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Small Cabin Forum / Off-Grid Living / Water line size
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Link44
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# Posted: 13 Jun 2023 17:49 - Edited by: Link44
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Is there a water line size that will make it easier to use a mix valve for the shower?

I plan in using pex pipe to run lines and a Marey 2.64 gallon propane on demand water heater. I was wondering though would the size of the line help or hurt the ability to use the mix valve.

I don't have any of the parts yet so I suppose nows the time if 1 way is better than another.

Thanks

ICC
Member
# Posted: 13 Jun 2023 18:01 - Edited by: ICC
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Quoting: Link44
mix valve for the shower

By "mix valve", do you mean one of the typical single lever shower controls like this?

https://www.lowes.com/pd/KOHLER/5002595127

Those typically use 1/2” pipe/tubing though I use one in the rv-bis with 3/8" pex and a low flow head

FishHog
Member
# Posted: 13 Jun 2023 19:38
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just remember if your in a freezing climate those mix valves can hold water and freeze. I went with straight hot and cold water valves and realized for the shower I didn't need more than one line as we set temp on the hot water heater

Link44
Member
# Posted: 13 Jun 2023 20:32
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Yes, I was looking at mix valve options and a valve like that was 1 of them. Another was an actual 2 knob valve like what I have in my travel trailer. I don't know if 1 or the other would give better results.

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Link44
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# Posted: 13 Jun 2023 20:34
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FishHog, so you ran independent lines and valves? Do they then T together at the shower head?

ICC
Member
# Posted: 13 Jun 2023 22:00 - Edited by: ICC
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FishHog mentioned winterizing... which can be a critical necessity. Or not.

I plumbed my cabin system to include a built-in ViaAir air compressor (12 VDC). I have used a single-handle shower mixer valve and the compressor since 2008. The compressor works very well to blow out all the fixtures and lines. It is installed with a system of 1/4 turn valves to isolate sections and facilitate blowing out. I never have had a freezing problem. Plan ahead.

Link44
Member
# Posted: 13 Jun 2023 22:22
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I planned on drain valves at low points, like directly below the shower but adding the ability to blow out the lines is a good idea. The cabin will freeze in the winter for sure.

ICC, What water heater are you using?
20230318_105558.jpg
20230318_105558.jpg


spencerin
Member
# Posted: 13 Jun 2023 22:47
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The mix valves should tell you what size water lines to use, but they're usually 1/2". I wouldn't deviate from that if I were you.....

ICC
Member
# Posted: 14 Jun 2023 00:03 - Edited by: ICC
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Quoting: Link44
ICC, What water heater are you using?

I'm sorta old school.... use a Suburban RV water heater. 6 gallon tank. It is a direct ignition type. The ignition system runs off 12 VDC. No pilot light. When the water temperature drops it will fire up and run and shut off when hot.

I have it installed in the cabinet base under the sink and counter. I added 2 inches of foam insulation around all the tank sides on top of the foam insulation sleeve it comes with. The on-off control switch is mounted on the wall near the sink. The burner does not run much and the extra insulation holds heat pretty good. I'm sure it does use more propane than an on demand but I like it.

It is similar to the one I have used in my bus-rv for over 25 years. (not the same tank all that time. ) Except the bus also has a 120 VAC heater element that can be used on shore power instead of propane.

It does require a hole cut thru the cabin wall. I use the RV trim ring and access panel. I like it over any of the cheaper on demand heaters I looked at. Works well with a mixer valve shower to regulate water temperature just like at home.

That is a good amount of snow. This past winter we had even more build up at times.

Link44
Member
# Posted: 14 Jun 2023 00:58
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That sounds slick.

FishHog
Member
# Posted: 14 Jun 2023 07:55
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Quoting: Link44

FishHog, so you ran independent lines and valves? Do they then T together at the shower head?


