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Re: Hot Water Recirc with Insulated Lines -- is it really that inefficient / expensive?
The heatloss from the recirc loop is basically flow rate and insulation value.
A recirc loop is really nothing more than a hydronic loop as far a heat loss to the space.
It just turns into an open loop system when you turn on a faucet.
A recirc loop is really nothing more than a hydronic loop as far a heat loss to the space.
It just turns into an open loop system when you turn on a faucet.
hot_rod
1
Re: Hot Water Recirc with Insulated Lines -- is it really that inefficient / expensive?
Hi, Just to give some general info, I've been told that running a recirc system 24 hours a day, using uninsulated lines can triple your water heating bill. It will depend on lots of variables, so is only a general statement. For efficiency, demand controlled pumping is much better than any other approach when using trunk and branch plumbing. It has as much as 10% of the heat loss. Manifold plumbing is another approach that can work very well if you don't have really long runs, have decent water pressure and can keep the lines small in diameter. As a demonstration, I just plumbed a new home with 1/4" PEX and in worst case, it takes six seconds to get hot water.
Yours, Larry
Yours, Larry
Re: Hot Water Recirc with Insulated Lines -- is it really that inefficient / expensive?
Homeowner speaking here. I have an indirect water DHW storage tank plumbed off my oil fired boiler. I have a Grundfoss recirculating pump on my DHW. The water storage is about as far away from the kitchen sink as possible. I had Grundfoss pump system with a new PEX return line installed about 3 years ago. The supply in my house is copper. All the copper is insulated with foam tubing insulation. My copper plumbing is as old as the house which was built in 1960. The Grundfoss pump I had installed is an adaptive pump and over the course of the first week it “learns” your usage habits and builds schedules around that. So the pump does not run 24 hours a day . If it does not detect and usage for 24 hours it goes into vacation mode and does not run again till it detects usage. I have not noticed any real difference in my oil consumption but have noticed a reduction in water usage by having open the kitchen faucet for several minutes to get hot water. My dishwasher works better as well as it has a constant supply of hot water.
jimna01
2
Re: Hot Water Recirc with Insulated Lines -- is it really that inefficient / expensive?
Why not use a boiler with a boiler mate (indirect water heater) so that you can use all 4 baths at the same time if needed, and possibly have a better sized boiler for the space heating? I like the newer Viessmann as they have separate tappings to pipe straight to the water heater, this allows you to avoid a mixing valve for the radiant portion in most applications.
As for the recirc you have the right idea about it. It can be expensive, insulate the lines and reducing the amount of time you recirculate is the best way to make it cheaper. Another benefit of a tank is that you won't get any cold water sandwiching like you could with a combi without recirc, if you want hot water at the ready just do a short recirc time during used hours from your tank to get warm water in the pipes
As for the recirc you have the right idea about it. It can be expensive, insulate the lines and reducing the amount of time you recirculate is the best way to make it cheaper. Another benefit of a tank is that you won't get any cold water sandwiching like you could with a combi without recirc, if you want hot water at the ready just do a short recirc time during used hours from your tank to get warm water in the pipes
GGross
1
Re: Hot Water Recirc with Insulated Lines -- is it really that inefficient / expensive?
I installed a thermosiphon recirc at my house. Lucky that my fixtures were above the water heater; sloped the supply up towards the fixture, the return down towards the water heater. Don’t need a pump.
Inefficient is not the right word to use for a recirc. In my mind, it’s a convenience. Like the comfort of security cameras around your house, Siri to command your desires to, a Tesla in the driveway….You’ve got to pay to play.
Just keep it simple.
Just keep it simple.
Re: C terminal on Crown Boiler?
You need 3 wires from the boiler to the thermostat. If you have that you can hook up the Nest.
1.The "C" wire you are looking for is the "yellow" wire coming out of the transformer. According to the diagram there are 4 yellow wires and 1 red/yellow wire spliced together coming out of the transformer. You add the C wire coming from the nest terminal "C" to that group of wires.
2.The red wire on the Nest "R" terminal should connect to the BL wires coming out of the transformer (I don't know if BL is blue or black) It's probably Blue.
3. The W wire on the Nest gets connected to the BR (brown wire that goes to the coil of the Honeywell R8225B relay.
You can find the transformer , the relay and the thermostat in the last picture you posted.
remember electricity is color blind. You can use any color you want as long as it is connected to the correct spot on both ends
1.The "C" wire you are looking for is the "yellow" wire coming out of the transformer. According to the diagram there are 4 yellow wires and 1 red/yellow wire spliced together coming out of the transformer. You add the C wire coming from the nest terminal "C" to that group of wires.
2.The red wire on the Nest "R" terminal should connect to the BL wires coming out of the transformer (I don't know if BL is blue or black) It's probably Blue.
3. The W wire on the Nest gets connected to the BR (brown wire that goes to the coil of the Honeywell R8225B relay.
You can find the transformer , the relay and the thermostat in the last picture you posted.
remember electricity is color blind. You can use any color you want as long as it is connected to the correct spot on both ends
Re: LOCHINVAR NOBLE KEEPS NEEDING MANUAL RESET HELP!
You are attempting to run that boiler at full-tilt boogie i.e. "we are using the hot water all 4 people at once"--without adjusting all of the proper settings. You are also running your system pressure rather high at 25psi. It will blow off at 30psi.--be aware. The installer probably never put up the outdoor sensor. You are missing a major aspect of this boiler's ability to operate at full efficiency most of the time--especially when those "kids" aren't there. Post a few pictures of the general plumbing layout for more comprehensive help from this forum. Use the manual or get a service person to adjust the boiler to proper settings and adjust AGAIN after "kids" leave.
I see one glaring problem in the above descriptions. You have a manual reset upper limit at 190, but the automatic cutoff upper limit is at 200? Really? What was someone thinking? The automatic cutoff must be below the manual, or which one do you think will trip first?Exactly what was going on my mind yesterday too. Should I flip the manual to 200 and automatic at 190?
Please...
Re: Vacuum breaker for steam system
If they never see steam, couldn't they just be open pipes?Yes indeed they could -- and in a number of older systems they were (some were ven piped into the chimney, to allow the chimney to pull a slight vacuum!). It is better in modern systems to have actual vents on them (and in one or two old systems they are also needed for the proper functioning of the overpressure protection gadgets -- Hoffman Equipped for one) because many of those systems were designed to run on very low pressure, and people will crank up the pressure... which may, on some systems, cause steam to get into the dry return...
Re: Connecting Nest adapter on unusual boiler wiring.
If you have only 2 conductor wire (18-2) from the thermostat to the boiler room than you can add the NEST power converter the same way as you would connect the Nest Thermostat using the same instructions for the Red Jumper, the Yellow Wires from the limit to the LWCO and the three wires from the Nest Power Converter R W C as shown in this illustration. 
It is a little more than you may want to do so you may need a Nest Pro to install your thermostat and power converter if needed. If you are a fairly patient person with an aptitude for electrical circuits you may be able to DIY this one.
Feel free to ask any question. There are no stupid questions only ****** people who decide to not ask! You can PM me if needed
It is a little more than you may want to do so you may need a Nest Pro to install your thermostat and power converter if needed. If you are a fairly patient person with an aptitude for electrical circuits you may be able to DIY this one.
Feel free to ask any question. There are no stupid questions only ****** people who decide to not ask! You can PM me if needed
