best way to connect RO/DI to hot water heater

Matt850 · 01/28/2010, 11:52 AM

I currently have my RO/DI hooked up under the sink in my kitchen. My wife is a bit angry that it takes up most of that space and I have to have a jug for the water on the counter next to the sink to fill up which takes up even more space. I am not a huge do-it-yourself-er. My questions are:
1) Is there a good place to see step by step how to hook up my RO/DI to a hot water heater?
2) Hot water pipe or cold?
3) Am I in danger of the RO/DI bursting since the storage room with the hot water heater is not heated? (NC, temps can drop below freezing a few weeks of the year)

r-balljunkie · 01/28/2010, 01:09 PM

what about the laundry room? you could make a shelf up high and put your whole system up there, drain to the washers drain area. nice and tidy.

DC_40gallon · 01/28/2010, 01:36 PM

if you hook up ANY ro/di unit to a hot water line, you will immediately roast your membrane and your unit will be worthless.

$60-80 for a new membrane - don't make that mistake.

Does it ever get below freezing in that area of your house?? It might get cool but shouldn't get that cold!!

COLD WATER LINE ONLY!!

James77 · 01/28/2010, 01:36 PM

1- use a saddle piercing valve on any standard copper water pipe in your house

2- cold water ONLY, you will ruin it with hot water

3-if the storage room goes below freezing, I would not put the RO/DI there. What temp does it go to?

hammmerhead · 01/28/2010, 04:01 PM

Quote:

Originally Posted by Matt850

I currently have my RO/DI hooked up under the sink in my kitchen. My wife is a bit angry that it takes up most of that space and I have to have a jug for the water on the counter next to the sink to fill up which takes up even more space. I am not a huge do-it-yourself-er. My questions are:
1) Is there a good place to see step by step how to hook up my RO/DI to a hot water heater?
2) Hot water pipe or cold?
3) Am I in danger of the RO/DI bursting since the storage room with the hot water heater is not heated? (NC, temps can drop below freezing a few weeks of the year)

Go ahead and spend a little money and have a plumber cut the cold side on the water heater. Make sure he puts you a master shut off on it. Dont cut any corners by tapping the line, its just not worth the risk.

Rballjunkies idea is good too and would be easier. Just feed the RO off of the cold side of the washer in the laundry room. Just put a quality shut off valve feeding the RO filter.

Jade · 01/28/2010, 05:25 PM

Quote:

Originally Posted by DC_40gallon

if you hook up ANY ro/di unit to a hot water line, you will immediately roast your membrane and your unit will be worthless.

$60-80 for a new membrane - don't make that mistake.

Does it ever get below freezing in that area of your house?? It might get cool but shouldn't get that cold!!

COLD WATER LINE ONLY!!

Why cold water only??? My directions that came with my Filter Guys RO/DI unit says optimum water temp of 77 for best membrane performence. I run a mix of hot and cold.

CorkPullerPHL · 01/28/2010, 06:08 PM

Because Hot Water Heaters hold water at a minimum of 120F. 120F will fry the membrane.

I use the cold water line that feeds the sink next to the washer. I then put my RO/DI container in the sink. This prevents me from flooding the house when i forget to turn the unit off.

I use one of these:

http://www.bulkreefsupply.com/store/...g-fittings?p=3

reefergeorge · 01/28/2010, 06:35 PM

Quote:

Originally Posted by Jade

Why cold water only??? My directions that came with my Filter Guys RO/DI unit says optimum water temp of 77 for best membrane performence. I run a mix of hot and cold.

Because you will never get a steady temp with the flow rate our units run.
I have seen people fill a bucket with warm water, and run the incoming cold line through a coil or ro tubing in the bucket. That will safely raise the temp..

Matt850 · 01/28/2010, 07:40 PM

Wow, more response than I expected. I only mentioned hot water section due to reading another forum... i also realize now that the temp coming out of my hot water heater is around 125 degrees which would indeed mess up my unit. The temps this weekend get about as cold as it will and its going to be in the middle teens, which I suppose would mean I would have to remove the unit from that area and store it when it got down below freezing. I think that I still want to run it off the hot water heater (cold) and run it to a large trash can for mixing water. I was trying to make a setup to help ease water changes since it has to be moved anyways. Do you think it is possible that the hot water heater would be able to pump water off the cold line and up to my 2nd floor? It is unfinished and would be much easier with access from inside the house. I also have a drain pipe that was installed with the house in case someone wanted to finish the upstairs... it has all the plumbing (I believe) for an additional bathroom. The temp stays much warmer there than outside yet cooler than the house (non-heated). and not below freezing.

