Installing Hot Water Heater

[jeffesonm]

I recently calculated just how much money I am wasting heating my DHW with a tankless coil in an old oil boiler, so I pulled the trigger on a GE Geospring heat pump/electric hot water heater.

I plan to install this in series with the oil boiler, which I will shut down and turn on only when I'm away from the house for long periods in the winter. Otherwise I'll use my wood stove to heat the house and the Geospring for DHW all year round. Eventually I plan to add on a gasifier w/storage, and either keep the existing oil boiler as a backup or replace it with a different backup option. The Geospring will stay on to provide DHW in the summer time when the basement is warm and damp and I don't feel like making fires inside.

For now, it sounds like my best bet is to add water heater in series with the boiler by T-ing off the DHW line coming out, as depicted below. I'll install ball valves between the Ts and before the HWH so I can bypass if needed. I will then shut down the boiler (and hope it doesn't weep) and the water will just flow through the cold boiler on its way to the HWH. If I go away for several days in the winter, I'll just need to restart the boiler.

Does this sound like a good plan? Anything I'm missing? This will be my first plumbing job... excited to get some experience so I can eventually tackle a gasifier setup


Current setup


After HWH

 

[avc8130]

Why are you even bothering to keep the oil burner in the loop? What does it accomplish? Those coils are pretty much good at nothing and require frequent maintenance. Abandon the coil in the boiler in place and move on.

ac

 

[ewdudley]

Why are you even bothering to keep the oil burner in the loop? What does it accomplish? Those coils are pretty much good at nothing and require frequent maintenance. Abandon the coil in the boiler in place and move on.

ac

Agree there's no reason to route through the oil boiler.

However if the tankless coil is a good one it could be removed from the oil boiler and could be situated in the top of the new storage tank when that happens. Tankless coil in storage would be nice way to go for DHW.

 

[jeffesonm]

My thinking was that if I disconnect/abandon the coil in the boiler, I will need to do something with it otherwise the pressure will build up in it, correct? Hooked up in series would also allow for me to use the boiler for DHW (as it does now) in case something happens to the hot water heater.

What is the drawback? The coil could clog up or something?

 

[avc8130]

My thinking was that if I disconnect/abandon the coil in the boiler, I will need to do something with it otherwise the pressure will build up in it, correct? Hooked up in series would also allow for me to use the boiler for DHW (as it does now) in case something happens to the hot water heater.

What is the drawback? The coil could clog up or something?

You wouldn't get pressure because the DHW pipes would be connected to nothing and would be open.

There is no "advantage". The coils require cleaning and generally limit your DHW flow as they are 1/2". If the rest of your house is plumbed 3/4 you are giving up GPM of DHW.

ac

 

[jeffesonm]

Ok thanks. Here is the back of my boiler. If I understand this all correctly, I can close 1 and 2 and open 3 and 4. I can then tap into the cold water before the boiler, and the hot water running to the fixtures and I'll be all set.

 

[avc8130]

Whoa! How old is that thing?!?!?

What you propose sounds good.

By any chance, do you have an expansion tank on your DHW system?

ac

 

[Jmcqq37]

From what I can see, it seems your best bet is to cut in a tee in on the cold water before the makeup water for your boiler. Run this line to the inlet of the water heater. Then I would tye the outlet of the water heater into the outgoing of your domestic hot water.
I would put a check valve in the direct ionof flow off the boiler before you cut in the tee on the DHW to prevent it from going into the coil. Also a couple of ball valve on the inlet and outlet of the water heater will make swap out alloy easiler

 

[STIHLY DAN]

Do not go thru the boiler. It will sweat and rust out. Just grab the water lines at the ceiling. Also very good idea to put a mixing valve in this system. This will essentially make your 50 gal tank to an 80. You will be able to run on hp only longer.

 

[jeffesonm]

The water lines are easily accessible at the ceiling a few feet from the boiler, so I will tap in there. The boiler is a 1957 beast! There is an expansion tank you can see up between the floor joists but as best I can tell it is in no way connected to the DHW lines.



How does this look for a revised diagram?

 

[Jmcqq37]

Looks pretty good to me since your running off a well it might be considered a closed system. If that is the case if would be a good idea it install and expansion tank on the cold water. Maybe someone else can chime in. I'm not to familiar with a system feeding from a well. Let us know how the install goes

 

[maple1]

Shouldn't need an extra expansion tank - the regular well pressure tank should handle expansion too. As long as there's nothing (like a check valve) between the hot water heater & the pressure tank. And as long as the pressure tank is in good shape.

 

[STIHLY DAN]

You may want to put in some additional tee,s and ball valves for when you hook up your gassifier. Make it easer then, and no interruption of hot water.

 

[BoilerMan]

Maybe I'm not up on what you've tried with that old oil boiler...............but have you tried turning if off (like you were gone on vacation) for a few days. If it has essentially been hot since 1957 it may not fair well being turned off since it no longer needs to fire all summer for DHW. Most sectional cast iron boilers will seep water when allowed to cool. You may want to look into replacing it(if you want to keep oil), if for no other reason then to save some $$$$$$ on oil during the heating season. They don't make 'em like they used to, and in this case that is a good thing. A nice three pass oil fired boiler is much better than what is there (looks like an old Homart/Sears).

TS

 

[jeffesonm]

It is a 1957 Columbia boiler and came with a fat stack of service records dating back to its installation, including a new burner a few years back.... works great, just wastes money staying warm for the small amount of hot water I need.

I did read about the potential for weeping... only thing I can do is turn it off and hope for the best. I plan to heat exclusively with wood and then with the electric water heater, so I'll only need the boiler on if I go away for a few days in the winter. Either way I will probably keep an eye on CL for a good deal on a newer boiler... lots of folks upgrading to natural gas around here so I should be able to find a good deal.

 

[avc8130]

Where are you located? I have a nice oil boiler I pulled out to install my wood boiler. If you are near NJ let's make a deal.

ac

 

[jeffesonm]

I got the water heater installed last weekend and everything is working as expected. Just one leak... a stupid threaded fitting I think I messed up when I backed it off a bit to line up the mixing valve.



Also pleased to see the oil furnace does not appear to be leaking at all. It's been cold for a week now and no puddles. Now the gasifier reading/planning continues......

 

[chuck172]

You should have unions below the shut-off valves.
I too have a geospring. Love it, best improvement I've made to my heating system.
I now use my superstor as a tempering/pre-heat tank, and feed my Geospring through it. Gives me a total of 90 gallons of super-insulated domestic hot water. I used to burn my Tarm all year. What a wasted of time and firewood. The Geospring is a God-send!