Jeremy Harris

Just finished doing some more experimentation with the Chinese unit bought from eBay. I managed to decipher the Chinese characters for "salt", "gram" etc in the instructions and found that they seemed way off, 15g of salt for 300ml of water, with a probable electrical energy into the water of about 0.7 Wh. I tried this, but there was a massive excess of salt left in the solution. However, reducing the salt to 1.2g, seems to work, although at best it seems that the concentration of free chlorine is only a bit over 100ppm. I stabilised the pH with acetic acid (white vinegar) so that the starting pH (before electrolysis) was about 4. I used just a couple of drops of 70% concentrated acetic acid, but if using weaker white vinegar about 2ml might be needed to get the pH about right. This seems to work OK, and at this pH the solution should be pretty stable. From what I've read, anything over about 50ppm hypochlorous acid concentration is very effective as a disinfectant, so the ~100ppm solution that one of these units produces should be fine. It needs to be stored in a cool, dark, place, though, as heat and light will tend to cause it to breakdown more rapidly. In theory it should breakdown back to sodium chloride, so just plugging it in and giving it another burst of power should bring it back up to full strength again. The next stage is to try and get the bigger, home made version working. The plan is to get this to produce pure hypochlorous acid if I can, without the residual sodium hydroxide.

I've left a 9 litre/minute flow restrictor washer in our shower head. Hasn't been noticed yet . . .

I've had relays and power supply circuits fail in time switches. Right now the relay in our ~3 year old heating programmer is starting to fail. It sometimes doesn't switch on, and needs a hard tap to jar the relay enough to make it operate. I suspect these things are being "value engineered" to the point where long term reliability is starting to suffer. FWIW, I repaired a faulty relay in a time switch at our old house, and that was still working about ten years later when we sold the place. I strongly suspect that the brand name relay I used as a replacement was a great deal more reliable than the no-name bit of Chinese tat that was fitted originally.

Our experience, mirrored by others here, I think, has been that the ventilation rate given in Part F is higher than needed, rather than lower. We turned our MVHR down a bit, whilst monitoring air quality (RH and CO2 concentration) and haven't seen any detectable change from doing this. We can set four speeds on the MVHR, and run it on 2 (about 30%) most of the time, with 3 (about 70%) being the normal boost and 1 (about 10%) being a very low setting for times we go away. I don't think we've ever run it at speed 4 (100%) although it may ramp up to that automatically when the integral heat pump is running.

The only person I had to physically eject from our site was a labourer that I caught coming out of the portaloo, tucking a bottle of vodka back in his pocket. I'd found a couple of empty vodka bottles in the skip, and catching him red handed just confirmed my suspicion.

For a radial feeding outlets where part of the cable run is 2.5mm² the overload protection needs to be reduced from 32 A. Depends on the cable runs (derating if in insulation, etc) so the MCB needs to be either 16 A or 20 A most probably. Clipped direct 2.5mm² T&E is only rated at 27 A, which is OK for a 32 A ring final, where the assumption is that current will be shared around the ring, but not OK for a radial.

We have budget triple glazing that has a Uw of around 0.7 W/m2.K. The glazing units are mainly 4 - 20 - 4 - 20 - 4, with two low e coated panes and argon filling.

23.4°C in the house right now, and we've had no heating on for at least the past couple of weeks.

As I type this all three cooling systems are running again, the aircon in the bedroom, the floor cooling from the ASHP and the air cooling via the heat pump in the MVHR. It was sub-zero here last night, too, with a hard frost. Solar gain can be a real bugger at times.

Brickies are still working on sites around here. Drove past one the week before last and it looked very much like work was continuing as usual. I suspect there will be a stop on work before long, though, not because of the direct restrictions from the pandemic, but just because no one is buying new houses right now. I suspect that they will do as they did in the last recession, and start mothballing sites before long.

Yes, some of them can, just need to check the spec. They have the big advantage of a rapid response time, as they really chuck out a lot of air initially, when the difference between the set point and the room temperature is a degree or two. Ours slows right down once it's got the room to temperature, and is quiet enough that it doesn't disturb sleep on the few nights last year we kept it on. They are also pretty cheap, I detailed the cost of ours in this thread:

The one we had was like that, albeit in a slightly larger chamber (but it dealt with the whole house). Definitely orders of magnitude better than a macerator pump, like the Saniflo or similar, and virtually silent, which is a big plus. The macerator ones make a heck of a row, and because they are operated by a float switch they come on for any nocturnal trip to the loo, even if it isn't flushed.

