas vulcan wall furnace and a few electric panel heaters, the house was small and not very comfortable in winter. Now its huge with high..very high ceilings and can be heated throughout. I was however expecting the slab heating to be a little more efficient. Yes the thermal mass of the concrete really stabilizes the temperature.... but as night falls the 1 degree difference (we have it set at 21.5) triggers the boiler and it can work all evening to keep the room at that temp. We do have double glazing throughout, but that said ...there is still a LOT of glass in our main room. We are now contemplating curtains etc but will weigh up the cost/benefit etc. As for your circuit search, how deeply are the pipes set in your slab? Ours were laid in the top 100mm and are very easy to find underfoot. I understand your reluctance to turn a circuit off, but maybe try it on a weekday night, check it in the morning, then if you turn it back on all will be ok by the time you get home. When we were planning our system all those who quoted for us spoke of the bathrooms running warmer than the living areas and the bedrooms cooler again. In other words they spoke of being able to control temperatures in all the rooms. In practice this is a bit of a crock, unless you have a thermostat in every room. Yes I could have installed thermostatic taps on the panels, but that only works if the boiler is actually running and if the rest of the house is being kept at a higher temperature. In practice the bathrooms that are slab heated are a bit warmer …simply because they are smaller rooms. Despite all I have said I am very happy with the system, the only real change I would make is that I would have upgraded to a condensing boiler. Kicking myself now that I didn’t. Re: Hydronic heating what you should know!! 7Jul 22, 2012 5:29 pm loosh A quick tip for saving energy, particularly if you have hydronic heating, is to turn your air cons off at the isolator or switch board- they use a surprising amount of power when on standby in winter (heating their refrigerants). I also went with a Mitsubishi and have heard good things, thanks for this tip I have switched it off today. One question, is there any downside to switching it off in the winter? You mentioned that it uses power to heat the refrigerant, why does it do that and will it do the system any damage leaving it cold/off for the winter? Re: Hydronic heating what you should know!! 8Jul 22, 2012 6:40 pm Sceen7, The heater is used to keep the oil warm which basically boils the refrigerant out of the oil so when the compressor starts the oil viscosity wont be too lite to effect the mechanics of the compressor. When you are planning to use it (weather warming up) then I would turn the isolator back on and give it a day to warm the oil, if a day cant be done then at least as many hours as you can. You could start it with cold oil but it isn't recommended. P.S. I haven't received our 1st gas bill yet but I will keep you posted. I am upto around 700 cubic meters at the moment which shouldn't bite too bad!!. Regards Dave Nisbet.. sceen7 loosh A quick tip for saving energy, particularly if you have hydronic heating, is to turn your air cons off at the isolator or switch board- they use a surprising amount of power when on standby in winter (heating their refrigerants). I also went with a Mitsubishi and have heard good things, thanks for this tip I have switched it off today. One question, is there any downside to switching it off in the winter? You mentioned that it uses power to heat the refrigerant, why does it do that and will it do the system any damage leaving it cold/off for the winter? Re: Hydronic heating what you should know!! 9Jul 22, 2012 8:45 pm Dave Nisbet P.S. I haven't received our 1st gas bill yet but I will keep you posted. I am upto around 700 cubic meters at the moment which shouldn't bite too bad!!. Looking at my current bill I used 669 cubic meters which worked out to a bill of $425.00! or $6.79 a day. I was playing with the controllers almost every day to try and balance our needs and try different temps throughout the house. I also set the overnight temps quite high early on in the bedrooms, thats probably where i really went wrong. I am yet to try turning the slab heating off overnight to see how much heat it loses, might try that tonight to see what happens. At the moment I have it set at 20c from 11 to 6am. Our main room is bathed in sun all day in winter (tomorrows forecast looks ok) so I should be able to make up any deficit without using too much gas lol. Re: Hydronic heating what you should know!! 10Jul 25, 2012 2:26 am Current gas bill $142. Run hydronic radiator panels (x at 19-21 degs, turn off overnight. Boiler is a combi & services 2 bathrooms with hot water as well as the radiators. Windows are double-glazed (no curtains though) and are mostly uncovered cos I like my views! House never drops below 14 degs overnight. Outer east Melb. Think I'd die if my bill was $400 plus! Re: Hydronic heating what you should know!! 11Jul 25, 2012 6:34 pm Hey Supasquirrel what brand/type of boiler do you have? I have been keeping a close eye on our gas usage and so far we seem on track to be using way less, leaving the temp set so high at night was insane. Re: Hydronic heating what