PeterW

Loved his way of fixing the steel height issue ...!! Concrete saw and jigger pick !!!

Send me your address. When lockdown eases I will at my cost come down and measure the whole lot and do a full rad sizing and heat loss calculation and prove this lot is both undersized and isn’t balanced. It will also prove the point @joe90 has repeatedly made : The system is not designed or installed correctly and is undersized for the heat requirements of the building, and it is not fit for purpose.

Why..??! Just up the strength of the blocks to 140mm 10N and you can go to 4 storey with beam and block floors anyway.

So you will need 2 manifolds with all pumps and blenders. Veissman 200 19KW can modulate down at best to just shy of 2kW however that is at non condensing temperatures and still at a flow temperature of 50°C with a return of 30°C. The 50°C is too warm for a UFH supply and when you are at delta 7°C which is optimum for UFH flow and return you will be short cycling the boiler at its minimum setting when around 30-40% of the zones are satisfied. This will be exacerbated by having multiple manifolds potentially at different temperatures. Veissmann recommend (and size) the use of Low Loss Headers in this sort of situation - I’ve no idea on the heat load you require but a 60 litre LLH is probably the minimum I would specify and even then it would depend on the load / design of the remainder of the system. How many bathrooms / showers / occupants have you got in the house ..? 250 litres isn’t a big tank and you will struggle to recharge with a smaller system boiler. Go upward on the sizing of the boiler to keep the tank hot and the minimum power of the boiler burner will increase on the heating which will mean you need a larger buffer / LLH.

Only if the coffee costs you £4.50 for half a lukewarm cup...

That won’t work for a number of reasons. With UFH temperatures and a standard boiler - your boiler won’t get low enough. It “just about” works with an ASHP as they operate in the 35-45°C space but boilers don’t. You need a buffer tank of probably 100 litres to allow the boiler to not short cycle. Also, each zone will need its own actuator and controller, and you will also need pumps on each floor ideally. If you want different temperatures everywhere then I would look at a manifold per floor and ensure you get the pipe spacing properly calculated.

Yes - or use ICs as per @Temp but some people don’t like to see a row of IC lids so just put one so you have rodding access or a rodding eye at the top end.

Rest bends into angle tees run down the line is the way to do it. Don’t use ordinary bends at the bottom of stacks and don’t use 89° tees

Yep - materials not installed or fixed have no value, see this regularly with surveys.

Just brilliant tonight (apart from the usual “your budget is half what others spend from McCloud) And for what they spent it was superb finish - loved those walls and the way he sorted that roof pitch to get those roof lights in ..!

You are correct - it should say average flow temperature (now corrected..!) I was more engrossed in hunting through my standard variation tables ..!

Seriously, a number of us are trying to help and at every turn you say we are wrong. Unless you’ve got a floor to ceiling rad in the bathroom then you don’t have rads that are maxed out. Trust me, I’ve fitted some huge rads in my time and you’ve seen nothing ..! Standard boiler run temp is 65-72°C These will be “standard” rads but when you size them you change the flow temps. I’ll give you an example. Using BS EN 442, the industry standard for radiator sizing, a delta 50°C is assumed for calculation. This delta is the difference between the average flow temperature and the desired room temperature. Most plumbers / Heating engineers therefore use a flow temp of 70°C and a target room temperature of 20°C. My “room” example is a 3.5 x 3.5m living room with a standard ceiling of 2.4m. I’ve said it has two 9” solid external walls, and no insulation under the floor. I’ve added a single 1sqm window that is double glazed. The heat requirement of this room is 1540 W based on delta 50°C. To heat this room, I would specify a 1100 x 450 double convector compact radiator. If I now change the delta to delta 35°C, then the room loss is still the same but the rad now needs to be an 1800 x 450 double convector compact radiator. Do you see the difference ..?? The radiator for the lower flow temperature is 63% larger to accommodate the same heat requirement. I can - from your numbers and description - see that your bathroom should have something like an Opus 600 towel rail, which is 600 x 2000..!! If you’ve got anything smaller, it is undersized. It’s not the room, it’s the rads.

It’s a heat pump so won’t be as hot as the temperatures you see for a boiler Yep agree - and the rads need to be sized for the lower room / flow delta temperature

You don’t understand rad balancing. What you need to understand is that you need to reduce the flow - heat input - into certain rooms and increase it in others. That allows you to ensure that the rooms that need more heat get a better flow, and heat is “lost” to the room quicker increasing room temperature. For example, your workshop I would turn right down, whilst bathroom and bedroom sound like they need to be more open. Also, if the rad isn’t heating the room (such as the bathroom) then it’s too small. Rads have BTU or kW outputs, if the the rad is too small you will not get enough heat from it.

Thanks - always a worry when you see significant loads being added to a structure ..!

But the rooms aren’t heating up so how can you be “happy enough with the balance”..??! Balancing will sort some of these issues.

Have you spoken to an engineer about this ..?? You will be adding significant static load to the joists - potentially causing bending or cracking of the ceilings below if they are overloaded. Adding a 20-30mm pug mix will add up to 2 1/2 tonnes static load to the floor structure. You will also have to notch the joists to accommodate the pipes and this will further weaken the structure. Has all this been considered ..??

Contractors are maxed - that was a call to someone I know in the trade and they I know are working 6 days currently.

ouch !!! Pipe should be 45-65p inc VAT, depending on coil size. Just checked and 82sqm of pipe trays, pipe, manifold and pumps along with a few sundries was change of £975 when I ordered from Wunda last. Add in auto actuators and controls and it’s adding another £250 all told.

Ok they will get warmer on the circuit but to be honest you’ll need to switch it all on when the rads are cold and then start walking round and see which rad gets warm first just by feeling the joint where the pipe valve joins the rad. From this you start to balance the rads by turning all the lockshields off. Closest gets a half then open, next gets one turn and so on. You can also frig the balancing to give the more “needy” rooms more heat by opening them more than the ones needing less heat but it takes time and patience.

@LSBJust made a quick phone call and for corrugated sheet up to 60mm profile it was £37.50 plus VAT / sqm so it would be £1,800 inc. VAT for that lot. That’s a reputable contractor and it’s done properly.

Im not surprised as you have £850 worth of smart stats and sensors in there - did you ask for those ..?? And what are you stapling to if you are using battens and a Pug mix ..?? The staples go in to foam not timber.

I bet you this is the case !! Ask for his calculations and I think you’ll find your answer ...

Ok can you just do the list first ..? Let’s do this one step at a time. Room - Radiator - Size By radiator I want is it a double or a single panel please.

Yes a back extension - quicker easier and cheaper than the engineering you’re proposing as you will get the space without doing internal rework such as massive structural changes such as 9m steels. You could widen the two rear openings and go out into the garden with the extension without putting planning in place (assuming no conservation area and you still have permitted development rights) and it can be done quickly and easily. I don’t know many companies that would take that as drawn on with your budget as there are some huge unknowns, and if you are paying London prices then I don’t think your budget is realistic - sorry !