The hot water storage tank is leaking. Time to replace it. I have several (stupid) questions.

If it is just a storage tank, why are my purchase choices between gas and electric? I don't see where the present tank is wired into anything...

We have an oil fired boiler. Is there any reason we can't eliminate the tank and have a mixing valve installed and just let the heat exchanger on the boiler supply the domestic hot water?

Finally, (a little knowledge is a dangerous thing) I am reading that storing the water at 120* is not enough to kill bacteria. What should we be doing?

Water heaters aren't expected to kill bacteria and anything over 120 can hurt folks. So you have what we call a combi boiler, right. Heats your home and makes potable hot water. If you are looking at units that are gas or electric you are looking at the wrong equipment, those are water heaters for folks without a combi.

'Combi' is a new word to me. We have a burnham boiler with a hot water storage tank. My understanding is that the boiler heats the house via HWBB and there is a circulating pump that maintains the temperature of the stored hot water in the tank.

Is it possible that this think is an "expansion tank"?

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If it is just a storage tank, why are my purchase choices between gas and electric? I don't see where the present tank is wired into anything...

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This brings up the question, Who gave you the choices? Bob's correct you should be looking at storage tanks.

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Finally, (a little knowledge is a dangerous thing) I am reading that storing the water at 120* is not enough to kill bacteria

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Question: Does Hot Water Kill Bacteria?

I get emails at least once a week from those who are skeptical about the need to use hot water to kill bacteria. Some people want to save a little money and use cold water for dishwashing and laundry. Others feel that soap is enough to get rid of bacteria. They all want to know if hot water really kills bacteria.
Answer: For bacteria to actually die, the hot water would have to be at a temperature above what your skin could tolerate. Most people can tolerate a temperature of 110 degrees for little bits of time, but that's the most we can do. To kill bacteria with hot water alone is not feasible when you are handwashing items.

However, hot water, is necessary to get rid of bacteria. Hot water and detergent together attack oils and grime. That oil and grime that you rinse away with the water contains bacteria. Without hot water, detergent is unable to be as effective. You may end up with an oily residue on your dishes or clothes.

Hot water also makes dishes able to air dry on their own very quickly. You can do your own experiment to watch this in action. Take two dinner plates. Rinse one in cool or even warm water. Rinse the other in very hot water. Set the plates down and watch them dry. You'll be able to see the hot water plate dry right before your eyes.

But why do we care about dishes drying quickly? Wet dishes and dishcloths are a haven for bacteria growth. Dishes that dry on their own, don't have to be towel dried, risking cross contamination. If your dishes are completely dry in your cabinets, you give no opportunity for them to be contaminated.

So technically, hot water by itself can kill bacteria, although it would have to be hotter than what we could tolerate. But the hot water we use is necessary to remove bacteria from our surfaces.

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We have an oil fired boiler. Is there any reason we can't eliminate the tank and have a mixing valve installed and just let the heat exchanger on the boiler supply the domestic hot water?

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No reasoin at all if you enjoy cold showers. When hot water's produced you must have a place to store it, Otherwise you'll run out of hot water in short order. You can't treat your combi boiler like a "on demand hot water heater" It just doesn't work that way. Regards, tom

Combi just refers to the fact that this is a combination home heating boiler and a supply of domestric hot water. Contact these folks and see what they recommend.
Burnham Boilers & Water Heaters

Wow... thanks for the education. No, this is a storage tank. The expansion tank is above the boiler.

The plumber with whom I have made an appointment knows what I have but told me I could save money if I 'bought the tank myself, buy a storage tank with elements'. He can't get here for two weeks (!) and I don't think this thing will last that long. I have calls in to other plumbers, but really have no idea what I am doing, hence the questions. Finding an available plumber in Alaska is not an easy task.

Our last home had the same type boiler and we had no storage tank. I know what 150* water does to skin, so I figured there must be some other option to the storage tank.

Yep Tom and I do not make house calls to Alaska so I understand the dilema. Buying a tank with elements and then not using them seems wasteful. Try googling heating and HVAC companies in Alaska.

Hi Peanut...

It could be a combi. Boiler.. OR it could be a tankless coil..? How old is the bolier unit Peanut?

Sounds to me like you have a boiler with a TANKLESS COIL. With your old boiler you didn't have a storage tank because you don't necessarily need to have them with this system. Here, a MIXING VALVE (see image) is used to temper the hot water from 150ish F at the tankless coil to a 120 F and then hot water is delivered to the house...

The big problem with theses systems is that the tankless coil has a tendency to clog up over time and can reduce the hot water available to the home significantly enough that almost everyone ends up installing a storage tank like you have now.

In terms of hot water availability to the dishwasher some manufacturers recommend that you send a dedicated 140F hot water line to the dishwasher and reduce the rest of the hot water to 120F usung the mixing valve I mentioned... this is ideal, but unfortunately a little unrealistic as most people simply don't want to pay the plumber to run a dedicated line.

Fact is, that 120F is usually fine... I mean, you don't hear of people getting sick too often, right?? ;)

Anyway, just wanted you to know more... let me know if I am wrong on the tankless coil. If I am... tell us the name on the storage tank you have now... shouldn't need an electric type water heater for storage tank..?

MARK

This boiler is old, #V18AT, and I tried to send a photo, but the site wouldn't accept it. You are right, the boiler in the other house had coils that got clogged and we had to replace the coils after living there for ten years. (So about the life of a hot water heater).

I appreciate your time. I just don't want to make a plumbing mistake. The guys up here will sell you all kinds of things...

