Each room in a property will have a different requirement for heat input. We need to establish the correct pipe spacings for each room based on the same flow temperature. This may require 100 ml spacings in one room and 300 ml spacings in another
Hi Andrew, I have this design guide and have a question, not sure if its worth a video but how is circuit flow rate calculated? The design guides calculation doesn't seem accurate?
What would you do if there will be system boiler with cylinder and hestmiser controllers in place to control very large ufh and radiators? There is not much really you can do there. Everything would need to run on 70 degrees right?
You can fit WC on any underfloor system to get better comfort. Efficiency from the boiler will be improved with WC also even if set for the radiator circuit.
Andrew we have new builds that are 200m2 floor area with a heat loss of 3.8kw at dt24 and given a 35 degree flow temp we have rooms ranging from 250 to 150mm centres would you be looking to push the flow temp lower than this? This particular house is getting a heat pump
@@foodforhumans9152 I always just think you should design for the lowest temperature. But the difficulty is the various heat outputs required for different rooms. It's a bit of a designer's game you look for the room with the highest heat loss per square meter and allocate 100ml spacings for that room. You then got to try and select the correct spacing for the same floor temperature to give the required heat output from the floor area available for each of the other rooms . It might become the case during this process that 100ml spacings 150 millimeters as a minimum spacing
@@andrewmillwardwatford9410 that is exactly what I have done with the project I am working on at the moment. The one complicating factor is that there are two rooms with rads and I am going to run everything using one pump open loop at dt5 essentially treating the two rads as two underfloor loops so I am designing everything to 35 flow and the rads are not too stupidly big. Do you see any issue with this? The total heat loss is only 3.8kw
@@foodforhumans9152 I always find it strange the radiators and underfloor should work on the same weather compensation ratio if they are designed for the same flow temperature on a design day. However everything I know and everything I can read suggests that they will do. So I have not tried this myself yet and I've not seen a system where the radiators and the underfloor do actually run on the same whether compensation ratio. There are many Engineers that claim to Design Systems this way for heat pumps and that they get the correct results. However I've spoken to a number of Engineers who have tried to do this and found that the radiator circuits are not providing the heat output required. So in my opinion it would seem to be a good idea to be cautious and plummet in such a way that you could add the necessary mixes later if it finds to not be suitable
1.Whats the maximum a floor temperature should be before it becomes uncomfortable to walk on (I thought 27c was max) and are them MWT shown for when it's -3C outdoors? For a 20c indoor design temperature, the 40 MWT example shows at 100 centres that the floor will be 25.8C. 2. I'm presuming to obtain the tight radius using 100mm centres, it needs to be laid in the snail pattern not serpentine, is this possible for narrow rooms like a hallway or utility room?
Like the old saying goes........"Its better to be looking at it, than for it".
Hi,Andrew for the heat pump most likely it should be 100 centre ?
Thank you
Each room in a property will have a different requirement for heat input. We need to establish the correct pipe spacings for each room based on the same flow temperature. This may require 100 ml spacings in one room and 300 ml spacings in another
Thank you for everything you do, top man I hope I will meet you again
👍🏾
Hi Andrew, I have this design guide and have a question, not sure if its worth a video but how is circuit flow rate calculated? The design guides calculation doesn't seem accurate?
Mass flow rate. Dt and power required. Dt7 is normal for ufh.
What would you do if there will be system boiler with cylinder and hestmiser controllers in place to control very large ufh and radiators? There is not much really you can do there. Everything would need to run on 70 degrees right?
You can fit WC on any underfloor system to get better comfort. Efficiency from the boiler will be improved with WC also even if set for the radiator circuit.
Andrew we have new builds that are 200m2 floor area with a heat loss of 3.8kw at dt24 and given a 35 degree flow temp we have rooms ranging from 250 to 150mm centres would you be looking to push the flow temp lower than this? This particular house is getting a heat pump
@@foodforhumans9152 always as low as possible
@@andrewmillwardwatford9410 so the room with the lowest heat loss gets 100mm and the others are based on the flow temp as benchmark I guess?
@@foodforhumans9152 I always just think you should design for the lowest temperature. But the difficulty is the various heat outputs required for different rooms. It's a bit of a designer's game you look for the room with the highest heat loss per square meter and allocate 100ml spacings for that room. You then got to try and select the correct spacing for the same floor temperature to give the required heat output from the floor area available for each of the other rooms . It might become the case during this process that 100ml spacings 150 millimeters as a minimum spacing
@@andrewmillwardwatford9410 that is exactly what I have done with the project I am working on at the moment. The one complicating factor is that there are two rooms with rads and I am going to run everything using one pump open loop at dt5 essentially treating the two rads as two underfloor loops so I am designing everything to 35 flow and the rads are not too stupidly big. Do you see any issue with this? The total heat loss is only 3.8kw
@@foodforhumans9152 I always find it strange the radiators and underfloor should work on the same weather compensation ratio if they are designed for the same flow temperature on a design day. However everything I know and everything I can read suggests that they will do. So I have not tried this myself yet and I've not seen a system where the radiators and the underfloor do actually run on the same whether compensation ratio. There are many Engineers that claim to Design Systems this way for heat pumps and that they get the correct results. However I've spoken to a number of Engineers who have tried to do this and found that the radiator circuits are not providing the heat output required. So in my opinion it would seem to be a good idea to be cautious and plummet in such a way that you could add the necessary mixes later if it finds to not be suitable
1.Whats the maximum a floor temperature should be before it becomes uncomfortable to walk on (I thought 27c was max) and are them MWT shown for when it's -3C outdoors? For a 20c indoor design temperature, the 40 MWT example shows at 100 centres that the floor will be 25.8C.
2. I'm presuming to obtain the tight radius using 100mm centres, it needs to be laid in the snail pattern not serpentine, is this possible for narrow rooms like a hallway or utility room?
Floor temperature and mwt are not the same. I think 27 or 29 from memory if in traffic area.
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