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Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
Is it an Excell 96E?
Was the heating range rated to allow for the difference between rad size and boiler output. If you have a boiler chucking out 28kW but only 17kW of rads the return temperature will rise rapidly, so the boiler cuts out. This leads to cycling which could account for the three hour heat-up times.
Range rating instructions are in the installation manual.
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fuzzy
No, i meant correctly sized, if i meant hugely over sized i would have said so.
If the heat requirement is 7k including 10% for initial heat up, if not add this on, still rads should equal 7.7kw and therefore be correctly sized. Your outside temp is a bit extreem, where abouts do you live, we normally use -1 or maybe -3/4 for the highlands of scotland at max. Inside temp is normally 21 design temp
The reason it is taking so long is because you have used the wrong size radiators, there is too much water in the system, or should i say, more than you needed. so you have proved my point for me, thanks.
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fuzzy
many people think my rads are undersized, they look so small comapered to other houses. they get hot real quick and then gently raise the temp of the room, i use it with a programmable room stat and we never know its on, the heat in each room is equal and comfortable. people want massive rads to feel it bouncing like you would a fire, poor design. correctly size rads lead to equal comfort temps which dont over and undershoot, leading to poor efficiency and rarely being in your comfort zone
Buildings such as churches would benefit from a MVHR system to bring the heat back down to earth
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tamz
Or maybe just the old bit 2 or 3" run through the pews off a 1 pipe. Because it is old don't mean it doesn't work in the "modern" world!
Overhead radiants work too if you can fit them discreet.
Overhead radiants work too if you can fit them discreet.
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fuzzy
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fuzzy
skirting board heaters etc, all work pretty well
rads are great domestically, and large column rads look good and work well in big open spaces
rads are great domestically, and large column rads look good and work well in big open spaces
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Big Graham
Fuzzy, not long moved into new house, so its an existing system which i will rectify.I`m in Scotland, we had a full month this year when it did`nt go above zero.We had long periods of time where we were below minus 10.The climate does seem to be changing.2 years in a row we have had freezing conditions for a month at a time.Time to amend your calcs guys.As for the churches, I have been looking at the skirting stuff, a friend mentioned another product which uses far radiant heat, apparently its fairly cold to touch but produces this kind of heat.Need to research that 1 !!!
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Big Graham
Radiators cant heat a large volume space efficiently, You can design them any which you like but this is an impossible task.Remember the word being efficient !!!.The problem with large fans at ceiling height creates horrendous levels of convection i.e. the old lady sitting at the back of the church lets rip (breaks wind) 10 seconds later the vicar is choking, smelling her cabbage, potatoes and ham from the night before.I`ve came to the conclusion the radiant heat is best.The product to use is a difficult choice.
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fuzzy
i dont understand how your example affects efficiency?
If you are refering to comfort conditions of best type of heat you may have an argument but i dont get why you say efficient?
i would also argue rads are good for large open spaces, but it depends on the type of open space. often large open areas such as reception areas use convectors fan assisted, this is to improve heat up time as rads are slow but effective way of heating the space. with doors opening frequently they loose the heat fast so need a fast heat up time to componsate
most churches have rads, and 1 pipe systems, which is only the same as a rad in a tube!
If you are refering to comfort conditions of best type of heat you may have an argument but i dont get why you say efficient?
i would also argue rads are good for large open spaces, but it depends on the type of open space. often large open areas such as reception areas use convectors fan assisted, this is to improve heat up time as rads are slow but effective way of heating the space. with doors opening frequently they loose the heat fast so need a fast heat up time to componsate
most churches have rads, and 1 pipe systems, which is only the same as a rad in a tube!
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Big Graham
Ok, Lets talk efficiency.You install a condensing boiler thats lets say 92% efficient.8% lost from fuel going in and transfer loss within the boiler mechanism.Get back to my large church, efficient, comfort.If the church at ground level is 15 C, then thats not comfortable.But ur rads 15m up have produced 22 to 23 degrees below the roof !!!!!!!!!!! Rads have kept the pigeons warm but the poor church goers are freezing.Defending a technology thats ur bread and butter is all fine and well, but rads are not efficient.The church will need a minimum of 220kw thats keeping the pigeons warm.Thats potentially on a sunday for 3 hours 660kwh and the people will probably still be cold.Lets now install a biomass boiler with a dual system of underfloor and a suggestion of skirting heating.We now need around 180 kw maybe less.3 hours and we have a total of 540kwh and radiated heat is better than convection rads.And there may be a payment from the RHI.660 ? or 540 ?.Your last post you said rads are slow but effective, which is it slow? or effective ?.
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Big Graham
Convected heat from rads can travel around 0.3 to 0.7 meters per second, by the time it rises in high rooms, it will lose a lot of its energy .Perhaps through a long period of time the heat will build up from the top working its way down to floor level, after all if a roof has a U-Value of 1.0, its losing heat constantly by then how many kW have been emitted to create that heat build.Thats not to mention that someone doesnt keep opening and closing the doors and letting the heat out.Then we get the people that say as long as the place is insulated rads are great.So when we go the plumb centre and asked for a 28kW boiler, 7 rads and oh give me 20 rolls of rockwool.Wheres the insulation in the rad manual.
I think the word you are looking for is "effective".
Efficiency is the ratio of output to input, as in your boiler example. The efficiency of a radiator is 100%.
You are really asking: what is the most effective way of heating a church?
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fuzzy
F
fuzzy
both, rads are not fires , they do not create instant heat, they are not designed to give instant radiated heat, a fire is. They are very effective, the heat rooms of all sizes if sized and situated correctly.
you make the point of the u value of the roof and the doors opening, thats not the fault of a radiator, it would be the same which ever heat emmitter you used.
If heat up time was a problem for you, would you not be better selecting a fan assisted convector possibly in conjunction with rads as many other designers of large areas use? regardless, the effieciency of the emmitter would be the same, although the comfort may be more like what your after
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fuzzy
i would install a combination of fan assisted convectors, radiators and were possible overhead convectors, all off the same boiler.
what is the total heat loss of the church? thats the first bit to get right
what is the total heat loss of the church? thats the first bit to get right
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