Trapping water

johndeere1937

Good evening all. 
I'm still working on the installation of my gravity hot water system. I purchased a 30 gallon stainless steel tank I plan to use as my reservoir. Used all stainless weld in fittings to connect my supply, vent, and a sight glass. My idea may be silly but I want your input. I am planning on plumbing a trap in my vent before it exits the home. My thought is that this may aid in the loss of water due to evaporation. I figure the surface area of the water in a 3/4 inch pipe is far less than that of an 18 inch tank. Plus I thought the water in the trap would help contain the evaporation of water in the tank. Any thoughts? 


Thank you 

dko

Sounds more like trapping air. There are tank vents made for this purpose to help prevent evaporation and only open when needed.

If you don't mind, could you share your drawings/plans for your system? I'm sure there would be a number of people that wouldn't mind sharing their thoughts and advice concerning function and safety.

johndeere1937

johndeere1937

Just to clarify. This tank is not in an unheated hard to access area. Its in an area of the laundry room with vaulted ceilings. No chance of the trap water becoming frozen. Not sure how trapped air would be a concern here. Please explain. The trap should be above the operating level of the water and still allow expansion air to enter and system air to escape upon heating. Perhaps I'm missing something 

Mad Dog_2

This looks like an old school open hot water heating system.   What is the goal?  Mad Dog

johndeere1937

Thats exactly what it is Mad Dog. Was just wondering if having water in a trap might help to control the evaporation of water from the system while still allowing air to exit or enter the system for expansion and contraction. If it's not going to help at all I'll just run a straight vent pipe. Seems the water in the trap would help contain the water in the system but I may be wrong. Wouldn't take much to add but was wondering if anyone thought it may be helpful. 

              Thanks 

hot_rod

A common tank application in the UK still for open system expansion tanks. A company in Turkey manufacturers a lot of theses steel vessel that are still sold there. And installed in coils attic spaces, heavily insulated versions.
We had a rep from the UK on one of the Coffee with Caleffi webinars trying to explain why the are still being installed.
The UK is the largest boiler market in the world, although heat pumps are being used more and more. Thanks Russia!