[Greenbuilding] hot water

[Lawrence Lile]

I've had more trouble with spring checks than swing (gravity powered) checks.  

I have a small pump that pumps hot water to a coil in the furnace.  It was not able to overcome the backpressure of a spring check, and would hammer.  The spring check would open a little, some water would flow through, put the pump on a different point on it's pump curve, the pump would wimp out, then the spring check would close with a bang.  Whenever the pump started up it was Bang! Bang! Bang! Bang! I was not able to make the spring adjustment light enough to stop the problem.  I even took out the spring altogether and it still did it.  A swing check solved the problem. 


Spring checks have a much higher pressure drop than swing checks, since the spring is always trying to close the valve.  The swing check has to be installed horizontally to work, but they work quite well.  

There are a number of places in a solar system where a check valve can be useful.  A very small heat trap check valve can prevent thermosyphoning and wasting heat at night.  These are little plastic jobbies that aren't perfect seals, but are good enough to stop the gentle pressure of thermosyphoning but not enough to stop a wimpy little El Sid pump.  



--Lawrence Lile, 


> -----Original Message-----
> From: greenbuilding-bounces at lists.bioenergylists.org [mailto:greenbuilding-
> bounces at lists.bioenergylists.org] On Behalf Of bill.allen at verizon.net
> Sent: Tuesday, February 08, 2011 9:52 AM
> To: Clarke Olsen; Green Building
> Subject: Re: [Greenbuilding] hot water
> 
> Sorry, I can't help with the valve question...no experience in that area.
> 
> What is your source of water? I'm in the middle of the woods and was thinking
> about a rainwater harvesting system instead of drilling a well.  Can anyone
> comment pro or con on RWH systems, especially for drinking water?
> 
> Bill
> 
> ------Original Message------
> From: Clarke Olsen
> To: bill.allen at verizon.net
> To: Green Building
> Subject: Re: [Greenbuilding] hot water
> Sent: Feb 7, 2011 10:38 PM
> 
> Actually, that is my plan: two 6.5T kw demand heaters will be fed by
> water run through a 1,000 gal. tank in the basement which
> will be heated with solar panels. Even if it is only 70*f, the boost
> will be enough for a serious shower.
> Here's a concept on which I would like a second opinion: how to give
> priority to the shower when feeding the kitchen from the
> same demand heater. My thought is to put a spring check valve in the
> line to the kitchen. Not a flap valve, these valves can be
> used in any position, because a spring holds a gasket against the
> flow. With the pressure drop of an open faucet, water easily
> overpowers the spring and pushes past the gasket. But, if the
> pressure is low because water is flowing through the unchecked
> line to the shower, the spring should become a factor in the flow to
> the kitchen.
> Clarke Olsen
> 373 route 203
> Spencertown, NY 12165
> USA
> 518-392-4640
> colsen at fairpoint.net
> 
> 
> 
> 
> On Feb 7, 2011, at 7:03 PM, bill.allen at verizon.net wrote:
> 
> > ...So do you circulate solar pre-heated water to each of the on
> > demand heaters? How does solar pre-heated water work in this model?
> > Thanks,
> > Bill
> >
> > -----Original Message-----
> > From: Clarke Olsen <colsen at fairpoint.net>
> > Sender: greenbuilding-bounces at lists.bioenergylists.org
> > Date: Mon, 07 Feb 2011 18:52:40
> > To: Green Building<greenbuilding at lists.bioenergylists.org>
> > Reply-to: Green Building <greenbuilding at lists.bioenergylists.org>
> > Subject: Re: [Greenbuilding] hot water
> >
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