RHayes

From what you've drawn here looks like it will work with the boiler providing heat to the buffer tank controlled by the tank stat, in order to maintain a constant source of heat in the buffer, regarless of demand from the UFH. Then the UFH will run standalone with pump, zone valve and actuators. Seems okay. I know I have joined this thread a little late, but I'd like to ask why the buffer tank with a boiler? In my view the buffer tank connected to a boiler is an extra source of heat loss from the system and unncessary load on the boiler as the buffer tank will cool down, causing the boiler to come on even when there is no demand from the underfloor heating. Most underfloor heating wiring centres have a boiler enable switch so that the boiler comes on only when the underfloor heating needs it to and then the blender valves control the amount of heat fed to the floor. This way the boiler only runs when needed and only heats the water needed instead of the whole of the buffer. As opposed to an a GSHP in the original diagram where heat pumps are, in short, much more sensative than boilers and need the larger body of water and a 'buffer' potentiailly between supply and demand. Welcome anyones thoughts to advise if I am missing something.

Sounds good MortarThePoint What type of screed has been used? Is is a dry sand and cement type or more of a flowing/liquid screed? If its a flowing screed then in most cases the latence will need to be removed any time from about a week/10 days after and some screeders offer this as part of the job. This will take out any of these small bumps you have.

Valid point. Apologies I overlooked the fact that the barier is the aluminium. Apologies for the misinformation.

Yes, that is likely to have prevented it. I know we wrap our pipe in black wrap to prevent UV exposure and are able to store this outside for this reason.

There is a good chance that the UV exposure will have degraded the oxygen barrier in the pipe.

Yes, the floor finish is key. Timber will shrink or contract as it is heated due to the water content reducing. Unless you control the rate and level of change you are likely to get gaps apearing between the floor boards. For any timber finish floor surface it is important to control the floor surface temperautre to prevent over heating and the gaps apearing. The actual science of it is to make the tempertaure change of the timber floor as slow as possible and most floor manufacturers specify a floor limit of 27 or 28 degrees. If it isn't the finish floor surface what would you be putting over the top? Regards R

This depends on how much floor build up you have or floor to ceiling height you have spare. Also what floor is this on and what floor surface will you be finishing with? Need a bit more detail on this. Regards R

If it's not too late I'd go for your option 2, both loops to outside, as that is where the heat is lost. Better still is to run the pipework parallel to the windows and starting with flows to outside or at least flow to the window first, as this is likely to be the highest heat loss area of the room. Hope my recomendations is not too late for you to install in this way.

Hello Lawrence If the AV system is a permanent fixture then I'd stop the pipework short and not heat under it. From an underfloor heating point of view all you do is save a little pipe, however you may need to tighten the spacing a little bit to put the amount of pipe needed in the room to sufficiently heat it, your designs should confirm this for you. If it isn't a permanent fixture or if it comes to you moving house, then not piping under it will leave a 50cm cold area of the floor. It will be waying up the benifits of not heating your AV system (I can't imagin this would be too bad for the AV system) vs having a cold area of floor if you decide to move the AV system or change anything down the line. Re the feet, if it is 10mm or less this will heat the AV cabinet a bit and will also act like a rug over the floor in terms of heat output in the area covered by the cabinet. If it is more than 10mm then this becomes significantly reduced the higher it is. Trust this Helps R.

Agree with Simon, when designing our systems we always seek to put the manifold in a central location for that reason. If its not too late and if supply pipework runs supported it I'd recomend putting the manifold in the utility and send some pipes under walls, that way you minimise any pipie bunching and reduce transit pipework lengths. However coming back to the design, we have done many like that over our 18 years and don't typically have a problem. Insulating the flow pipework is a good idea where they are going through a narrow hallway as you have here.

Hello Joeirish Thanks for the photo. I have come across these manifold valves leaking before but not to that frequency or repetativeness that you seem to be having. Have you concidered upgrating or renewing the manifold? Are there any valves that you have had to replace more than once out of the 8? If not then it may be a batch problem from the original manifold batch. Just a thought. If you'd like to change the manifold would be happy to recomend.