Tom Posted March 27 Share Posted March 27 Am I going mad or did I read something on here recently about airtight tundishes? Search function doesn't cpome up with anything. Our UVC is going in now and the chap wants to install one fo these https://www.toolstation.com/osma-hepvo-pp-tundish-adaptor-kit-wt/p98120?store=RJ&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=null&pkw=null&pmt=null&gad_source=1&gclid=CjwKCAjwh4-wBhB3EiwAeJsppLV0sVazuV9u0Aor8J5kX5w_mP1RCZXzZY7-CLSO6EVl1x48HWfYvxoCP0gQAvD_BwE&gclsrc=aw.ds which doesn't seem too airtight to me. Can anyone put me out of my misery? Link to comment Share on other sites More sharing options...
stu w Posted March 27 Share Posted March 27 Mcalpine do a self sealing Tundish ? Link to comment Share on other sites More sharing options...
Tom Posted March 27 Author Share Posted March 27 (edited) This one? https://www.screwfix.com/p/mcalpine-tundish-19-23mm-x-19-23mm/5684V?tc=DA8&gad_source=1&gclid=CjwKCAjwh4-wBhB3EiwAeJsppOoNmoQrdFmiKuTRVnWhjt4znl0ka_q5qwHJ-E3ZDxPfHI4UNtL00BoCY1gQAvD_BwE&gclsrc=aw.ds Looks like can't be used as actual tundish for a UVC though, judging by the feedback Edited March 27 by Tom Link to comment Share on other sites More sharing options...
Dan F Posted March 27 Share Posted March 27 This is the one I saw mentioned somewhere I think. https://www.altecnic.co.uk/drytraptundish. Was it @TerryE that had a thread on these the other week? Link to comment Share on other sites More sharing options...
vfrdave Posted March 27 Share Posted March 27 More likely this one https://www.screwfix.com/p/mcalpine-mactun-2-tundish-with-self-closing-valve-15-22mm-x-1-1-4-/589JJ?tc=QA4&gad_source=1&gclid=CjwKCAjwh4-wBhB3EiwAeJsppH5gst-d9cNqO9Z6RB6RKNRk93fa6TM-DvVf98bnwQKCHjSOi02FgxoC4lMQAvD_BwE&gclsrc=aw.ds Link to comment Share on other sites More sharing options...
Tom Posted March 27 Author Share Posted March 27 Thanks both, are either of those actually room sealed though? Is that even possible with a tundish? Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 27 Share Posted March 27 37 minutes ago, Tom said: Thanks both, are either of those actually room sealed though? Is that even possible with a tundish? You are fine with either, as AT tests are a 50pa and not 'hurricane' levels. "As built" tests are done with water sat in traps, so this will be fine. You must consider that both negative and positive pressures occur, so a 'heave' in either direction will have differing effects; a 'suck' on a waterless trap will happen regardless, but not a 'blow'. These will only be momentary vs constant, and life goes on (even in a Passsivhaus) Same happens with MVHR, it becomes temporarily imbalanced when wind blows onto the fresh and exhaust. Worry about something more significant is my advice, after you have reflected on doing the best job possible. If you can connect to an internal SVP then I doubt any issue would ever occur. 1 Link to comment Share on other sites More sharing options...
Tom Posted March 27 Author Share Posted March 27 Thanks Nick, I'll let the plumber stick with his one then (https://www.toolstation.com/osma-hepvo-pp-tundish-adaptor-kit-wt/p98120?store=RJ&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=null&pkw=null&pmt=null&gad_source=1&gclid=CjwKCAjwh4-wBhB3EiwAeJsppLV0sVazuV9u0Aor8J5kX5w_mP1RCZXzZY7-CLSO6EVl1x48HWfYvxoCP0gQAvD_BwE&gclsrc=aw.ds ) as seems the same design as the McAlpine one. Right, bed, perchance to dream Link to comment Share on other sites More sharing options...
TerryE Posted March 30 Share Posted March 30 All plumbing done. You can just about see our tundish behind the new OSO UVC. The small extension to the consumer unit contains the 240VAC power relays to switch the Immersions and the slab Willis and pump. Everything neat and tidy. Jan is a happy lady. We've also had a couple of deep baths to celebrate. Still got to tidy the last power lead. The shelf above is my "network rack" 🤣 3 Link to comment Share on other sites More sharing options...