Yes exactly just the old school hot tap and cold tap mixing to a shower head, but I haven't used the cold tap in 10 years.
Read up if you plan to use gravity to drain and winterize as many mixing valves won't drain. They need to be blown out our rv antifreeze added

Nobadays
Member
# Posted: 14 Jun 2023 08:37
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Yes, single handle mixing valves will retain water and freeze/break. Unfortunately that was what was installed in our cabin shower. The rest of the plumbing is all installed to drain to a central point where 2 valves can be opened and that will drain everything......( well except when I left a bellly in a line I repaired last fall with PEX and Sharkbite fittings! Yes PEX will freeze and split! Note to self: tie that line up so it drains next winter! )

As far as the shower mixing valve goes, it's less than a 10 minute job after draining the cabin to unscrew the dress ring, pull the retaining clip and then extract the cartridge. Haven't had to replaced it yet. PO told me to do this, he had it freeze and break.

Link44
Member
# Posted: 14 Jun 2023 16:53
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Do you think the gpm rating of the on demand waterheater could affect how sensitive it would be to mixing in cold water?

Would a larger flow capacity be less sensitive?

FishHog
Member
# Posted: 14 Jun 2023 17:49
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Quoting: Link44
Do you think the gpm rating of the on demand waterheater could affect how sensitive it would be to mixing in cold water?


yes, if you split the flow adding in cold, if the flow through your water heater goes too low the heat will shut off. Its a safety feature where it requires a minimum volume of water flowing through. So if your pump is on the edge, you may not have enough volume to add some cold in.

Link44
Member
# Posted: 19 Jun 2023 17:36
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I was having a thought, what do you think about using a mix valve designed for a bathtub and plumbing the line that would go to the tub spout to a drain valve for winterizing. Do you think that would drain it completely?

ICC
Member
# Posted: 19 Jun 2023 17:57 - Edited by: ICC
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Quoting: Link44
Do you think that would drain it completely?

I would not trust that without blowing air through the opened valve. A mixer has small spaces that can trap a little water; if that little bit freezes in the 'right" way, it can crack brass valve bodies.

As mentioned, I have had many years of excellent success blowing out both my shower mixer and kitchen sink mixer at the cabin. I have been doing the same thing with the rv/bus plumbing for even longer. Some folks prefer to dismantle the mixer and that is not that big a job. If you keep the required tools stored on hand, especially for that job there is no time lost while hunting for the right tools.

EDIT: Note that if you have any ball valves in a plumbing system when they are closed they likely have a captured slug of water inside the ball. That will freeze and crack brass valve bodies.

A friend installed 12 VDC sprinkler valves in the low points of his lines. When the close-up season arrives he activates the valves with a wind up timer switch. He has those installed on the sink p-traps as well. (there are p=traps available with a drain in the bottom; sometimes it takes a search to find them)

Link44
Member
# Posted: 20 Jun 2023 12:15
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ICC, do you have air line fitting plumbed in to the system? More than 1? I suppose it depends how big the water system is. I will have 1 sink, 1 toilet and 1 shower all within 10 or 12 feet total length apart.

jsahara24
Member
# Posted: 20 Jun 2023 14:40
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I have one air line fitting plumbed into the cold, and 1 into the hot. I turn down the pressure on my air compressor to ~30psi and then go around and turn on each faucet individually to blow it all out.

Once i'm done I go back and open up all the faucets so the system isn't pressurized.. Has worked for me and it only takes about 10 minutes...

ICC
Member
# Posted: 20 Jun 2023 15:35 - Edited by: ICC
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My cabin plumbing is laid out much like in an RV. I do not have a well.

The water storage is a buried cistern. Buried deep enough to not freeze in winter.

A submersible inline Rule pump is in the bottom of that cistern and when turned in from inside the cabin it pumps water into a 12 gallon RV fresh water tank under the kitchen counter. A Shurflo V 12 VDC water pressure pump takes water from the indoor tank and sends it to the water heater, sinks and shower.

I have a 12 VDC VIAIR 85P air compressor under the counter along with the Shurflo water pump and the 12 gallon fresh water tank.

The Shurflo has 1/2" metal pipe thread connector fittings added to the plastic threaded couplers the water pumps are sold with. My reason for that is I don't like plastic pipe fittings when there may be repeated removal and replacement of the threaded couplers, hoses, etc. It is too easy to mess up the threads.

The shurflo intake side is connected to a shut off valve on the fresh water tank. The output of the Shurflo feeds water to the entire balance of the system. That hose end has green tape wrapped around the end as an identifier.

Here is my winterizing drill.