Isn't that the truth! I tried to repair one once. Definitely up there with the Derek and Clive "worst job I ever had" rankings . . .

Yes that the thing. The macerator type units, like the Saniflo, are a complete nightmare by comparison. They are noisy and when they fail (as they will) they are the most singularly unpleasant thing to try and fix. We had a pump station at our house in Scotland, pumping up a few metres to the sewer in the road. Never a moments trouble, and ours was relatively easy to swap the pump if needed, as it had a chain to pull it up.

We have 500mm overhangs on our South facing glazing, totally useless, as the problem seasons are Spring and, to a lesser extent, Autumn, when the low sun projects deeply into the house. We fitted reflective film to the windows that made a big difference, but hasn't completely fixed the solar gain problem. With hindsight I should have opted for something far more effective at shutting out the heat. Ideally I'd have liked to fit external blinds, as these can be very effective at controlling solar gain, but it would have created yet more hassle with the planners. The other option we really should have looked at is Sage glass, as, despite the cost, that seems to work very well at reducing solar gain, too. Our ASHP runs a lot more in Spring and Summer than it does in winter, not heating the house, but cooling it. We run it in reverse so it pumps cool water around the underfloor heating pipes, something that is very effective. As we have PV panels in the roof, there is no cost associated with running the ASHP in cooling mode. Our ASHP rarely runs at anything other than it's very lowest speed. We also have a heat pump built in to the MVHR (a Genvex) and that makes a useful contribution to cooling the house. It's been running in cooling mode every day for the past few weeks, in this sunny weather. Finally, I fitted an additional split aircon system in our bedroom last year, and that's invaluable at keeping the bedroom cool. That's also been run every day for the past couple of weeks.

Not much infests oak, and once dried out they will probably be fine. We have a few oak framed buildings around here that have frames that are 400 to 500 years old, often exposed to the weather, with no preservatives, and they are still in pretty good condition. Rot after prolonged (as in decades) of constant damp is about the only thing that will attack oak. Even then it's often only the outer layers that get damaged.

It's only been up to 17°C here today, but plenty of sun, so the house is currently sitting at 23.5° with all three cooling systems running . . .

I took out a renovation policy to cover the final year of our build, when the house was built, the site was no longer a building site and all we needed was insurance to cover the rebuild cost plus the risks associated with the final fit out.

Another one that put in connection points for panel heaters upstairs but didn't fit them. All we have are towel rails in the bathrooms, on a timer so they come on morning and evening for an hour or two. We did find that our bedroom got a bit too warm, so I installed a split aircon unit last year. This works well, and has been in use a fair bit to cool the bedroom down over the past couple of weeks or so.

Our windows (made in Ireland) have frames that are made from finger jointed pine, so it must be available in quantity, at least in Ireland.

Dead easy to just do that winding resistance check. If it's a standard motor it will have three separate windings, with the start and end of each brought out as six wires.

My old 3 phase compressor had a similar starter arrangement, but had an automatic star/delta switch. It ran more slowly in star configuration for a second or two when starting, then speeded up as it switched to delta to run normally. Looking at the switchgear I'd say it was a pretty standard star-delta switch operated by that lever. Frankly I think I'd just bin all the old switchgear and wire it up to a VFD. Relatively cheap and makes the machine a heck of a lot more usable. I never use the gears on my lathe any more, just change the speed with the VFD as it's so much easier.

There's a fixed ~1.7 ratio between torque and speed between star and delta connections, so without additional windings (to change the value of Kv) there's no easy way to have either the same torque or speed when switching from star to delta. Motors produce ~1.7 times more torque, and ~1.7 times less rpm, when connected in star than they do when connected in delta. As there are the standard 6 wires coming out of the motor (three winding starts and three winding ends) it looks to be a pretty standard 3 phase motor, without any additional windings.

Get a second hand rotary converter and fit a star-delta starter to it and see what happens?

In all probability the motor is just a single speed motor that had a star-delta starter, as those motors have six wires coming from them. They use a DOL starter relay system, with the motor starting in star and then switching to delta as it spins up. As above, just wire it in delta using a VFD, should work OK.