Saving hot water with a Heat Trap? Anti-Thermosyphoning

Xringer · 04-01-10, 06:15 PM

I've seen a few examples of this idea on the web. The hot water output is looped down (or up then down)
to trap hot water in the water heater and keep it from slowly flowing upwards from the heater to the pipes above it.

I'm thinking of using the double loop version when I do my new mixer install..

http://www.energycodes.gov/moodle/mo...iew.php?id=109

Since it's going to be PEX and not copper, not much cost involved..

What do you guys think? Good idea?

Thanks,
Rich

Daox · 04-01-10, 07:05 PM

Looks good to me.

Piwoslaw · 04-02-10, 10:58 AM

Is that enough to keep hot water form escaping from the tank? I thought it had to go back down to at least mid-tank before going up again.

Xringer · 04-02-10, 12:43 PM

It seems like the loops don't have to be below the tank..

It looks like the in-&-out lines on this one are from the wall behind the water heater..

My hot water comes from a coil inside of my heating boiler..

the In-&-Out is off the left, top rear of the boiler. So, I can add some heat trap loops
below the I/O and mount the new mixer above the top lid..

Daox · 11-12-10, 09:50 AM

Does anyone have any ideas how how big the trap should be? I'd like to do a quick and easy retrofit on my hot water heater with some PEX line.

Patrick · 11-12-10, 10:13 AM

I believe most of the newer heaters already have heat traps built into them (the 1994 model I just removed did). If yours doesn't, you can buy them at HomeDepot: Camco No. 1015 In. Heat Trap Dielectric Nipple - 15132 at The Home Depot

Xringer · 11-12-10, 10:15 AM

From looking at the pictures on the web, I don't think the loops have to be very big.

Energy Savers: Insulate Your Water Heater Tank for Energy Savings

The nice thing about PEX is the price.. So, you can use 6" loops are 18" loops
and the price will be almost the same.
Even with the cost of the extra pipe insulation tossed in..

When I do mine, I'm going to try for about 8" and use the 'feel' test to make sure it's enough.

Daox · 11-12-10, 10:17 AM

Quote:

Originally Posted by Patrick

I believe most of the newer heaters already have heat traps built into them (the 1994 model I just removed did). If yours doesn't, you can buy them at HomeDepot: Camco No. 1015 In. Heat Trap Dielectric Nipple - 15132 at The Home Depot

Interesting. How do those work?

Daox · 11-12-10, 10:18 AM

Quote:

Originally Posted by Xringer

From looking at the pictures on the web, I don't think the loops have to be very big.

Energy Savers: Insulate Your Water Heater Tank for Energy Savings

The nice thing about PEX is the price.. So, you can use 6" loops are 18" loops
and the price will be almost the same.
Even with the cost of the extra pipe insulation tossed in..

When I do mine, I'm going to try for about 8" and use the 'feel' test to make sure it's enough.

I'd imagine the better your pipe insulation, the larger the loops need to be as the conduction of heat through the water will allow the heat to travel farther 'down'.

Xringer · 11-12-10, 10:21 AM

Quote:

Originally Posted by Daox

Interesting. How do those work?

From what I've seen, they are just check-valves. One-way flow, so the water
can't back-flow..

Before you install anything, you need to test your input & output pipes to see
if they are indeed warming up.. If they aren't, you can forget this project..

04-01-10, 06:15 PM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	Saving hot water with a Heat Trap? Anti-Thermosyphoning I've seen a few examples of this idea on the web. The hot water output is looped down (or up then down) to trap hot water in the water heater and keep it from slowly flowing upwards from the heater to the pipes above it. I'm thinking of using the double loop version when I do my new mixer install.. http://www.energycodes.gov/moodle/mo...iew.php?id=109 Since it's going to be PEX and not copper, not much cost involved.. What do you guys think? Good idea? Thanks, Rich

04-01-10, 07:05 PM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Looks good to me. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-12-10, 09:50 AM	#5
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Does anyone have any ideas how how big the trap should be? I'd like to do a quick and easy retrofit on my hot water heater with some PEX line. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

04-02-10, 10:58 AM	#3
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 964 Thanks: 190 Thanked 111 Times in 87 Posts	Is that enough to keep hot water form escaping from the tank? I thought it had to go back down to at least mid-tank before going up again.

04-02-10, 12:43 PM	#4
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	It seems like the loops don't have to be below the tank.. It looks like the in-&-out lines on this one are from the wall behind the water heater.. My hot water comes from a coil inside of my heating boiler.. the In-&-Out is off the left, top rear of the boiler. So, I can add some heat trap loops below the I/O and mount the new mixer above the top lid..

11-12-10, 10:13 AM	#6
Patrick Apprentice EcoRenovator Join Date: Jul 2010 Location: East Coast of Florida, USA Posts: 149 Thanks: 2 Thanked 5 Times in 5 Posts	I believe most of the newer heaters already have heat traps built into them (the 1994 model I just removed did). If yours doesn't, you can buy them at HomeDepot: Camco No. 1015 In. Heat Trap Dielectric Nipple - 15132 at The Home Depot

11-12-10, 10:15 AM	#7
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	From looking at the pictures on the web, I don't think the loops have to be very big. Energy Savers: Insulate Your Water Heater Tank for Energy Savings The nice thing about PEX is the price.. So, you can use 6" loops are 18" loops and the price will be almost the same. Even with the cost of the extra pipe insulation tossed in.. When I do mine, I'm going to try for about 8" and use the 'feel' test to make sure it's enough.