you should know!! 12Jul 26, 2012 1:11 am Have Baxi Luna. Check out Hydoheat supplies in Braeside. I agree heating a house overnight while your in bed under a doona is a waste of energy. Re: Hydronic heating what you should know!! 13Jul 26, 2012 6:41 pm yeah same boiler .... I've just been driving it like a leadfoot ....ex queenslander here Re: Hydronic heating what you should know!! 14Jul 26, 2012 8:24 pm Hi Dave, feel free to email anything that may help fix your problem- if you can email me through this website, it'd be good. the administrators told me off for putting contact details at the end of my first post....i don't know if i'm allowed to provide an external email address....? spot on with the air-con isolation (sorry for not explaining why, how, etc). curtains, regardless of double glazing, make a big difference- pop outside on a cold night and feel the outside glass to gauge how much heat is being lost. the baxi boiler range is great- the control panel provided with the boiler (often taken out and used as the inside thermostat) can be difficult to impossible for clients to use. we find that it's better to leave it in the boiler for servicing/boiler control, and instal another control (siemens, etc) inside as a more user friendly thermostat. ....running your hydronic heating systems at 20+ throughout the night is a luxury most can't afford! we advise our clients to try to work out how long it takes the room to heat to the desired temperature from a background/overnight temperature of about 14 degrees- for example 2 hrs, then program the boiler to come on 2 hours before they get up. you can usually get most this heat up time/energy back by having the thermostat programmed to turn off (for this example) an hour or so before you leave the house (residual heat in the slab will continue to heat the house). with hydronic radiators, it's more like 20 minutes before getting up and 10 minutes before leaving. Re: Hydronic heating what you should know!! 15Aug 06, 2012 11:10 am Disappointing to hear the problems. Hydronic heating is standard in Europe and North America. Although tubes in the slab is more Oz centric but a good idea than screed on top. "Australian Standard AS 2870 Residential slabs and footings — Construction, contains some requirements on heating cables and pipes within slab-on-ground construction. For hot water heating pipes embedded in the slab, to ensure that the required slab thickness is not reduced by the pipes, the slab thickness must be increased to at least 125 mm Figure 4 (a). Also, the reinforcement is to be increased by one level, from say SL72 to SL82 mesh. " Also insulation under the slab is highly recommended and edge insulation required. The BCA specifies that vertical edges of slabs on ground are required to be insulated when in-slab heating or cooling in installed within the slab. See 3.12.1.5 Floors in BCA 2010 Volume Two. Also see this fact sheet: 4.8 Insulation Installation You should get some ideas of certain zones by turning one off over night. There would have had to have been some design work, to work out zone lengths, before turning up to job site to lay pipes. Good Luck Pulpo Re: Hydronic heating what you should know!! 16Aug 06, 2012 7:52 pm Again I slap myself in the forehead for not getting on these forums years ago. It’s often the questions you don’t know to ask that trip you up in the end. On the whole I am happy with the system and the installation but some of the advice in the last two posts would have been nice to know at the outset. Pulpo when you talk about side slab insulation what do you mean? Our heating was laid in a 100mm overlay, similar to the screeding done in Europe as you mentioned. When the frame was constructed on the slab a double thick bottom plate/timbers was used to box in the overlay. I’m hoping this provides some insulation along the exterior walls. Under slab insulation was mentioned in the quote phase but all four companies I spoke to warned it was very expensive, and not that necessary in my case. The structural slab was nearly 300mm thick (p class soil) so there is almost 400mm beneath our feet. We have experimented some more with our slab heating leaving it completely off overnight to see how much heat it loses. Even on the coldest nights the thermostat has only dropped to 18. Our main living space was designed to get as much winter sun as possible…and that’s working a treat. So generally the boiler only works on the slab in the evenings. Agreed curtains would help as we have lots of glass, I just have to do my sums to check if its cost effective. Quotes for the room were frightening, north of 4k for heavy curtains, and we don’t really want them lol. Re: Hydronic heating what you should know!! 17Aug 07, 2012 8:25 pm Latest update, I have spoken with the installers and didn't really have a warm fuzzy feeling as they were more peeded of about me posting on this website. (I sent them an email regarding my problems and also sent a link to this forum) Anyway I did discuss with them which circuits are supplying what areas of the house, from what they could tell me sounded logical with the closest circuit on the header/manifold going to the closest areas of the house. I rewired the outputs from the control system to do this. Next night I get home