Max height above the tank for a side arm?

[troy3300]

What is the maximum height above the tank a side arm HX can be plumbed? My problem is my water heater has four access points. 1-the cold water in port, 2-the temp and pressure relief, 3-the hot water out port and 4-the drain. I know the drain port gets hooked to the bottom of the side arm. I really don't want to mess with the t&p valve since some people say it is fine to tee it off and others say never mess with it. So that leaves the the hot out port. If I tee it off then the plumbing is going to be between 4-5 inches higher then the tank. Would that still be OK?
Thanks for the help
Troy

 

[Mister Twister]

I heard you are not supposed to go more then 4" above the heater or the thermosiphon effect will work or convection what ever you call it. I put a tee in my t&P valve it will not effect it at all unless you block the port off to it somehow. Mine works great.....

 

[i'mstihlaguy]

I heard you are not supposed to go more then 4" above the heater or the thermosiphon effect will work or convection what ever you call it. I put a tee in my t&P valve it will not effect it at all unless you block the port off to it somehow. Mine works great.....

+1

Here's a scan from my manual. There is a note under the view that says to keep bottom loop (and side arm) as low as possible. You may also need a way to bleed air if you run up over the top of the water heater. What's wrong with putting a T at the T&P?

 

[Hawken]

Keep it as tight to the top as you can. Hot water will rise if it has to be forced back down into the tank. If the pressure pushing up is greater than the force pushing down you will not get the thermal action, so no hot water. My top pipe went in where the anode rode was. I have 50 gallons of 160 degree water waiting to be used. I have been electricity free for hot water for almost 4 weeks now.

If you have other problems see if you can find a tank from someone. Just use the tank in the winter when you fire up your OWB and use the water heater in summer.

 

[troy3300]

+1

Here's a scan from my manual. There is a note under the view that says to keep bottom loop (and side arm) as low as possible. You may also need a way to bleed air if you run up over the top of the water heater. What's wrong with putting a T at the T&P?

Not sure why some people say not to move the t&p valve.
The pic helps alot. Thanks

 

[i'mstihlaguy]

Not sure why some people say not to move the t&p valve.
The pic helps alot. Thanks

You are welcome. I had originally planned to install a BPE (brazed plate exchanger) but I'm going with a side arm instead since my hot water consumption isn't all that much.

 

[blakey]

The top of my sidearm is actually quite high ( almost level with the bottom of the floor joists above) and I'm sure my instructions from CB indicated that at the time. It has been working great for 7 years, we have never run out of hot water.

 

[i'mstihlaguy]

The top of my sidearm is actually quite high ( almost level with the bottom of the floor joists above) and I'm sure my instructions from CB indicated that at the time. It has been working great for 7 years, we have never run out of hot water.

Why would you purposely run it that high. Not criticizing, just curious.:monkey:

 

[blakey]

The kit I got from the CB dealer was for a 60 gal water heater (which I have) so I used the whole length of 1 1/2" copper they included for the outer shell of the sidearm. I figured I might as well use it all to get max heat transfer. I could have cut a couple inches off the inner 3/4" pipe but that's about it. The top is 18" above the top of the water heater. I guess my point in posting was that it works great. This was 7 yrs ago and I had never heard of or seen a sidearm before. Took me a bit to wrap my head around how it worked, I show it to people and they don't get it. My dealer installed one at his new house and the building inspector didn't get it, he thought for sure the domestic hot water was mixing with the boiler water.

 

[i'mstihlaguy]

The kit I got from the CB dealer was for a 60 gal water heater (which I have) so I used the whole length of 1 1/2" copper they included for the outer shell of the sidearm. I figured I might as well use it all to get max heat transfer. I could have cut a couple inches off the inner 3/4" pipe but that's about it. The top is 18" above the top of the water heater. I guess my point in posting was that it works great. This was 7 yrs ago and I had never heard of or seen a sidearm before. Took me a bit to wrap my head around how it worked, I show it to people and they don't get it. My dealer installed one at his new house and the building inspector didn't get it, he thought for sure the domestic hot water was mixing with the boiler water.

Got it. I don't know if I will make mine or just buy one.

 

[Slick]

Got it. I don't know if I will make mine or just buy one.

I just pondered the same situation last week....if you have a hook-up for 1.5 or 2" copper pipe it might be worth making one but if you have to buy it...works out better to buy it pre-built. the large pipe and the top large fittings kill the budget...

 

[Hawken]

I bought one of those stainless side pipes that have the fins on the inside and 3/4 threaded ends. My brother-in-law has a plain copper side pipe with 3/4 ends. They were both around $190. I had some trouble at first getting the stainless not to leak because the threads were so sharp they would cut into the brass fittings. After tearing it apart 5 times I got it figured out. My Brother-in-law just used sharkbite fittings and it went together easy. Those things are slick. Hope they don't leak a few years down the road.

 

[blakey]

I should have bought a few more kits back then, I think it was only $80. The price of copper went up shortly after that.

 

[troy3300]

Mine is four foot long copper with a 1 1/2 inch outer pipe and the standard 3/4 inner pipe. It was $145 total. It just needed to be sweated together. I also put insulation around it to keep the maximum heat in.

I hooked it up just like the diagram i'msthilaguy posted. It seems to be working good but I will let everyone know when I get my next electric bill

 

[i'mstihlaguy]

I picked up my side arm today. I guess mine will have to run above the tank as well cause its pretty long. After its installed, I plan to turn off the power to the HW heater and see if I ever run out of hot water. I guess a mixing valve is a must with a side arm because the water in the tank can get way hotter than you need.

