side arm not working

[hickory hollow]

I have a side arm installed on my electric water heater that doesn't heat my water and I don't know why.

 

[DoubleB]

I'm not a boiler guy, but I suspect it has something to do with your hot water (red PEX) having to go downhill. Hot water wants to rise, and is unlikely to make the descent.

Reminds me of the discussion here:
https://www.hearth.com/talk/threads/thermosphion-backwards.141144/

 

[maple1]

It was working and stopped? Or you just installed and it won't work?

 

[Quincy]

Just a thought could you possibly have an air lock under the pressure relief valve .Thats preventing natural convection of the hot water maybe open it a bit to release the air, good luck hope it's an easy fix.

 

[Bioburner]

Pretty close to how I have mine but I installed the sidearm as low as I could to get as much thermal convection as possible. Dont worry about the pex going down hill as your using a pump. As Quincy stated try to crack the valve and it's very possible to have a airlock.

 

[DoubleB]

Guess I missed the pump but that sure makes sense.

 

[woodsmaster]

Ideally on the boiler side the hot should go in the top and out the bottom I believe, but don't think that would make it not work. open the relief valve and make sure you don't have an air lock. You should really have an air vent on the boiler and domestic side in my opinion. Maybe open the valve on the boiler side to to make sure it is circulating.

 

[woodsmaster]

Welcome to the forum.

 

[Karl_northwind]

the lower the better, and the less downhill from the top into the heater the better. I have seen these plumbed all sorts of different ways, and those are the key things I can tell you.

 

[hickory hollow]

thanks for all the info. I have opened the relief valve and have water coming out. I had this installed last year and its never worked at all. I had a plumber tell me I should install a pump to circulate the water in the water heater. but I have read a lot of people that don't have a pump and friends that don't have a pump either. its really frustrating!

 

[Quincy]

I just installed a new water heater as the old one rusted out I noticed on the 3/4 inch outlet of the new water heater there was a small plastic flap inside the nipple.I would guess some sort of check valve to keep hot water from naturally convecting out could that be an issue for you.

 

[cpeltier]

The hot from the boiler should come into the top of the shell for best performance but it will work if reversed. Are you sure that your boiler water is hotter then the contents of the hot water heater?
I've installed a bunch of these and the installation looks OK. As mentioned an air lock or check valve could be blocking the convection flow.

 

[velvetfoot]

I installed an auxiliary heat pump water heater into a relatively new electric water heater. A thing to watch for when installing is buildup of sediment on the floor of the tank that will block the flow of water through the drain valve. How old is the water heater?

 

[maple1]

I installed an auxiliary heat pump water heater into a relatively new electric water heater. A thing to watch for when installing is buildup of sediment on the floor of the tank that will block the flow of water through the drain valve. How old is the water heater?

That's a good point.

Also, measuring temps in & out of the sidearm on both sides of it might tell a tale. Sidearms work good when the boiler water is very hot, but no so much when it isn't. Mine was pretty well useless by the time supply got below 150 or so. The setup itself looks OK from the pics - I also think the hot supply is supposed to go in at the top as mentioned, but don't think that would make it not work, as also mentioned.

Re. the possible check at top of tank mentioned above - that looks like it's plumbed into the relief port, where there certainly shouldn't be a check.

Another little thing is that you will be losing heat off the uninsulated pipe before it hits the tank - may or may not be significant. I've got all my pipes insulated.

How exactly do you know it's 'not working'? Maybe it is heating some? But not enough for the demand? Might also measure temps at in/out of the mixing valve to make sure it's not mixing too much.

 

[hickory hollow]

That's a good point.

Also, measuring temps in & out of the sidearm on both sides of it might tell a tale. Sidearms work good when the boiler water is very hot, but no so much when it isn't. Mine was pretty well useless by the time supply got below 150 or so. The setup itself looks OK from the pics - I also think the hot supply is supposed to go in at the top as mentioned, but don't think that would make it not work, as also mentioned.

Re. the possible check at top of tank mentioned above - that looks like it's plumbed into the relief port, where there certainly shouldn't be a check.

Another little thing is that you will be losing heat off the uninsulated pipe before it hits the tank - may or may not be significant. I've got all my pipes insulated.

How exactly do you know it's 'not working'? Maybe it is heating some? But not enough for the demand? Might also measure temps at in/out of the mixing valve to make sure it's not mixing too much.

 

[hickory hollow]

I have my wood stove set at 170 degrees and I have water temps in the house around 165 degrees. I know the mixing valve is not the problem because I have checked the water straight out of the water heater and its only luke warm. the water heater is only a year old and there is a filter then a water softener before the water heater.

 

[perchin]

Hey there... could you please post a photo of the bottom of the side arm? It looks like your offset from coming straight out of the bottom... if your curve or 90° bend out of the bottom it simply will not work.

 

[hickory hollow]

there is 2 90 degree corners at the bottom one turns it and one to go up. I can take out the one that turns it but how can I not have one going up?
thanks!