Ideas on winterizing tankless water heater

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Small Cabin Forum / Cabin Construction / Ideas on winterizing tankless water heater


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Thunder9 Member	# Posted: 4 Jan 2013 04:17pm - Edited by: Thunder9 Reply We're getting ready to start our cabin build in the spring and have a few questions. I know I'll receive plenty of good options by asking my friends here. We're are going to use our cabin for 2 or 3 seasons a year. We do not plan on heating during the winter when we are not there. Considering a tankless heater but I'm wondering how would one winterize it when not using the cabin? Are they easy to drain? Should I remove it,this option seems like it would be a lot of work? I have not found any yet made with heat tape yet. Located in Michigan's UP so the temps. can be extreme. Thanks and I look forward to all your replies..

TheCabinCalls Member	# Posted: 4 Jan 2013 04:23pm Reply Check the manual. Some need to be drained and others don't. If yours is one that doesn't have protection and you can't locate a manual see below: So, how to prepare the heater for winter? • First you have to turn the electrical power and gas supply off. Turn the gas off by using the main valve on the gas supply line, and for the electricity unplug the power supply cord. If the unit has the display at the front of the unit, it should be black. • If your tankless heater was working, you still have some hot water inside the unit. Wait for a while until the it cools down. • Shut off the water supply on the main shut-off valve. • Open the taps so the system can drain and release the pressure from the plumbing system. • Disconnect incoming and outgoing water pipes from the tankless heater. • Remove the inlet water filter. • Use the bucket to collect the residual water. Make sure that it all drains from the system.

Thunder9 Member	# Posted: 4 Jan 2013 05:13pm Reply Haven't bought one yet, looking for info from those who already may have experience with them and what they might reccomend. Thanks for your reply though.

littlesalmon4 Member	# Posted: 4 Jan 2013 06:12pm Reply drain or fill with plumbing antifreeze. I just take mine home.

larry Member	# Posted: 5 Jan 2013 07:59pm Reply Thunder9 like you i too am in Michigan. i was looking at a tank less water heater but went with a tank heater because no one would honor the warranty because we were using well water. it was very easy to open the valve on the bottom of the tank to drain it.

jjlrrw Member	# Posted: 17 Jan 2013 10:58pm Reply We just completed the plumbing in our cabin a year ago last November and use the cabin year round. Because of space I went with a tankless mounted it above the toilet . There are draining instruction but I also had a small air compressor so I keep it under the sink and blow the lines out when we leave. Water heater was $260 only thing I would do different is have separate valves in the shower to better regulate the water temp. http://www.amazon.com/gp/product/B002Y0K6AI/ref=oh_details_o00_s00_i00

jaransont3 Member	# Posted: 18 Jan 2013 12:18am - Edited by: jaransont3 Reply jjlrrw, How do you like your Eccotemp? It is the same one we plan to use in our cabin in Minnesota. One other question, what its your water source and how is it fed to the Eccotemp heater? I guess that is two questions.

bldginsp	# Posted: 18 Jan 2013 12:11pm Reply The problem is that even if you drain your water lines, some water remains trapped in the passages in the heating element. Some units are designed to drain out with a plug on the unit. I think some have electric heating elements but that requires constant electricity. I agree with jjlrrw who blows out his lines with compressed air. Small air compressors are not too expensive, but you have to start your generator to charge it up. Easier than disassembling the heater and taking it home. Not sure how you would get antifreeze into the water pipes, but I'm sure it's possible. If you drink the water from the same lines you are putting poison in your water supply, though. Another problem is that if you use an exterior only water heater, and use it during the cold months, it could freeze at night while you sleep. So I need an interior type with a flu to carry the burnt gasses out. I decided on the Bosch 330 tankless. Uses a standard 'B' type vent, needs no electricity, has a standing pilot light lit by a Piezo, and then I'll blow it and all the lines out with an air compressor.

Thunder9 Member	# Posted: 18 Jan 2013 04:17pm Reply So if I unstand this correctly, I would need to put a valve in the line that I could open up where heated water comes out of the heater? Blowing the water back down the water inlet line so to speak?

