How to plumb all this stuff?
I’m nearly done with a house I’m building anbd I’ve run into an issue with plumbing together all the devices in my utility room. I have a geothermal heat pump with what they call a “desuperheater” that puts out warm water to the water heater, as well as a water softener for the hot water line, and a Laing AutoCirc2 hot water recirculation pump. The Laing unit provides instant hot water at all the faucets in the house and is plumbed like this :
I just don’t know what order the devices should be plumbed on the hot water line. I’m hoping the massive brain-power of this group can help me out with this, my plumber and HVAC guys are scratching their heads over it. Thanks guys!!!
Just like it says and shows... the valve goes under the sink furthest from the heater, bridging the hot and cold, and the pump goes on the water heater. Nothing else to do.
I can read a diagram, what I need to know is how the desuperheater and the water softener figure into this picture. Do they go before the recirc pump, after it, or what. Thanks for posting a reply, but I think you misunderstood what I'm looking for.
Yeah, guess so...
Great question, I'm waiting to see the answer that makes sure you aren't getting hot water fed through the cold taps. My house has an instant hot water system but uses a 3rd line and no pump. I love having instant hot water at all the showers.
How does the water circulate without a pump?
My water heater is in the basement and all the showers and other hot water outlets on the upper 2 floors. Hot water rises just like the old radiator heat systems and there is no need for a pump. The loops all have check valves so once a demand for a steady flow is made there is no back flow through the recirculating loops. I had planned on installing pumps and the system is plumbed with a location for them but as an experiment I hooked all 3 loops together and decided to let physics take a try and for 2 years I have never had a shortage of hot water waiting at any tap so the pumps never got installed. One less thing to need repair.
> I'm waiting to see the answer that makes sure you aren't getting hot water fed through the cold taps.
I doubt that there is one. It looks like this thing does a little pumping to push hot water thru a check valve at the farthest point, and back thru the cold lines. It's a really half-a**ed idea, and wastes energy, too. If I bought a house that had one, I'd unplug the pump immediately, and take it out fairly soon.
Are you building a new house? This schematic looks like the system for retrofitting hot water recirc. For new construction, why not run a dedicated return line for the hot water loop instead of using the valve and allowing warm water to raise the temperature in the cold water lines? This way you don't end up waiting for cold water!
Edited 8/3/2006 9:44 am ET by BrianP
That's an interesting system. If Johnny is at sink no 1, using the cold water, and that circulating pump comes on, it'll give a nice stream of hot water out the cold taps. Personally, I'd run, not walk, away from that system, but to each his own. It reminds me of a 3 lane highway in Quebec, where the center lane is a passing lane, available to either direction. It's pretty unnerving if you aren't used to it, and only very un nerving if you are used to it.
I'd put the desuperheater and water softener after the pump. If you didn't have this wacky circulation system, where would you put it?
Something's wrong with that drawing. There's no way for the water to circulate - The lines dead end at each fixture.
A hot water recirculating loop requires THREE sets of pipes. This one only has 2.
O.K. - Wait a minute - I think HammerHarry is right. If that valve at the end of the line lets water pass through it, it would fill the cold pipes up with hot water, wouldn't it?Or is there something I'm missing?
I don't want to know my worth - I want to know if what I do is worth it. [Jeanette Merrell]
Here's a blurb from the Laing website:
Q. When I open the cold water faucet at the sink under which the AUTOCIRC¯ system is installed what prevents hot water from the hot water supply line from coming out that faucet?
A. The pump housing has a built-in auto closure device which prevents water from the hot water line coming through the cold water faucet and vice versa. The only exception is that when the cold water faucet is opened during one of the intervals when the pump is running, warm water will be directed from the hot water line through the cold water faucet. The warm water flow, however, will last only a very short time and end once the water temperature in the hot water line reaches 95ºF, thereby shutting off the pump.
Q. Since water from the hot water line is being pumped into the cold water line will there be any prolonged period of warm water coming out of the cold water line?
A. No. Once the cold water faucet is opened any "warmish" water in the cold water line takes a very short time to dissipate before the normal cold water temperature arrives.
I kinda have to wonder if this system is all it says it is, so I'm going to make sure it's plumbed in a way to make it easily deleted.
Here's the website for the pump if you want to take a look. It's under AutoCirc, and the one I have (got it for $10 at an auction of a storage facility) is the AutoCirc2.
Thanks for you guys' input.
If you just have one hot water run in your house similar to the diagram you posted, then if you still can just run a 3dr line from the farthest fixture back to the hot water heater inlet side and install a check valve before connecting it to the inlet line. That WILL give you instant hot water and won't be heating up your cold taps. Will cost more than $10 but shouldn't break the bank.
This is a give/take system for "after the fact". It is not designed for new construction. At least i don't think so...as others have posted.
I installed the exact same one on a home about 6+ years ago because I was tired of waiting for the hot water come to the master bath room, which was the furthest fixture away from the water heater.
The Pump mounts under the sink fixture the furthest from the water heater. it will not send out scalding hot water through the cold water faucet because the pump works on a thermostat and the cold water supply tends to balance out the hat water going back. BUT, you will get warm water through the faucet on the cold side, at least for a moment or three. The hot side will not be totally hot, but will be quite warm, enough to wash your face and help to get a good start for not wasteing water if you want to take a bath/shower.
I never noticed a warm water problem on the cold side in the fixtures closer to the water heater. Nor did I notice a problem with warm water going into the toilet tank and causing condensation??? which could "maybe" be a problem in some areas climates.
They also come with a timer to help with running with the demand times of the day.