and the living area is 22.5°C and the front of the house is freezing. I put 1 and 1 together and realise that the whole system is piped in the opposite of what you would think. I then rewired again to suit the opposite of what I was told and now are getting comfortable temperatures throughout the house. The circuits that are closest to the entrance of the house are actually feeding the living area up the other end of the house. I also had an interesting conversation with them in regards to how to run the system. They basically said to run the boiler/heater continuously. They said that I should have a minimum of 3 out of 8 valves open. They also said to set the temperature setpoints back at night. Well if all zones are at temperature and the setpoint is setback by 2°C then the valves will shut, so if all of the valves are shut then there is no option but to turn the heater off as all it is going to do is recirculate water around in a loop. Anyway I have (I think) found a happy medium where I have the system running from 3:00am to 9:00am then back on from 3:00pm to 9:00pm and with in the software (glad I have a programable system) of the control system will not have the heater running if less than 3 circuits are open, I may get to the stage where I leave the system on 24/7 and rely on the controls turning off the heater if there are not enough valves/circuits open. I am trying to run this as efficiently as possible. We did get our 1st gas bill which was usage around 700 cubic meters or 26600 Megajoules (approximately) whic cost around $400.00. We are using the gas dryer every weekend which doesn't seem to use a lot of energy compared to an electric one. In regards to slab insulation, as far as I know there was no insulation installed and the heating coils are arouns 25 to 30 mm below the finished slab height which is 150mm. I have had a quote for materials only to insulate the edges of the slab which was around $300 which from what I have read saves around 5 to 10% on energy cost's. (I was never informed about this!!!) So the system will continue to run and I will continue to update post's as the information is learned. At present, I do see some light at the end of the tunnel but I am glad I have an interactive control system which is telling me everything that is going on. If it was just wall thermostats the only thing that would be telling me that things are not right would be temperatures all over the place. P.S. I am now involved in a commercial building in Melbourne CBD that has 6 circuits of hydronic heating in the ground floor with a 3 storey atrium above. We will be controlling it and I am very interested as to how it is going to work!!! Re: Hydronic heating what you should know!! 18Aug 08, 2012 11:15 pm Regarding edge insulation is highly recommended http://www.heat.net.au/action-advice-pa ... on_web.pdf Sceen7 You have 300mm concrete slab and another 100mm screed on top? Or was it 50mm Screed with 50mm insulation underneath (the only way I would do it if doing screed). 300mm slab sounds excessive, beams yes but the whole slab, I would get another another engineer. Yes double studs would be ok for edge. Curtains are a must, I'm trying to develop an insulating curtain. I try to make the Zones equal distance in pipe; there is no way I would rock up to start laying pipe unless just labouring, must plan. Extruded polystyrene I think 30mm is R1 which is around $20 m2, this should be used for edge slab. Good luck Pulpo Re: Hydronic heating what you should know!! 19Aug 14, 2012 10:09 am Pulpo Regarding edge insulation is highly recommended http://www.heat.net.au/action-advice-pa ... on_web.pdf Extruded polystyrene I think 30mm is R1 which is around $20 m2, this should be used for edge slab. Pulpo That's what we're planning on doing ie. use extruded polystyrene for edge insulation (and also for the slab). However, we've got problems trying to work out how to seal / keep the whole thing air tight. Our renovation would be an alteration and addition type, where original front of house is kept but reconfigured as predominantly sleeping areas and an open plan extension added to the back. Because we're located at the foothills, the back of the house is on a slight incline so the back slab of the house will be raised to keep the floor work inside the house all at the same level. The problem our architect is trying to work out is how to keep the edge insulation contained given that it will be 'exposed' above ground as opposed to it sitting inside a trench sandwiched between concrete and ground. There's also the problem of the insulation jutting out from the external wall below. Does that make sense? Thus, will look awkward aesthetically plus will assume the insulation will need some sort of cladding to cover it as well meaning will extend out even further in comparison to the external wall. Re: hydronic heating 20Aug 14, 2012 8:41 pm Sounds like you know what your talking about!!!!!!! thanks for hyjacking the post with the crap that you write...... I posted this to try and help out people that are looking at putting in hydronic slab heating!!! ankur_ rawat Hydronic heating is a adjustment of heating the home through the use of hot baptize as against to balmy air. 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