Mary Yugo <[email protected]> wrote:
> Perhaps if the thermocouple were in contact with or very close to a very > hot steam duct at the input end of the primary loop of the heat exchanger > it would have measurable effect? > Perhaps it would if it were very close, but it was not close. You can see in the photos it was a good distance away. The temperature was only 35°C after all. The inlet pipe full of steam was way hotter than that. Houkes is right. Live with it. I have measured the surface temperatures of steel pipes close to a boiler. The boiler was MUCH hotter than the water. The pipe surface was within a degree of the water temperature as shown on a dial thermometer nearby. Those braided pipes under the sink are remarkably well insulated. The pipes were about 7 to 10°C cooler than the water. However the steel nut holding the two pipes together (shown in photo) was a lot hotter than the pipes. I should have measured it. I could not touch it, whereas I could easily hold the braided pipe (56 or 57°C). Copper pipes under a sink are the least well insulated thing you can have. You should get some foam insulation. That saves a lot of money and the time it takes waiting around for the hot water. There is remarkable variation in temperature from one spot to another on that braided pipe. I do not know why. It is not an artifact of the thermocouple because both thermocouples agree when held at the same location. I thought it was because I did not have the thermocouples firmly pressed against the pipe but that does not appear to be the case. You do not find such variation in steel or copper pipes. By the way, an air bubble under the insulation will have no measurable effect. - Jed
