Bobbins Posted September 19 Share Posted September 19 I'm hoping someone can give me some advice about the UFH in our new home please. The only sign that it even exists is as per the photos. There's no separate thermostat and no obvious link to the boiler. I'm guessing it runs off a nearby radiator, but would have thought there might be a separate control or something somewhere, but there isn't. Not too sure how I would go about trying to fix this, or even if it would be possible for me to do anything other than getting a professional in! Thanks Link to comment Share on other sites More sharing options...
Temp Posted September 19 Share Posted September 19 Many UFH companies buy in some parts. What's written on the red knob? On a mixed UFH and Rad system my bet would be on a pipe becoming blocked by sludge over the summer due to a lack of corrosion inhibitor. The standard way to deal with that is usually to turn off all rads except one. See if the pump can push water through that rad/loop. If it gets hot turn that one off and another one on. Repeat until you have detected them all get hot including the problem rad/loop. Turning them off and on can mess with the balancing so try and note down how many turns are needed to shut off each rad so you can put it back roughly as it was later. If that works I'd still consider draining down the system to remove any sludge you stirred up or you may have same problem next summer. Drain and fill the system a few times then put in corrosion inhibitor like Fernox F1 when you fill it for the last time. Ideally measure how much water comes out when draining so you can calculate how much Fernox to put in to achieve the right concentration. See the bottle. Apparently putting in a bit too much is ok. More than one bottle maybe needed. If the above doesn't work then you're into trying to connect a mains pressure hose to the blocked loop by disconnecting it somewhere. This can be very messy if hoses become disconnected so take care. Link to comment Share on other sites More sharing options...
ProDave Posted September 20 Share Posted September 20 The obvious thing from the photos is that thermostatic valve is turned down to minimum. Turn it up to max and tell us more about what you find. When the system is running and the radiators are hot, do any of the grey pipes get hot? And remember UFH works slowly especially when turned on from cold, it is likely to be a couple of hours at least before you feel any warmth in the floor. Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 Thanks so much Temp and ProDave for your comments. The red knob says Hep20, am attaching a photo showing the detail. And unfortunately the thermostat isn't even attached to anything! Not sure if it's broken or if a part is missing? Link to comment Share on other sites More sharing options...
ProDave Posted September 20 Share Posted September 20 I suspect that thermostat knob is supposed to connect to the grey bit on the left hand pipe, looks like a TRV for the UFH? Not seen one like that before but if it is supposed the be attached but is not it could explain why not working. Will it just clip on like a radiator TRV does? What was the thermostat in the original post that appeared to be mounded on a wall? Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 Yes it's the same thermostat in the original post. There's no obvious way to clip it on to anything, the grey bit on the left hand pipe is too slim and smooth for it to be able to attach there. It's a bit of a mystery! Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 Have been able to identify this part online, which feels like progress! Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 This is the blurb: Link to comment Share on other sites More sharing options...
ProDave Posted September 20 Share Posted September 20 Shame you have to buy the whole lot just to replace the broken / missing bits but that would be your easiest solution. Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 It is a shame but as you say will be the easiest solution. Would be great to get it working, as think it will be pretty chilly in the winter without it! Thanks for your help! Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 QQ, is there something a bit more 'standard' that could be used to replace the Danfoss FHR? Rather than buying a direct replacement? Link to comment Share on other sites More sharing options...
ProDave Posted September 20 Share Posted September 20 31 minutes ago, Bobbins said: QQ, is there something a bit more 'standard' that could be used to replace the Danfoss FHR? Rather than buying a direct replacement? A 2 port motorised valve and a room thermostat wired or wireless, but you will need a power supply to that area for it. 1 Link to comment Share on other sites More sharing options...
Bobbins Posted September 20 Author Share Posted September 20 Thanks for the quick reply ProDave, really appreciate your help! I’ll have a look into the 2 port motorised valve for sure, as have power close by Link to comment Share on other sites More sharing options...
JohnMo Posted September 20 Share Posted September 20 I would be careful just fitting a 2 port valve and thermostat as the original functionality of the system is lost a d you then zero means to protect the floor from excessive temperature. Is the grey cone bit just a tamper proof cover, fitted instead of the thermostat knob? Instructions attached AI000086447883en-US0201.pdf 1 Link to comment Share on other sites More sharing options...
Temp Posted September 21 Share Posted September 21 (edited) Looking at the instructions @JohnMo posted... I'm wondering if the stat is shipped with a temporary cap on the spindle to protect it and perhaps this temporary cap has been put back on when the knob was removed? Edited September 21 by Temp Link to comment Share on other sites More sharing options...
dpmiller Posted September 21 Share Posted September 21 ^ this. Link to comment Share on other sites More sharing options...
Bobbins Posted September 21 Author Share Posted September 21 Thank you @JohnMo, @Temp, @dpmiller for the responses. A temporary cap makes perfect sense... but unfortunately it will not budge. I'm thinking my best option may be to buy a new unit and start again. Really grateful for everyone's help, I feel I know so much more than I did a couple of days ago! Link to comment Share on other sites More sharing options...
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