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Posted by HeatPro on October 22, 2004 at 16:30:18:
In Reply to: Re: Home hotwater heat questions posted by Wesley D. Wuertz on October 22, 2004 at 12:12:26:
Let's try this again. I won't be able to copy the flash picture that is on the url to show you how to mark the butterfly valve (which can have a gate or wide port ball valve valve substituted there) but I can copy the words from:
http://64.226.150.132/hydronic/service/purgeair.htm
Small Tube System Air Purging
The concept of purging is to force air from one end of a series of pipes out the other.
Mark the original position of the balancing (butterfly) valves on the hex nut next to the slot. In the picture below, the slot is on the top left bulge of the fitting.
· You find purge and balance cocks soldered into the tubing that brings water through the radiation. The left-hand side of the picture has a little screw slot on top of the hex nut to turn the paddle inside the valve across the stream of water to partially close the valve. The slot indicates the position of the paddle inside.
THIS IS W?HERE T?HE FLASH PICTURE IS.
· The paddles are inside to force water from the least-resistance pipe on one circuit to the greater-resistance pipe length on another circuit. This is checked by turning the butterfly valve of the pipe length that has less than a 20F drop in temperature from beginning to end until the other length has a 20F drop, so there is even heat. If this was done properly when the system was adjusted for balanced flow, marking the position before moving the slot will let you return the slot to the balanced position.
Turn all the balancing valves so they close the pipes.
· Usually you turn a notch across the pipe with a screwdriver, but some models of balancing valves already have a handle. Make sure the pressure reducing valve is open to the system (Open the feed water valve from the cold water line near the boiler.) Open the boiler drain (purge valve) to let water out until the water runs clear of bubbles. On the picture above, the purge valve may be a boiler drain screwed into the tapping to the top right. Close the purge valve when the water runs clear of bubbles.
· In some instances, the pressure and flow may not be enough to purge water while allowing water to flow through the pressure reducing valve. A quick fill feature may be on the pressure reducing valve, a bypass might be fitted, or a hose fill might be required.
· Repeat in every loop.
· Reset the balancing valves to their original position.