I remove the Shurflo by disconnecting the in and out hoes. Then I turn the Shurflo on , tilt it and shake to be sure all water is expelled from the diaphragm pump head and the filter body that is permanently attached to the intake side. Turn it off and set aside.

The hose with the green color-coded end is then threaded onto the 1/2" male pipe end that I have fitted to the Viair compressor output hose. The compressor is turned on and then I go through much the same motions jsahara24 mentioned above. I start at the farthest distance, the shower mixer valve. Open, rotate through the handle's range and close. I repeat 2 or 3 times with the shower mixer, letting air pressure build up in the pipes. I can tell by the sound when the pressure has reached 50 or so PSI and open the water valve again.

Then I move to the kitchen faucet which is only a couple of feet from the air compressor.

I have no toilet at the cabin because we use a privy there. In the bus/rv there is a toilet but RV toilets are more like an on-off faucet as there is no toilet tank. If I was winterizing a standard toilet would probably blow out the toilet fill valve and fill the trap with RV antifreeze.

My water heater is an RV type. It has isolator valves (bypass system) so the tank is just drained outside by removing the anode rod plug.

With the RV water heater bypassed and draining on its own, the air compressor pressurizes everything and I do the blow out routine from furthest to closest three times to make myself content. Same thing with the bus/rv except there are more valve positions to blow out.

The fresh water storage tank under the counter has a valve and drain pipe to allow returning the water to the inground cistern.

When I am done I make sure the fresh water tank has emptied and then leave all valves in an open position. I mentioned that ball valves break if water is trapped in the ball when left in the closed position. I figure the same thing may happen if a bit of water was caught in a closed faucet so those are left open too.

I did my bus/rv a little differently with the air compressor being hard-plumbed using some extra valves and not having to switch hose ends. But I ended up wanting to remove and shake out the Shurflo well and had to undo the hoses to do that anyhow.

I hope that is not confusing. It works for me. No guarantees for anyone else.

travellerw
Member
# Posted: 20 Jun 2023 17:04
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Mixing valves can be a bugger to winterize unless blown out or filled with antifreeze. I used to be crazy anal on our RV and first low point drain, then blow with compressor, finally fill everything with RV antifreeze.

I have since stopped using the compressor and just low point drain, then fill with RV antifreeze (draining prevents dilution). However, the rest of my family just uses antifreeze and has never had an issue even when it get -40 here. I have plumbed my cabin the same way since its been working in my RV for like 18 years.

As to PEX line size. I don't think changing it will make any difference for the on demand heater. Just use the size recommended by the faucet manufacturer.

Link44
Member
# Posted: 20 Jun 2023 17:32
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Thank you all, I appreciate the detail and it was not confusing.

I have a 275 IBC tank we are using to supply water to our travel trailer now. I pull the shurflo out of the system and take the trailer off the mountain in the winter. The shurflo has it's own outside box with 12v battery and solar panel. It's set up like RV hookups basically. We drain any water from the tank and store it in the shed so snow doesn't crush it.

I think I'll be plumbing in a airline fitting and probably pull the pump for winter.

How do you fill a mix valve with rv antifreeze?

travellerw
Member
# Posted: 20 Jun 2023 19:03
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Quoting: Link44
How do you fill a mix valve with rv antifreeze?


You need a 3 way valve installed before your pump. When the valve is one way it sucks from your water tank. When you turn the valve the other way it sucks from an open port you put a hose on and stick it in a antifreeze bottle.

You stick the hose in the bottle and turn on the pump (with all the taps closed). Then you go to each tap and turn on cold until you see red antifreeze, then repeat for hot tap. Repeat for all your taps (don't forget the toilet). Boom, entire system filled with antifreeze and %100 protected. The antifreeze we buy here is good down to -60C before it will gell (not freeze). We use about 10L of antifreeze each season at a cost of about $20cdn.

(If you have a traditional hot water tank in your system, then it must have a bypass circuit installed so you can bypass it. Otherwise it will fill with antifreeze and cost you a fortune. If you have a tankless, many people will NOT bypass those and fill them as well for protection).

Link44
Member
# Posted: 20 Jun 2023 21:17
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travellerw, thanks for explanation that makes sense.

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