JimmyK · 01/29/2010, 12:54 AM

I run mine off hot water tank cold side as stated above. Everyone pressure is different but you can always tap tank run line and test with presure gauge (assuming unit has one). I bet it would work for you. Someone correct if wrong but unless presure is horrible won't it just take longer to make ro/di?

wooden_reefer · 01/29/2010, 11:34 AM

Quote:

Originally Posted by Matt850

I currently have my RO/DI hooked up under the sink in my kitchen. My wife is a bit angry that it takes up most of that space and I have to have a jug for the water on the counter next to the sink to fill up which takes up even more space. I am not a huge do-it-yourself-er. My questions are:
1) Is there a good place to see step by step how to hook up my RO/DI to a hot water heater?
2) Hot water pipe or cold?
3) Am I in danger of the RO/DI bursting since the storage room with the hot water heater is not heated? (NC, temps can drop below freezing a few weeks of the year)

RO is routed to instantaneous water heater generally small for drinking water.

In general, for tap water, the inlet vlv should be open so that when the water heats up no pressure is built up in the tank. The pressure relief vlv is an added safety if someone were to shut the inlet vlv to the water heater when the water is heated.

Make sure you do not shut off the inlet vlv into the RO. This is hard to do since RO unit has an automatic shut off when there is no more flow of RO water, otherwise the RO will run all the time even if you are not using any RO water.

May be an additional relief vlv of low treshold is a good idea, but may be the RO unit will be ruined with tubing bursting before the water tank would explode.

cabanaboy1218 · 01/31/2011, 06:11 PM

what if you run 30g hot water through it?

ramanbhalla · 09/22/2020, 06:10 AM

If you're feeding the RO/DI unit from a cold water line, then it doesn't really matter where the source comes from. You could even put a tee between your toilet and its water source. As long as it's cold water. You cannot, however, feed an RO/DI system from a hot water line. Your thread title says that the water source for your RO/DI would come from your water heater. This will ruin the RO membrane in short order. As long as you source the water from the cold water input, the one that goes into the hot water heater, then that would be a fine option. check out the best portable water heater reviews to know what are the best water heaters available in the market.

Vinny Kreyling · 09/22/2020, 10:21 AM

RO units should be connected to COLD water supply ONLY.
HOT WATER WILL RUIN YOUR MEMBRANE

Opus123 · 09/24/2020, 10:39 AM

Quote:

Originally Posted by Vinny Kreyling

RO units should be connected to COLD water supply ONLY.
HOT WATER WILL RUIN YOUR MEMBRANE

Did you realize you were replying to a 9 year old thread?

Vinny Kreyling · 09/24/2020, 12:26 PM

NO but it deserved repeating.

01/28/2010, 11:52 AM	#1
Matt850 Registered Member Join Date: Apr 2008 Location: Raleigh, NC Posts: 260	best way to connect RO/DI to hot water heater I currently have my RO/DI hooked up under the sink in my kitchen. My wife is a bit angry that it takes up most of that space and I have to have a jug for the water on the counter next to the sink to fill up which takes up even more space. I am not a huge do-it-yourself-er. My questions are: 1) Is there a good place to see step by step how to hook up my RO/DI to a hot water heater? 2) Hot water pipe or cold? 3) Am I in danger of the RO/DI bursting since the storage room with the hot water heater is not heated? (NC, temps can drop below freezing a few weeks of the year)

01/28/2010, 01:36 PM	#4
James77 Registered Member Join Date: Aug 2005 Location: Rhode Island Posts: 8,158	1- use a saddle piercing valve on any standard copper water pipe in your house 2- cold water ONLY, you will ruin it with hot water 3-if the storage room goes below freezing, I would not put the RO/DI there. What temp does it go to? __________________ Jim Current Tank Info: 120g Mixed Reef and 75g Freshwater

01/28/2010, 06:08 PM	#7
CorkPullerPHL Mmm, Beer. Join Date: Jul 2008 Location: Exton, Pa Posts: 563	Because Hot Water Heaters hold water at a minimum of 120F. 120F will fry the membrane. I use the cold water line that feeds the sink next to the washer. I then put my RO/DI container in the sink. This prevents me from flooding the house when i forget to turn the unit off. I use one of these: http://www.bulkreefsupply.com/store/...g-fittings?p=3 __________________ It has always been my private conviction that any man who puts his intelligence up against a fish and loses had it coming. - John Steinbeck Current Tank Info: Build on hold - Getting married instead.