bldginsp	# Posted: 18 Jan 2013 09:51pm Reply I think there are a bunch of ways you could do it, but the main idea is to blow out any and all lines that can't drain by gravity. Ideally, you could set up all your water lines at a slope and then outside the cabin at a low point, like in a concrete utility box (Christy box) you would have a valve that you open to drain the whole system. First you shut off the supply, open the drain valve, go inside and open all your faucets so air can get in and then it all drains downward. But there are several problems with this- first, can you configure all your pipes to flow downward? I can't just because of the configuration of my walls. Second, tankless water heaters trap water, and third, some other things trap water too like shower mixing valves. So where do you tie the air pressure into the line? Probably anywhere, since anywhere you put it will charge the whole system. Then you have to shut off the supply, and be able to open faucets or other valves in every point necessary in the system to drain all lengths of pipe and the water heater and whatever else. In my case, I'll put a drain valve in the Christy box outside with the supply shutoff, put a fitting for the compressor onto the cold water line in a convenient spot, say, right where the compressor is stored in the closet with the water heater, and then I'll have to instal a special valve and drain pipe after the little valve that feeds the toilet, because that section of pipe won't drain any other way. Then, before I leave, I shut off the supply, connect the compressor, then open and close all valves and faucets and shower mixing valve one after the other until each section of line is emptied. A little complicated but in a small cabin with only two sinks, a toilet and a shower it should become fairly routine. I type fast so watch out here comes some more. The building department where my cabin is located is very strong on getting people to do freeze protection of piping. Draining the whole system is less a priority for them than protecting the piping from freezing in buildings that are occupied all winter. They suggest locating no pipes in exterior walls even if insulated, if they must be in exterior walls located them toward the inside with proper insulation on the outside, use foam insulation on pipes wherever they may freeze, use elec. heater tape, etc. If you set up to drain the system, they want a 30" deep dry well with gravel in the bottom of your Christy box for it to drain. When I put in my water piping system on my 5 acres, I put in over 1000 feet of pipe in various branches to different locations. I tried to set it up to all drain to the lowest point. My property is on a hillside. But one section of pipe has a dip in it so it doesn't drain. It's poly pipe which is forgiving of freezing but the copper terminations and valving are less forgiving. So now when I leave in the fall I go through an elaborate procedure of opening valves in sequence to cause this one section to siphon. A little silly and perhaps unnecessary because the pipes are buried below the freeze line, but I prefer to be safe rather than sorry.

Thunder9 Member	# Posted: 19 Jan 2013 02:01pm Reply Wow! great reply bldginsp. Just the kind of info I'm looking for, much appriecated. The more questions I get answered, the more questions I have (scratching my head) lol. Our cabin will be built on a crawl,plan on water lines draining to a central location near the crawl access in the mudroom so to speak. I wonder how important it is having a mixing valve for the 1 shower we'll have? Then there is the question of using pex or copper lines. I'm told copper lines are easier to work with in regards to draining to a central location vs pex. Their also more expensive, however, with a small cabin how much more could it really be. Seems maybe I should ask myself if I just want to drain the lines and use copper and forget the mixing valve. Or use pex along with mixing valve for shower and blow the lines out with compressed air? Still have to drain the tankless heater. hmm...did I just answer my own question This may be beyond my skill level to perform. Maybe I should just consult and hire a plumber for this job.

Xplorer Member	# Posted: 19 Jan 2013 03:39pm Reply Oops, left mine at our cabin. Hope it was completely drained (maybe evaporated?)

bldginsp	# Posted: 19 Jan 2013 04:15pm Reply Pex is a cross linked polyethylene piping that will stand up to hot water. Regular poly pipe will not and should be used for cold only. Pex is controversial because of the additives they put in it in the process of making it cross linked, and heat resistant. Regular poly pipe is fairly inert stuff with few additives. I won't use Pex just cause I'm concerned about chemicals in food, water, etc. so I try to minimize that. Don't know why it would be harder to get Pex pipes to drain. They are far easier to install in walls than copper and can be routed any way you want. There have been some problems with joints on Pex and other poly pipe so I suggest you do not close off any joint in the pipe in the walls, use access doors wherever necessary. Mixing valves are now required in showers, at least here in CA, in order to, supposedly, prevent scalding if you turn the hot knob without turning the cold. If they are not required where you are, or you are not getting a permit and inspections, you might opt for separate valves. That will make draining easier. Sweating copper pipe is not a hard thing to do and requires minimum tools. Not beyond the skill level of anyone with a reasonable ability to use tools. The small amount of copper pipe you use won't cost a heck of a lot. There are three grades of copper pipe, K,L,and M. K is the thickest and used usually only in underground situations where maximum strength is needed. L is medium and used indoors. M is thinnest and used indoors. It's cheaper but many plumbers advise not to use it cause it's too thin. I won't use it. Remember to always ream your pipe after cuts. Hope this helps

MtnDon Member	# Posted: 19 Jan 2013 05:38pm Reply Quoting: bldginsp Mixing valves are now required in showers, at least here in CA, in order to, supposedly, prevent scalding if you turn the hot knob without turning the cold. I believe the entire US is covered by the need to use temperature regulated mixers for new work. We can still buy the old ones but the packaging is marked for repairs only or some such wording. The thing I like about them is the person in the shower gets a constant temperature when there is a sudden draw ob cold water, as in flushing a toilet.