MikeSharp01 Posted March 30 Share Posted March 30 That looks very tidy that UVC. Link to comment Share on other sites More sharing options...
WisteriaMews Posted March 31 Share Posted March 31 Are you running the tank purely from solar / grid electricity, or do you have it connected to an ASHP. We have planning for a passive house and I was thinking of a Sunamp, but have been put off by all the stories and the price, so am now thinking of an OSO running from solar / off peak grid electricity. Link to comment Share on other sites More sharing options...
TerryE Posted March 31 Share Posted March 31 (edited) I have an all electric passive house. I use Octopus Agile and schedule the slab and DHW heating to take advantage of best prices. Search for my posts and blog entries for more details. Edited March 31 by TerryE 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 1 Share Posted April 1 23 hours ago, WisteriaMews said: but have been put off by all the stories and the price, Facts, not stories Prices for them is now utterly insane. These got rebranded Thermino to try and shake the troubled relationship, and also Aquafficient. Same box, rebranded. Saw another of these getting wheeled out of someone’s home a few weeks back, never to return, and an UVC going in; to relieve the owner from their long-suffering negative experience. Sunamp tried hard to wriggle out of replacing some of these failed units. When the clients sought my technical support, Sunamp then backed down and replaced (supply and fit) for free. Facts, not stories. 1 Link to comment Share on other sites More sharing options...
TerryE Posted April 1 Share Posted April 1 (edited) What is crazy is that in terms of physics and engineering it would be really easy for a lot of us slightly more IT oriented folk to "roll your own" using the basic approach used in the PV, but keep it real simple N × PCM cells in a well insulated otherwise passive box with water feed and out. Use a Willis or other reliable inline heater and basic circulation pump, one-way valves, etc. so that you can both do flow through and internal recirc for heating, plus the control board that I discussed in my recent Microcontroller based power switching topic (these sell on AliExpress for ~£50 and you can use a python-like language if you want to implement all of the control logic locally); this plus a couple of 20A SSRs. Keep all of the pump and pipework on the outside so it is easily maintainable, and so you don't need a ticket on advanced laparoscopic plumbing. 🤣 I'd be tempted to do this as a "fun" project except that I don't need this myself now, and I've got other stuff on the TODO list. Even suggesting it might get me a severe blast of dragon fire from someone very close to me. Marital harmony is far more important to me. 😇 Edited April 1 by TerryE 1 Link to comment Share on other sites More sharing options...
Alan Ambrose Posted April 2 Share Posted April 2 I obviously haven’t been paying attention: ‘PCM cells’? Link to comment Share on other sites More sharing options...
Alan Ambrose Posted April 2 Share Posted April 2 Oh I see - ‘phase change material’. Link to comment Share on other sites More sharing options...
Tom Posted April 2 Author Share Posted April 2 On 30/03/2024 at 19:27, TerryE said: All plumbing done. You can just about see our tundish behind the new OSO UVC. @TerryE double check re your tundish that it actually meets regs. Looks like this is the one I linked to here https://www.screwfix.com/p/mcalpine-tundish-19-23mm-x-19-23mm/5684v but looks like it doesn't meet regs as a tundish for a UVC Link to comment Share on other sites More sharing options...
TerryE Posted April 2 Share Posted April 2 (edited) @Tom, thanks for the heads-up. I'll double-check the manufacturers datasheet and discuss this with my plumber. If necessary, I will source a compliant alternative and get him to refit it. I'd need a double failure that is of both the following for the UVC to risk venting: so I don't view this as an immediate fix needed: A failure of one or both of the tank thermostat switches My CH / DHW control system will only power the Immersion circuits if the tank temperature (taken by a separate digital thermometer next to the tank thermostat) is below a configured set point. Yes,, these DS18B20s can fail, but I've never had one still respond to a reading request but suddenly start to report a value 30°C lower than previous readings . Moreover if the top of the tank was nearing boiling then both sensors would have to be miss-reporting. So on the scale of risk, I am a lot less concerned about this than flying on a 737-MAX 🙃 BTW, here is a brief plot of my HW sensors: Edited April 2 by TerryE Link to comment Share on other sites More sharing options...
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