09/22/2020, 10:21 AM	#14
Vinny Kreyling Registered Member Join Date: Nov 2002 Location: Miller Place, NY Posts: 7,206	RO units should be connected to COLD water supply ONLY. HOT WATER WILL RUIN YOUR MEMBRANE __________________ 250 gallon mixed reef, 2 Reefbreeder's Photon V 2, Deepwater BLDC 12, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 6 Tunze pumps.

09/24/2020, 12:26 PM	#16
Vinny Kreyling Registered Member Join Date: Nov 2002 Location: Miller Place, NY Posts: 7,206	NO but it deserved repeating. __________________ 250 gallon mixed reef, 2 Reefbreeder's Photon V 2, Deepwater BLDC 12, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 6 Tunze pumps.

01/28/2010, 01:09 PM	#2
r-balljunkie Registered Reefer Join Date: Jun 2007 Location: Doha, Qatar Posts: 2,059	what about the laundry room? you could make a shelf up high and put your whole system up there, drain to the washers drain area. nice and tidy.

01/28/2010, 01:36 PM	#3
DC_40gallon Registered Member Join Date: Sep 2009 Posts: 1,474	if you hook up ANY ro/di unit to a hot water line, you will immediately roast your membrane and your unit will be worthless. $60-80 for a new membrane - don't make that mistake. Does it ever get below freezing in that area of your house?? It might get cool but shouldn't get that cold!! COLD WATER LINE ONLY!!

01/28/2010, 07:40 PM	#9
Matt850 Registered Member Join Date: Apr 2008 Location: Raleigh, NC Posts: 260	Wow, more response than I expected. I only mentioned hot water section due to reading another forum... i also realize now that the temp coming out of my hot water heater is around 125 degrees which would indeed mess up my unit. The temps this weekend get about as cold as it will and its going to be in the middle teens, which I suppose would mean I would have to remove the unit from that area and store it when it got down below freezing. I think that I still want to run it off the hot water heater (cold) and run it to a large trash can for mixing water. I was trying to make a setup to help ease water changes since it has to be moved anyways. Do you think it is possible that the hot water heater would be able to pump water off the cold line and up to my 2nd floor? It is unfinished and would be much easier with access from inside the house. I also have a drain pipe that was installed with the house in case someone wanted to finish the upstairs... it has all the plumbing (I believe) for an additional bathroom. The temp stays much warmer there than outside yet cooler than the house (non-heated). and not below freezing.

01/29/2010, 12:54 AM	#10
JimmyK Registered Member Join Date: Jul 2004 Location: Hillsboro, OR Posts: 80	I run mine off hot water tank cold side as stated above. Everyone pressure is different but you can always tap tank run line and test with presure gauge (assuming unit has one). I bet it would work for you. Someone correct if wrong but unless presure is horrible won't it just take longer to make ro/di?

01/31/2011, 06:11 PM	#12
cabanaboy1218 Registered Member Join Date: Jul 2008 Posts: 94	what if you run 30g hot water through it?

09/22/2020, 06:10 AM	#13
ramanbhalla Registered Member Join Date: Aug 2020 Posts: 3	If you're feeding the RO/DI unit from a cold water line, then it doesn't really matter where the source comes from. You could even put a tee between your toilet and its water source. As long as it's cold water. You cannot, however, feed an RO/DI system from a hot water line. Your thread title says that the water source for your RO/DI would come from your water heater. This will ruin the RO membrane in short order. As long as you source the water from the cold water input, the one that goes into the hot water heater, then that would be a fine option. check out the best portable water heater reviews to know what are the best water heaters available in the market.