Install electric tank

Thepred

Right now I have a boiler and a indirect tank. I would like to install an electric water heater for domestic hot water so I can shut my boiler off in the summer. Does anyone know if I can do this and have valves to switch back to indirect tank come winter when I turn boiler back on. Have looked every where for a plumbing diagram to do this. Any help would be appreciated.

icesailor

Water Tanks.

You already have a boiler, connected to an indirect water heater?

If so, and you want to purchase an electric water heater and connect it to the potable water system to try to save money, it can be done. I've never seen it work for anyone but it might work for you. I know it wouldn't work for me. Even with me doing all the labor and getting everything at whatever my professional cost is, I would never, ever get the cost back by any savings of doing the switch. In fact, the cost of just the electrical upgrade could be more than you can save.

Another good example of stepping over a $10.00 bill to pick up a dime.

heatpro02920

I have been doing this quite often lately...

With the rebates on hybrid water heaters available it can make sense... Plus with a hybrid water heater the bi-roduct is cold dehumidified air, so it can lower your cooling bill and or make you basement more comfortable... I have had customers tell me they no longer have to run dehumidifiers in the summer... Plus hybrids are very inexpensive to run...



I know the rebates we have here with the tax credits pay for 75% of the installation..



I will look for a drawing I have when I get back to my office and on a real computer...

heatpro02920

heres a similar drawing..

Like I said with the rebates on hybrids it can make sense, some of the benefits are..

annual savings, figure out you non heating month fuel usage and then subtract the amount it costs to run the hybrid unit.. if you use 30 gallons of oil a month in the non heating months that can be around $120 a hybrid can run for around $120 for the entire 6 month off season!!!

plus the above mentioned cold air benefits, less wear and tear on your heating equipment, ect.... It can be a good move...



the install is simple, run your power, tee into hot and cold with isolation valves, pipe out the condensate, and turn it on and the boiler off...

SWEI

How does the customer

deal with the stagnant water in the unused tank?

Thepred

reply

the #1 point of doing this is not to save money on oil. It is to not have fumes running into my backyard in the summer as well as the added heat the boiler creates in the summer months. Heatpro02920 in your diagram will have have to drain the water from the tank I am shutting off? Could I remove the indirect tank and replace it with some sort of electric tank, that would be able to heat buy electric in summer and boiler in winter?

heatpro02920

good point with the fumes, I didnt think of that for dv and pv systems...

I think there is a company that makes an electric aux indirect, others may know the model number?Swei as far as stagnant water goes, its not a huge issue, its only 5-6 months, no sunlight, under pressure kept cold, hot water not drinking, you can flush it drain it once a month or add a tiny bit of bleach if you like... I guess you could also drain it, but I would rather just keep it full...But in case you are worried I re designed it a bit, lolthis will make it so cold water flows through the tank not being used first then goes into the hot tank and onto the fixtures, no more stagnant issue, there are 5 different ways to pipe this, I would use some webstone purge tees and make it pretty simple, but you get the idea from my key and picture.. the thin lines that cross the pipes do not tap into the pipe they are crossing, and each number is a valve... just did it quick, you can do it a bunch of different ways... this drawing shows reverse flowing one tank but you can flow them both the correct way with the same amount of valves...

Thepred

On and Off

Does on me Open and Off mean closed?

heatpro02920

that would be the idea

Shouldnt be too hard to follow, when the valves are on the the water flows through them, I would simplify it and just shut the not in use tank off...

SWEI

clever

I like the concept.



Now can we build it so an ordinary customer can live with it?  The more I think about legionella the more I realize it's really a tough nut to crack.

heatpro02920

I would do this with colored valve handles..

So the valves that have to be open for the indirect to work would be Blue handled and there would be a blue label on the indirect, and the valves for the hybrid would have yellow handles with a yellow label on the hybrid..



The colored labels would say " to operate hybrid heater in summer months, open all yellow handle valves, shut boiler service switch and turn on hybrid tanks switch...



Now you could do this with a control and 6 electronic valves, but it would cost around $1000 just in materials, lol.. Much better option just to draw a diagram make some labels and trust the homeowner is smart enough to turn a valve {I know its asking a lot}... I honestly would probably take a picture of the valves in each position and have them printed and laminated then hung on each unit... even though its not hard to get, I feel some people may have trouble, lol....

Jean-David Beyer

trust the homeowner is smart enough to turn a valve

I know a married couple who do not even know how to operate an old round Honeywell thermostat. A simple on-off switch would work as well. They think the higher they set it, the faster it will heat their house, and the lower they set it, the faster it will cool down. They do not have a modulating boiler, and they do not have a proportional thermostat. Same for their air conditioners. I tried to get them to just leave it alone, but they think it saves energy to have the heat completely off during the day when they are at work, and on in the evening, and off at night. Well, if it gets really cold during the day, and their pipes freeze up (not likely, but not impossible here in New Jersey), fixing that will probably cost more than 12 hours a day saved on heating oil. For them, I would take the handles off the valves. But they would lose them, and that would annoy anyone who needed to operate them.



I have no idea what happens when they inherit my house with a mod-con with outdoor reset. The reset curve is set so tight that I maintain 69F. But when I turned up the thermostat up to 70F, it never made it because the reset did not deliver hot enough water to deliver it. They will probably replace the boiler because it is too small. Actually, it is about twice the size needed, but was the smallest one available at the time. (May 2009) I have a fancy programmable thermostat with 28 different temperature settings possible. I bought that when I thought it would save energy. But most of the house is radiant slab at grade, and unless I want to change the temperature for a week or more, I just leave it alone at constant temperature. I could put in a simple thermostat there but why bother?

SWEI

Three way ball valves

would simplify it.



The "cold tank preheat" could actually reduce required winter rise a bit.  Heck, you could run the heatpump just to get the water up to 60ºF and burn very little electricity.

heatpro02920

Thats funny you said that

I thought about 3 ways but then you still need an isolation valve on each tank since I 3 way is still on in one direction or the other... With the 6 valves you can use them to shut it down completely incase of service, with 3 ways you cant shut them off all together... plus 3 way ball valves are expensive, I pay $29 for one 3/4 3 way vs $30 for all 6 3/4 std ball valves...