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Posted by Heatpro on November 30, 2005 at 12:33:46:
In Reply to: Re: To HeatPro and Joe Brix posted by Dave on November 30, 2005 at 12:04:28:
: Forgive my confusion, but it sounds to me like there are 2 options.....
+++ There are more than that; but those suffice. The failure to realize that hot water heat piping arrangements are so flexible is one reason ducted air HVAC companies see warm air as superior.
: 1. Leave most of the piping the way it is and put a storage tank (with 1 inlet pipe and 1 outlet pipe) in the boiler loop that simply allows hot water from the boiler to pass through the tank essentially making the boiler a high mass boiler. All other manifolds/pumps would stay the same in this configuration. The downside of this would be we'd be sometimes passing hot water from the tank through a cooler boiler which would then extract/waste some of that heat.
+++ Well stated, yes.
: 2. If we wanted to fix the issue of the heat loss from the tank to a cool boiler, we could use a storage tank that has 2 inlets and 2 outlets. One set of inlet/outlets would be piped directly into the boiler loop. Then the existing supply manifold would attach to the second outlet on the tank and the existing return manifold would attach to the second inlet on the buffer tank.
+++ This other option is also available; although the existing piping passing through the buffer tank doesn't require another pair of stubs on the tank, nor does repiping to place the boiler off the tank and the system off the tank at the same time if it is the boiler manufacturers' tank with 2-inch stubs.
In this situation, wouldn't the individual zone circulators still do the function of having zone valves and also allow us not to have a second 0010 pump?
+++ Yes, the individual circulators do the same job as having a zone valve setup. By sealing the connection between the two stubs to the zones, one circulator on the supply stub can handle all the zones with one circulator and zone valves.
: I'm just trying to rework things and not have the plumber tear the whole system apart.
+++ As you already have invested in circulators, flow controls and relays for each zone, there is no cost benefit to changing to one circulator and 5 zone valves now.
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: If we did go the route of the second option, would it save significant money efficiency-wise over option 1?
+++ Probably not. Hopefully the boiler has a damper to limit heat lost up the chimney which was the cause of more than 15% loss in AFUE of pre 1980 boilers. The boiler heat is released to the boiler room. If the boiler room is within the house and under the other rooms it might not make that much difference in comparison to cost of repiping in a given time frame. Insulating the connective piping and having good insulation on the buffer tank might be a better investment.