Yes, it makes no sense to me to buy a 'storage tank with elements' if the elements don't get used. I'm looking in plumbing supply for storage tanks and coming up with nothing. I have an inquiry in to Burnnham, but I suspect that the age of the boiler dictates replacing the tank and not trying any fancy stuff...

Pics gan be posted with go advanced/manage attachments. Photos may have to be rezised with the free program IrfanView - Official Homepage - one of the most popular viewers worldwide. Make the largest dimension 640 pixels and go from there.

Okay! Actually had a fellow come out here who is familiar not only with the system, but the house too. He said he worked on the place fifteen years ago. I tried to tell him on the phone that there was no circulating pump or electricity to the hot water storage tank. He didn't believe me until he saw it. He says that the coil is definitely clogged and says that replacing that and hooking up a thermostatic mixing valve to the domestic water is what he would do, eliminating the storage tank altogether. I asked if that would be enough hot water. He said the V1 is capable of producing (with a good coil) three gallons per minute. Based on everything I have crammed into my head this morning, this sounds like the right thing to do. The only hitch at this point is the fact that there is not a coil in town, but that can be solved easily enough. We do get planes here.

Sound like a feasible solution to you guys? I'm still worried about that cold shower prospect!

Sounds like a plan but 3 gallons per minute is on the low side. How many folks in your household? I do not work on they but thought a boiler coil would produce a lot more hot water.

Just two in the house, unless you count pets. I thought three was low too, but have to remember that it is coming straight out of a boiler that is often operating at 200*, (hence the thermostatic mixing valve).

Lets wait a bit until one of the regular plumbers on the desk can see this. I installed a tankless system rated for 7.4 gpm, this is an instant heater. Most of the guys said I was undersizing but we have up to 6-8 folks visiting on weekends.

Again, thanks loads for this conversation. The only thing more frightening than plumbing is electricity!

The plumber just called and said he found a coil and is good to go for the described installation first thing in the morning. I have enough towels to last until then but I guess I'd better tell you the rest of the story before the regular plumbers on the desk look at this convoluted tale.

The 'maintenance room' has a lot of stuff in it, some that is old and unused (the house used to have an indoor pool) and so the area where the tank is is very tight... too tight for that tank to come out in one piece. Plan is to drain and detach it, then let it dry out and take a sawsall to it, (a homecoming chore for my unsuspecting husband). Aside from the debris buildup that is in the bottom, will there be any surprises (i.e.. Asbestos) in that storage tank?

Must say at this point that building code is not much of an issue in most of Alaska... you make things work however you can, and this old house is Alaskana at it's best!

Hi all:

First step is usually to do an acid wash of the coil... see if you can loosen the deposits and restore original coil. Done with an acid solution and a recirculating setup/pump. Your boiler/coil sounds too old for this solution (but never hurts to mention it to the plumber... see what he thinks).

Second step is to install a new coil. You can install storage tank or not.

If you choose to install the coil without the storage tank be aware that 3 G.P.M. is reasonable for two people... but it will not usually work well for... say... a family of 3 or more. In this case, you would definitely want to install a WATTS P3 valve into the cold water feed into the tankless... reduces the rate of flow without reducing the volume of water available... a major factor in maximizing tankless coil output. It should be set at 3.5 G.P.M. to start... see info. Below. Check it out at:

http://www.watts.com/pro/_productsFu...pid=3425&ref=1

See what your plumber thinks here.

Otherwise, may be a good idea to consider storage tank/recirculating lines. Again, discuss with your plumber.

At a minimum, try without the storage tank, but have the plumber pipe it all up so it is easy to install a new tank if needed in the future... ;)

Finally, in terms of removal of the old unit, there should not be any great surprises... just that the bottom 1/2 will have sediment and it will be mucky/yucky so you want to plan to lift straight up to remove. Hopefully, the plumber can figure some way to remove it with less work... *crossing fingers*.

Just my thoughts...

MARK

Once again, I can't thank you guys enough. I have learned way more today than I really wanted to... baking would probably have been more relaxing. I'll talk to my plumber first thing in the AM about the Watts P3 Valve... how exciting to read something and actually understand! You bring up a lot of good points that I just don't think about in my flustered condition. I'll let you know how it all turns out. I have made copious notes for tomorrows operation. I bet plumbers just love homeowners like me...


Final report: The storage tank has been drained and disconnected. My plumber estimates the age of my boiler to be nearly 20 years. It had in it's original coil! As you can imagine, an acid flush was just not an option. He installed the new coil, it provides five gallons a minute, and a mixing valve. Mark, because we don't let the temp of the boiler drop below 120*, (this is Alaska... ) he said a Watts P3 valve is just not something he ever has occasion to use. Now, about the amount of hot water. Wow! I washed all the towels I had used to soak up the flood, and there was steam coming out of my washer. The water in this house has never been this hot. (And the mixing valve is set at 120*). I guess we have had issues from the beginning and just never realized. There is no running out either. It just keeps making more.

A final thanks for everybody's input. I knew what kind of questions to ask and I feel like the job has been done as close to what resembles code as we have here in Alaska. I certainly learned a lot. Wonder if I will ever use that knowledge again?

Thanks for the update... ;)

The temp. of the boiler has nothing to do with volume/flow of water through the coil, so plumber didn't understand the funnction of this valve. If you find you start to run out of hot water or have to start adjusting your shower periodically you may need to reconsider the P3 valve.

He did install a mixing valve.. correct? Typical boiler runs at 190F in my area, so be sure to adjust the mixing valve if you adjust the boiler temps. In any way!

For now, it sounds like you are fine! Good news!

MARK