I moved my mega-stor the other day and eliminated a zone valve and relay. It's on a seperate loop with its own circulator so I figure it doesn't need a zone valve. Now it seems to be thermosiphoning. I had the aquastat turned all the way down yet the water temp was about 120*F. The supply and return piping stayed hot even though the circ. was not running. I've never dealt with this issue before. Is it common? Any input would be appreciated.
Mega-stor Thermosiphoning ??
- Thread starter Steaming Pile
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Not familiar with Mega-store... I have a home built tank with an exchanger coil that will thermosiphon from time to time.
Use a check or pump with built in check or reinstall the zone valve
Use a check or pump with built in check or reinstall the zone valve
Quite possible. You may need check protection on the supply and return. A circ with a check built in and a flow check, zone valve, or spring check on the other side.
Hot goes to cold, always. So ghost flow is always possible. If the piping is short or the tank above the boiler is tends to increase the potential for ghost flows.
It is possible for this to happen in a single pipe also. Warmer water travels up the core and cooler falls around the outer layer.
hr
Hot goes to cold, always. So ghost flow is always possible. If the piping is short or the tank above the boiler is tends to increase the potential for ghost flows.
It is possible for this to happen in a single pipe also. Warmer water travels up the core and cooler falls around the outer layer.
hr
I always wondered how that worked. Never thought of coaxial flow. Sounds like one more thing that is easier to do with larger pipes.
Nofossil
Moderator Emeritus
The NoFossil rule of thermosiphoning:
Whether you expect thermosiphoning or not, you're probably wrong.
Works for me almost every time ;-)
Whether you expect thermosiphoning or not, you're probably wrong.
Works for me almost every time ;-)
Thanks for the input. I'll probably throw the zone valve back in this weekend. It was up around 140* yesterday so I shut it down just to be safe.
heaterman
Minister of Fire
Still Smokin’ said:
If it has a dedicated circ a better route may be to just install a check somewhere on the outlet side of it.
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