I've been fiddling with a number of rads in our badly piped-up house over t he last few weeks to encourage some unenthusiastic radiators to start heati ng up. I've not got a thermometer to balance properly, so I'm largely just going through the process of throttling back the locksheild valves on the well behaved radiators until I start to achieve some balance. Largely nil effect so far (though some occasional glimpses of success).
However, it just occurred to me that the largest rad in the house is in fac t the wet UFH in our kitchen, and whilst that is nice and toasty and warm i t may well be the largest single drain on the supply.
The whole system is very imperfect. From a WB combi, we have effectively tw o zones - the UFH zone and the radiators. The hot spewing forth from the b oiler goes to the rads (presuming there is a call for heat from the thermos tat), and if there is also a call for heat from the thermostat for the UFH then that sucks up part of the supply too. When the main thermostat demand s no heat, the UFH thermostat has no live power supply, and therefore the U FH cannot call for heat in its own right - the UFH can only operate when th e main stat calls for it.
I'm sure this is far from ideal, but the consequence is that we have always set the thermostat for the UFH to demand heating whenever the rads are cal ling for it (by setting the UFH thermostat at the lowest level possible). We worked on the presumption that we always wanted some heat in the floor, and didn't consider that there might be some impact on the rest of the syst em.
Is there likely to be an impact? I *think* that the UF zone and the rad zo ne divert from one "T" of 15mm piping. There is a pump on the UFH, so I pr esume there is a maximum flow which it can possibly draw away from the rads - assuming the pump in the UFH is less powerful than the pump in the boile r.
Or am I barking up the wrong tree considering whether the UFH is having any impact at all on the balancing of the rest of the system?
TIA!
Matt