Recent content by Roddy Young

How does an AAV allow air into a pressurised system?

I am puzzled to read that air gets into your system. If it's pressurised, air cannot get in. (That's like imagining a car tyre filling with water when you go through a puddle.....) Are you sure it has anti-corrosion additive? Maybe the "air" you have to bleed out is hydrogen.

When the diaphragm in the expansion vessel in our unvented sytem died, lots of black spots came through the hot taps. They were slimy, so maybe not the same as yours. We also noticed the water in the bath had a brown tint which was rust from inside the EV.

You'd need to find a trustworthy plumber who is prepared to order a spare (eg: https://www.ebay.co.uk/itm/252450280750) and between you carry the risk that it's compatible, correct part, etc.

There is no point putting the temperature on it. People might think that by setting it to say 20°, the room should be 20°. Only the temperature at the valve will be 20°. Who cares about that? I want a comfortable temperature in the room. With a radiator system, that might turn out to be 20° at...

Can anyone explain why my 2 watt christmas tree lights only have a G rating?

"so how can we integrate our homes, to increase comfort and reduce costs" You ask a general question to which there is a general answer: insulate and draughtproof. It really is that simple.......in new builds. A real challenge in older houses, though. We live in the south of Scotland, in a 10...

If you are able to, drill a smaller diameter hole right through the wall from the inside. Then go outside and drill half way through with the larger drill. Finally drill with the larger drill from the inside. Hopefully they should line up OK.

You only mention the exhaust. Both exhaust and intake should be on the same wall or roof about 2 metres apart. This prevents wind blowing into one without being "balanced" by the other.

Minor but important concept to grasp: a 100 Watt lightbulb gives out 100W of heat....... as does a 100W motor doing the mixing, a 100W old fashioned TV, etc. Anything doing its job within a closed box (house) emits heat and that heat goes into the box. The exception is something like a tumble...

It does seem counterintuitive but I guess someone at Rehau discovered it was good to circulate the water around the floors with their pump (imagine both boiler connections shut off....) and top up the temperature as needed by the bleed of hot water through the thermostatic valve bottom left...

You have had the pump itself checked, so if it's not working you will need to get a meter and check its supply. The red box should do the switching but it, in turn, needs a supply. Maybe that's not being provided by the controllers. Our controller is a long box with leds which light to indicate...

Hello, Our UFH is identical, also labelled Rehau. The boiler feed is to the bottom via the thermostatic valve as yours. The thermostatic head (bottom left) should be set to about 30 or 35 degrees. It has a capiliary tube going to a capsule at the right end of the lower Manifold feeder. One...

Air can only leave the room through your venting system if fresh air can also get into the room. Open a window in a nearby room and see if there's any difference. Opening a window in the bathroom itself will allow the fan to suck fresh air through without removing the moisture laden air. Roddy

We built our house 12 years ago, well insulated and airtight with a heat recovery ventilation system. Our builder had a lot of experience in low energy houses and underfloor heating was taken for granted. He was very keen, however, to reduce the thermal mass of the poured floors and so used...