MirandaPoth

The HW loop is on while we’re awake, typically 6am til 10pm. It’s off while we’re out (shopping, holidays, trips out - it turns off when our alarm is on). It’s a 250 litre tank and typically I guess we’re not using it all in a day (shower on for say 20 mins a day, a little washing up only as most goes in the dishwasher). (It’s a big tank because it’s a big house with a big bath and we didn’t want to run out when we have visitors!) We’re going to fit an electronic temperature sensor on the tank to see what it actually is - currently it has only the bimetallic strip one that links to the boiler. I guess we could replace it with one that could be controlled programmatically from our Home Assistant server, so that it could periodically heat it to the higher temperature.

VERY interesting. Thank very much @JohnMo. We actually have a hot water loop in our setup, I wonder if that is enough to ensure a full change of water every 24 hours thus avoiding stagnation?

Interesting! I will look that up. Thank you!

Thanks everyone for your input. The hot water tank is well insulated and to avoid legionnaires it's at 65-ish deg C. There isn't really space to partition the room unfortunately, we thought about that. Our 'several servers' are part of our smart home & audiovisual systems. The whole point for security, speed, cost etc etc is that they are on site so that as little as possible is reliant on cloud services. We are getting quotes for a small split AC system; as @Nickfromwales said, this is probably the best solution. Thanks Nick 🙂

Boiler, hot water storage tank, selection of HP switches, CCTV system, several servers, many small hubs for the smart home stuff, and the MVHR units itself. Hot water pipes are all lagged already, although there might be a few bits that aren't (valves, joints)

I've just checked the running temperature of the UDMPRO. It's running at 46 deg C, which is about 6 above spec

Hmm I see what you mean. However hubbie is an electronics engineer and is unhappy about it running that hot all the time. Plus we have to leave the plant room door ajar all the time otherwise it gets much hotter, which isn't ideal ...

Thanks very much for your reply. Yes we do have an MVHR extract in the room, but it doesn't help with the heat buildup in summer. We're hoping it won't pull too much air from the room but I take your point about knocking off the MVHR airflow balance. Yes it does seem like overkill, especially as the smallest split units I've found so far are about twice the size we need. Although it would be nice to have a cool room in the house, as we are lacking one at the moment! Not sure what other solutions to look at. Any ideas?

The 12.5m3 plant room containing our servers, switches, hubs etc in our passivhaus-standard home gets too hot (28-30 deg C). We want to install a small, efficient, ducted aircon unit to cool it down to around 20 deg C. Heating, air purification, dehumidification are not required as the MVHR takes care of those. Our water storage tank, boiler and MVHR unit are all in the same room (which probably accounts for the temperature lol). We built the house ourselves 5 years ago so would like to install it ourselves. It's an MBC timberframe with wide insulated walls, cladded/rendered on the outside. We can handle making the necessary holes in the walls. Is this doable, or should we get it professionally installed? Any suggestions as to type/make/model to choose? What else should we consider?

@Temp - thanks very much. I will reread said invoices and see what I can do!

Ahh, I suspected as much. Thanks both

Thanks Vivienz. Some (a lot) of these invoices are zero rated, but not all, perhaps because our connections were somewhat complicated! I wasn't sure if it was worth putting these in my VAT reclaim - I guess not.

I've tried several times over the last few days to call the 'National DIY Team' at the VAT office to ask them some questions about our VAT reclaim. Plus, the form says you have to ring them to find out what address to send your claim to. However, after all the autoattendants, I get a message saying basically 'sorry we're too busy to speak to you, please try later' and it hangs up. No option to hold, no answering machine, no other way to contact them. Somewhat annoying. Anyone else experienced this? It is just the time of year?

Can you claim the VAT back on building control services? I'm thinking not, as they're probably classed as non-claimable along with architects etc. ... (Sorry to do another post, I'm trying to get my posts up to 10 so I can see 'The Thread'!) Thanks in advance ?

Hello all, Can you claim for your gas and electric connections? (I'm posting partly so that I can get my posts up to 10 so I can see 'The Thread'!) Thanks in advance ?