jjlrrw Member	# Posted: 19 Jan 2013 11:45pm - Edited by: jjlrrw Reply Quoting: jaransont3 jjlrrw, How do you like your Eccotemp? It is the same one we plan to use in our cabin in Minnesota. One other question, what its your water source and how is it fed to the Eccotemp heater? I guess that is two questions. For the money we are very happy with it, it does require electric to vent. We have a 2" well in a pit. The water enters the cabin under the kitchen sink, I have a shut off valve and drain valve in the pit, a shut off valve under the sink and also a hot water line drain under the sink, this is also where I plumbed in the air compressor. I blow the lines out about three different times with faucets open, closed (to allow more air to blow through the water heater) it may be a bit of over kill but only takes about 10 minutes. Learned to unplug the heater as the air moving through it will cause it to think there is water flowing. We only use RV antifreeze for the drain traps and toilet. The only down side with the heater is my mixing valve for the shower, if the heater is adjusted at a good temperature for washing dishes then taking a shower you need to adjust and valve more towards cold reducing the amount of water flowing through the heater. One of two things can happen, 1) if the flow is too low the heater will shut off, 2) the slower the water flows through the heater the more it heats up it can then reach its maximum temp and shut off. when this happens well water is cold in the winter!!! I now have the temperature and gas regulator set that works good for both. Ideal it would be a bit hotter for the kitchen. Having separate valves I think I could turn on the Hot valve to max and adjust the temperature with the cold valve then I would always have max flow through the heater.

Buchanang Member	# Posted: 30 Oct 2019 03:06pm Reply Apologies for resurrecting an old thread but a few things I want to confirm. Our water lines are set up with a cold input, t off to our on demand h/w heater, with both lines going to 2 sinks and shower. I can blow out the cold line with no issue with the input and output shutoff on the h/w heater but I only have access to the h/w line THROUGH the heater. Is it ok to run air through it? Appreciate your help.

Fanman Member	# Posted: 30 Oct 2019 05:45pm Reply Our Bosch tankless heater is connected using steel braided hoses that came with the heater. Makes it easy to disconnect the heater. I blow it out in both directions and also disconnect the small lines connecting to the control valve and turbogenerator (no electric hookup, it generates its own electricity for the controls). 12 years and haven't had a problem yet. The rest of the cabin drains by gravity when I open the valves, I put a good slant on all the lines when I replumbed the entire cabin, the original plumbing was a mess.

Atlincabin Member	# Posted: 30 Oct 2019 08:04pm Reply I blow mine out from both directions. Should not be a problem if you blow it out through the cold water connection. On some (all?) of these, there is a drain that you can open with a screwdriver on the bottom of the unit to drain it without air. But I prefer to also put the compressed air through it.

offgrididaho Member	# Posted: 31 Oct 2019 01:23pm Reply Where do folks get their "compressed" air from? I have always been told you can't use a compressor because you can introduce oil into the plumbing through the compressor.

Atlincabin Member	# Posted: 31 Oct 2019 01:35pm Reply Depends on the compressor, I would think. A lot of the new ones are supposedly oilless. The old piston type, that are much quieter and probably more reliable, will use oil. Even so, the amount of oil introduced into the line when blowing out the system should be pretty minimal. Or you can just attach a piece of hose and blow it out with your lungs if it's not a big system.

MNCabinGuy Member	# Posted: 17 Dec 2019 09:26am - Edited by: MNCabinGuy Reply I was doing internet research on the idea of installing tankless water heater in my cabin in northern Minnesota and found this thread. Good info. So, for winterizing a setup with tankless water heater: to blow out all of the lines in the whole cabin and the w/h, can I just connect the compressor to the hot water valve that supplies my washing machine and run the air through the lines, opening each faucet in the cabin (both hot and cold sides) until just air comes out of both hot and cold at all of the faucets? Will this also evacuate the tankless water heater? Thanks, everyone!

cspot Member	# Posted: 17 Dec 2019 04:34pm Reply I run RV antifreeze through my system before I leave. Only takes about a gallon and it easy.

Fanman Member	# Posted: 17 Dec 2019 05:51pm Reply Read the manual that came with the heater; it should tell you how to winterize it. On mine, I (per the manual) disconnect the water hoses from it and one other small connection to its control valve, and blow it out with a small compressor that originally came with a spray painting rig. Draining the whole cabin and blowing out the heater takes less than 10 minutes.