Central Heating F @ E tank feed pipe gets too hot

[Harry Bloomfield]

Anybody know where we've got to now?

Page 5, post #76

 

[Johntheo5]

It means, I think, that there is nothing wrong with the system, nor was there when the pump was pumping horizontally even though the condensation is a bit puzzling.

 

[dilalio]

the arrow on the brass body

Brass??

 

[Johntheo5]

Just thinking about the original thread re feed pipe getting too hot, maybe get another 5 pages?

Should the vent pipe get equally hot as the feed pipe?, just re stating my sums again, a 90L system with a mean (flow+return) water temperature as high as 60C should expand by 1.46L (1.62%), assuming all this at 60C gets into the F&E cistern then, and assuming 15L at 20C in a 30L cistern will result in a final temp of 24C, 15L @ 20C mixed with 1.46L at 60C, its difficult to think that a 15mm cold feed will recirculate enough to increase the cistern temp to 36C, I have 22MM and my cistern might increase its temp by a few degrees but no more even with the CH on for 16 hrs/day.
If the vent was blocked the system might still work OK but I wonder could this result in those higher temperatures?

 

[fixitflav]

Page 5, post #76

Ha-ha Harry

 

[Johntheo5]

View attachment 359193
Thank you all for your comments so far. Much appreciated.
This is the current "H" layout on my airing cupboard.
A bit more background.....
I recently had a new Vaillant ecoplus boiler fitted. I cleaned out the system properly had all the radiators (18) off and cleaned them thoroughly. Replaced all the airing cupboard plumbing and originally had the pump horizontal and obviously no air vent!
I was forced by legislation to get a "recommended" and "gas safe" person to fit the boiler or my insurance would be invalid. This person had trouble getting the water round the system and removing trapped air so he altered my pipework to make the pump vertical and stick in this air vent (on the wrong side of the pump).
True the water gets round ok and all the rads work fine. but the fact remains that hot water is still migrating up the 15mm pipe and making the header tank 36 degrees. Loads of tank condensation and annoying drips out the pipe.
I just find it a puzzle that the 15mm feed pipe gets very hot up to the ceiling but the overflow pipe only gets hot up about 12 inches.

One (last) question, does the 22mm vent pipe get equally hot up to the ceiling? or do you mean the vent pipe when you say "the overflow pipe only gets hot up about 12 inches."