On Friday, 15 February 2013 12:53:40 UTC, Andrew Mawson wrote:
"larkim" wrote in message

...



I've been fiddling with a number of rads in our badly piped-up house over

the last few weeks to encourage some unenthusiastic radiators to start

heating 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

fact the wet UFH in our kitchen, and whilst that is nice and toasty and

warm it may well be the largest single drain on the supply.



The whole system is very imperfect. From a WB combi, we have effectively

two zones - the UFH zone and the radiators. The hot spewing forth from the

boiler goes to the rads (presuming there is a call for heat from the

thermostat), 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 demands no heat, the UFH thermostat has no live power supply,

and therefore the UFH cannot call for heat in its own right - the UFH can

only operate when the 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

calling 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 system.



Is there likely to be an impact? I *think* that the UF zone and the rad

zone divert from one "T" of 15mm piping. There is a pump on the UFH, so I

presume 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

boiler.



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



Does the UFH not have a manifold with a mixing valve and a flow throttling

valve so that you can reduce its demand ?



AWEM

I presume it does, yes, so perhaps that might be an area to fiddle with to get the temps up.

Matt