 

[oneoldbanjo]

On my water heater I used the T&P port that is located on the side of the water heater - I just removed the T&P valve and installed a short brass nipple and a Tee. I think this works fine as the hottest water will be at the top of the sidearm and the pressure will be the same.

By going in the side the height of the sidearm is reduce a bit, and I wanted to use all the 4 feet of pipe....so I put a 90 degree elbow in both the 1" inner pipe and the 2" outer pipe. When brazing it together you have to be a bit creative and braze the inner 1" elbow first while the 2" elbow is slipped over the 1" pipe, and then follow with brazing the 2" pipe. I have about 12" of the sidearm running horizontally just below the water heater and then it turns and rises and goes up to the side of the water heater where the T&P valve was. My water heater is mounted on a wooden platform about a foot high to allow the clearance. I also have the fill point for the OWB plumbed into the bottom of the sidearm so that all the air is bled out of the system while filling the OWB - my sidearm is the lowest point in my OWB system.

I am out of town this week and will post pictures when I return.

 

[troy3300]

I picked up my side arm today. I guess mine will have to run above the tank as well cause its pretty long. After its installed, I plan to turn off the power to the HW heater and see if I ever run out of hot water. I guess a mixing valve is a must with a side arm because the water in the tank can get way hotter than you need.

I thought about turning off the power to the water heater but my wife takes her shower first in the morning and then I do shortly after. I am doubtful the sidearm would keep up since she likes super hot showers ( she comes out red) and I hate cold showers. I have turned down the temperature settings on it. I thought about a plate style but after pulling off the drain valve I am glad I went with the sidearm. I would have plugged a plate style.

I know i will hear form some people about this but I did not install a mixing valve. My youngest is 13 and there are not any elderly living here ( the way I feel doesn't count) and before the sidearm, my water heater settings were maxed out. Like I said earlier we have short times every day of high demand and we/I needed it maxed so I didn't have to take a cold shower after my wife. We are use to being careful with the water. If you have young kids or are not use to having very hot water a mixing valve would be a must.

 

[oneoldbanjo]

I don't have a mixing valve on my water heater and OWB setup, and it works fine. We don't have any small children and we warn guests. It has never caused a problem in our house - but we don't have the kind of pumbing that scalds people in the shower when you flush the toilet. With care I think it works fine and we have never considered a mixing valve a necessity.

 

[i'mstihlaguy]

Oneoldbanjo - Can't wait to see pictures of your side arm or anyone else's for that matter.

 

[oneoldbanjo]

Sidearm photos

Well here is a picture of my sidearm.....an unusual installation by most standards but it works great. I did this unusual approach based on three things that I thought was important. 1) My water heater is not very tall and I did not want to shorten the length of the sidearm and I wanted to use the entire length of pipe that came with the kit. 2) Even though the manufacturer says it is OK to have some rise above the water heater I did not want to do that as I believe it will have some affect on the efficiency. 3) I wanted the fill point for my boiler to be the lowest point in the system so that air will be purged during the boiler fill process. The black insulation keeps too much heat from escaping and prior to it being insulated it would make my house too warm on some days - there is a lot of heat that comes off the sidearm if it is not insulated. The insulation is the kind that is split and has the adhesive on the cut portions - the 1" size works great on the PEX tubing and I belive I use a 1" and 3/4" size stuck together to cover the 2" pipe on the sidearm.

This is the water heater and sidearm. The water heater is mounted up on a platform that allows the cold water to drop out of the bottom of the tank and into the sidearm. I cut the 1" interior pipe and 2" outer copper pipes and purchased 90 fittings and made a 90 degree angle in my sidearm. The hot water from the OWB flows in the pex tubing that enter the top right side of the sidearm in this picture and it flow back to the furnace after leaving the sidearm at the bottom.

This is the T&P valve on my water heater. I removed the valve and bought a short brass nipple and a brass tee to move the T&P valve out. The hot water from the sidearm enters the bottom of the nipple and flows into the water heater. Since this is the hottest water in the system and it is passing right through the T&P valve I believe the system is operating as it should.

This picture shows the pipe from the bottom of the water heater on the top left that goes from the water heater drain hole down to the sidearm and the valve with the silver knob that is installed to drain the water heater. The valve with the green handle makes it possible to shut the flow in the sidearm off - which I do when I go away and don't want heat from the OWB heating water. The 1" copper pipe then flows sideways and enters the 2" pipe and goes for about a foot and makes a 90 vertical turn inside the 2" pipe. The 1" pipe for the OWB drops out the bottom and goes to the heat exchanger in the furnace. The 1/2 inch pipe with the yellow handled valve is my filling and drain point for my OWB - it has a hose connection and I take off the cap and connect a garden hose to my utility sink in my basement when it is time to fill the OWB.

This last picture is the Compunurse temperature monitor that I have installed in my basement. This is made for monitoring computer hard drive temperatures and reads in celsius. It has a tiny temperature sender about 1/8 inch square. I just put the sender in between my PEX tubing and the insulation. For my system it reads 60 degrees when the OWB shuts the blower off at the high temperature, it reads 50 degrees when the blower turns back on, and it reads 40 when the OWB thinks the fire is out and shuts the blower off. When it is between 50-60 I know the fire is good and I don't have to go outside. When it drops below 50 I know it is time to tend the fire. They cost about $ 24 and you can find them online at computer stores by searching compunurse.