Onoff Posted September 12, 2018 Share Posted September 12, 2018 (edited) Evening, me again! It seems that if the HW is on and the CH off the rads still get warm. Where should I start looking? System was basically this, I sketched up a bit neater the original drawing of the system: BUT...I added 4 rads upstairs then two 2-port valves after the 3 port to zone upstairs and downstairs: First thought is the 3-port is letting by but then so what to some degree as it the hot shouldn't get any further if the 2-port is closed. Looking in the above pic at the 2-port marked CH-Down, that feeds the 3/4" nominal bore single pipe CH downstairs. It goes from the bottom of this valve to the first rad in the run in 22mm copper via the red handled ball valve. Should I just change all 3 valves and be done with it? Would the gate valve to balance things have any effect? Cheers Edit: Return to boiler appears as hot as the flow from the pump of that helps. Return is the blue taped 28mm running left to right from the bottom of the cylinder: And viewed from the other side where the upstairs and downstairs CH returns join that pipe: Trying to measure pipe temps with a cheap laser thermometer and black insulation tape stuck on the copper pipes but readings all over the place! Edited September 12, 2018 by Onoff Link to comment Share on other sites More sharing options...
PeterW Posted September 12, 2018 Share Posted September 12, 2018 Can you draw in where the new 2 port valves are as it’s not 100% clear where the new system is connected Link to comment Share on other sites More sharing options...
Onoff Posted September 12, 2018 Author Share Posted September 12, 2018 15 minutes ago, PeterW said: Can you draw in where the new 2 port valves are as it’s not 100% clear where the new system is connected Cheers. Something like this then: Just boosted the HW tonight with both 2 ports off and that first rad on the downstairs single pipe run after the 2 port got really quite warm. Must be bypassing? Last rad on the single pipe system is stone cold. Link to comment Share on other sites More sharing options...
Tyke2 Posted September 13, 2018 Share Posted September 13, 2018 Hi I have a pretty conventional system in my current house. I have a similar issue. I'm not very heating savvy yet so excuse tha lack of correct terminology. When the DHW is on but heating is off the rads upstairs get warm . Obviously the closer to the head of the run the warmer it is. With mine I assume its the thermal store that heats and bleeds up to the rads, as there is no cut off valve stopping this. In the winter it is great, I leave the DHW on and the upstarirs rads just tick over and are luke warm, so it keeps off the chill. In summer I turn off all the upstairs rads and it seems to solve it. I spoke to a heating engineer and he said its common with my boiler to have a valve fitted on the hot outlet but I didn't bother. Link to comment Share on other sites More sharing options...
ProDave Posted September 13, 2018 Share Posted September 13, 2018 Your problem is a common return line. Hot return water will flow through that when the HW is on. Even with the valves shut, there is a convection path up through one radiator and back through another to further along the common return pipe. Don't under estimate where hot water will flow by convection. Th cure is completely separate the heating return and the hot water return so they only join much closer to the boiler way beyond where the radiators connect so when only HW is in there is no longer hot water flowing in the radiator return pipe. Common return is the work of the devil, done to save pipe but can cause unexpected problems. Link to comment Share on other sites More sharing options...
Ed Davies Posted September 13, 2018 Share Posted September 13, 2018 9 hours ago, Onoff said: Cheers. Something like this then: The upstairs radiators don't really connect directly to the common return, do they? I guess it's a matter of what was already there but dropping the three-port valve and just have three two-port valves (DHW coil, upstairs, downstairs) would be a lot easier to think about. 1 hour ago, ProDave said: h cure is completely separate the heating return and the hot water return Does anybody ever go to the lengths of adding a non-return valve for this separation? Link to comment Share on other sites More sharing options...
Onoff Posted September 28, 2018 Author Share Posted September 28, 2018 3-port valve looks pretty corroded - 3rd pic above. Try and push the lever from Auto to Man and it just flops about, no resistance whatsoever. Sure it should make that whirring noise that they do? Current valve is a Tower MP3-28C. Quite used to Tower tbh but thinking maybe switch to Honeywell as they seem "the" name for quality etc. Any other make to consider? Cheers Link to comment Share on other sites More sharing options...
ProDave Posted September 28, 2018 Share Posted September 28, 2018 Tower seem to be a Honewell clone, very similar pattern. Link to comment Share on other sites More sharing options...
Onoff Posted September 28, 2018 Author Share Posted September 28, 2018 (edited) 27 minutes ago, ProDave said: Tower seem to be a Honewell clone, very similar pattern. The replacement, generic motor / actuators say they'll fit either Tower or Honeywell. Names I'm seeing are Salus, Drayton, Danfoss, Siemens....etc Edited September 28, 2018 by Onoff Link to comment Share on other sites More sharing options...
Nickfromwales Posted September 28, 2018 Share Posted September 28, 2018 Honeywell every time for me. Danfoss second. Does your boiler do a pump overrun? Link to comment Share on other sites More sharing options...
Onoff Posted September 28, 2018 Author Share Posted September 28, 2018 (edited) 32 minutes ago, Nickfromwales said: Honeywell every time for me. Danfoss second. Does your boiler do a pump overrun? Erm.....? What's that then? Hell of a lot of different models. Needs to obviously do HW, CH or both. There's a: MPN V4044C1569U, any good? There was I think back on eBuild a thread on Honeywell 3-port valves. Edited September 28, 2018 by Onoff Link to comment Share on other sites More sharing options...
