One pipe gravity revisited

Jeff Perry_3

For anyone interested.... you may remember about a post I put up regarding a 1-pipe downfeed gravity system we came across. Several questions were regarding installing a new boiler, repiping the system and finding 1-1/2 TRV's. Well here's the update. The owner opted for us to convert the system into a 2-pipe gravity system so that when they had the resources it would be easier to change the boiler and use a circulator. It also would also even the heat out as the return of each rad connected right back into the drop coming from the attic. So as the water dropped toward the basement each rad received cooler and coller supply water. The top floor was stifling hot, the middle floor just right and the lowest floor was always cool. Just like the 3 bears and their porage.

We first chose a corner of the house and repiped it so that the 2-1/2" drop only picked up the 3 supplies of the 3 rads. We ran a new return stack and tied it into what was the return after it had picked up the last rad. We now had a dedicated supply and a dedicated return. After filling the system and turning it back on we came back the next day to see if it had worked. And it worked beautifully. So we have now repiping all 4 stacks.

And whoever hooked me up with Tunstall, Inc I thank you. We have ordered 4 custom 1-1/2" TRV's. They have already sent us 2 of them and they work great, even on a gravity system. The top floor is now much more comfortable.

What we haven't done yet is install the small new zone off the boiler that will be circulated. It will have cast iron rads. The gravity part of the house is so large that we feel when the circulator zone calls for heat the gravity zone will never feel any heat being produced. Besides, the addition is well insulated and the old house is not. Chances are when the addition calls the grav zone will already be calling anyay.



We'll see.



Jeff