ProDave Posted September 28, 2018 Share Posted September 28, 2018 I would avoid Danfoss. In our last house the microswitches kept failing, some I replaced the switches, others I replaced the whole head if I could not be bothered with the fiddle. Honewell in our new house. Link to comment Share on other sites More sharing options...
Onoff Posted September 28, 2018 Author Share Posted September 28, 2018 (edited) 7 minutes ago, ProDave said: I would avoid Danfoss. In our last house the microswitches kept failing, some I replaced the switches, others I replaced the whole head if I could not be bothered with the fiddle. Honewell in our new house. I've replaced micro switches on these valves in the past. Something else too...capacitors? So I think I need a V4073A1088: https://www.honeywelluk.com/products/valves/motorised-valves/V4073A-Motorised-Midposition-Diverter-Valve/ Whoa! How much??? They're pricey! Edited September 28, 2018 by Onoff Link to comment Share on other sites More sharing options...
Onoff Posted September 29, 2018 Author Share Posted September 29, 2018 Why are Honeywell so much more expensive then than Tower? Like three times the price. Are the seals around the spindle better maybe as it's where it seems to be leaking on this Tower one I think rather than the compression fittings. Link to comment Share on other sites More sharing options...
PeterW Posted September 29, 2018 Share Posted September 29, 2018 Better brassware, better seals, made somewhere other than China..... Do you definitely need 28mm ..?? Link to comment Share on other sites More sharing options...
Onoff Posted September 29, 2018 Author Share Posted September 29, 2018 (edited) 2 hours ago, PeterW said: Better brassware, better seals, made somewhere other than China..... Do you definitely need 28mm ..?? I don't know tbh. Existing one is 28mm. It's 28mm from the boiler then to the pump, then to the AB port. A port is 28mm reducing to 22mm then teeing to the two 2-ports. The B port goes to the coil in the cylinder in 28mm. Edit: Just realised then this drawing is drawn wrong! It's deffo 28mm in / out of the cylinder as is the return after the balancing gate valve. I drew this years back from the hand drawn suppliers sketch in with the boiler bumpf. Never actually checked it matches what was there! Edited September 29, 2018 by Onoff Link to comment Share on other sites More sharing options...
Onoff Posted September 30, 2018 Author Share Posted September 30, 2018 @JSHarris, do you rate the Salus stuff, just saw your thread mention the Salus UFH actuator. Looking for an alternative to the Honeywell 28mm mid position valve that's mega bucks. Saw this: https://www.toolstation.com/shop/p24643? @Nickfromwales, Salus in your book? Not sure where they're made... Link to comment Share on other sites More sharing options...
Nickfromwales Posted September 30, 2018 Share Posted September 30, 2018 Salus used to be ? but their new stats look ok. I’d not risk it tbh. HW or Drayton for me. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted September 30, 2018 Share Posted September 30, 2018 22 minutes ago, Onoff said: @JSHarris, do you rate the Salus stuff, just saw your thread mention the Salus UFH actuator. Looking for an alternative to the Honeywell 28mm mid position valve that's mega bucks. Saw this: https://www.toolstation.com/shop/p24643? @Nickfromwales, Salus in your book? Not sure where they're made... I've no idea about Salus valves, as the only thing I've used by them is a stepper motor driven actuator. That works very well, but my experience with central heating valves in various houses over the years is that Honeywell have been far and away the most reliable. Link to comment Share on other sites More sharing options...
PeterW Posted October 2, 2018 Share Posted October 2, 2018 This one has industry standard motors https://www.bes.co.uk/motorised-mid-position-valve-3-port-28mm-17392 1 Link to comment Share on other sites More sharing options...
ProDave Posted October 2, 2018 Share Posted October 2, 2018 32 minutes ago, PeterW said: This one has industry standard motors https://www.bes.co.uk/motorised-mid-position-valve-3-port-28mm-17392 That looks like the Tower valve? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 2, 2018 Share Posted October 2, 2018 37 minutes ago, PeterW said: This one has industry standard motors https://www.bes.co.uk/motorised-mid-position-valve-3-port-28mm-17392 Cheaper than shoplifting ? Link to comment Share on other sites More sharing options...
Onoff Posted October 3, 2018 Author Share Posted October 3, 2018 (edited) Thanks for the BES link but tbh the Tower on there has already had a motor change with an "industry standard" one so I'm going to go a bit better quality and hope Drayton seals last longer. Edit: EXCEPT...the one on eBay I was going to buy has gone! Edited October 3, 2018 by Onoff Link to comment Share on other sites More sharing options...
PeterW Posted October 3, 2018 Share Posted October 3, 2018 You can buy four of those for the price of a Honeywell - what’s not to like ..?? Link to comment Share on other sites More sharing options...
Onoff Posted October 3, 2018 Author Share Posted October 3, 2018 6 minutes ago, PeterW said: You can buy four of those for the price of a Honeywell - what’s not to like ..?? I'll be draining down 4 times as often! Link to comment Share on other sites More sharing options...
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