What to do?

Unknown

I have a Weil Mclain P-366 HEboiler. At one time it was used to heat the domestic hot water but that service was disconnected (before we purhcased the home 12 years ago).  3 questions.  If there was a problem with the tankless system why would they have replaced the service with and electric hot water heater? How easy/difficult would it be to replace the old coil and switch the system back to oil?  With current cost of oil, would I end up paying more for hot water in long run if I switch back to oil hot water?

lchmb

better option

If you were to add the coil back into the boiler, you would then need to maintain temperature on the boiler which would increase your fuel usage. A better option would be to add another zone to the boiler and add a indirect. I would also suggest you start considering replacing the boiler as it is an older system. Have a heat loss done for your home and get a 3 pass oil boiler in there and start saving money...

Unknown

Is it worth it?

Would I get better efficiency with a new system?  I am  currently getting 80-83% with my current system.

lchmb

pin style

Like I said, I would start with going with an indirect. After that the options are open. Keep in mind your system is roughly 20 years old. At some point it needs to be replaced prior to failure. I can speak from personal experience in that I swapped my Father's coil out from a similiar model (p368). I removed the coil, and added an indirect. This alone cut usage approximately 15%. Due to the age of the system we left if set to a low temp of 140 degrees. Next year I intend to replace the boiler with 3 pass design. The reason I recommend replacing the system, at some point due to age it may/probably will fail. If you do it now, have a properly sized system installed with a  heat loss, you can save yourself money and headaches. If you wait for it to go, it will be the coldest day of the year and you will get a cut and paste emergency install that will get you heat, but it wont get you everything you should have. If of course someone is free to help you the day it goes...

You could look at the System 2000. Low mass high efficiency...

lchmb

one other thing

I like the way the view door is wedged into place with copper. Is this due to back pressure or rattling?  I'm guessing back pressure since it was cemented shut. This tell's me the passage's are not properly cleaned and the system not set up since it should have a negative -.01 over fire...Also, your electronic's are original and at some point will start to fail. Pay once or pay many times...

Steamhead

Hard to tell

what burner is on that boiler- can you elaborate?



The old 45-CU burners were real sootmakers, but those 66-series boilers run fine with Beckett AFG units.



Not sure you'd be any better off with a newer pin-type boiler- I'll second the recommendation for a 3-pass.

billtwocase

Frank

It looks like a Blue Angel with some kind of OEM color? I would agree with an upgraded boiler. Worse than a 68 series was the 66 in my eyes. If there is no replacement in this things future, I would put a blank plate in place of that leaky coil to start with,and an indirect would depend on a heat loss to see what this boiler is already trying to do. It was a poor install to begin with, and chances are the top of the boiler was air-bound during the summer months. That extra tapping was put there for auto air eliminator. Possible problem in hot water production also.

icesailor

What to do?

A word from the heretic

If the long green (or lack of), is a serious consideration, connect the gas water heater to the tankless coil and make the water heater a storage tank. The P66 boiler is better than a P66 but not better than a WTGO. A water heater connected to a tankless is an indirect. It's just that the coil is in the boiler and not in the water heater. You don't need to add a zone. Some here are crazy about cold start oil boilers with indirects. They must not have to clean them. I do. Sometimes, even a soot saw won't get the kibbles and bits out. The burner bites. A Carlin EZ-1 would better than an AFG in my opinion. That spacer on the opening shows that there are draft problems. These boilers are notorious for rumbling. That is what that round thing below the burner on the chamber cover is for. You are supposed to fix it by opening the cover. Not wedge the view port open.

The suggestions for a new boiler are fine if you have the cash to do so.

The non heretics hate pin type boilers. You have a pin type boiler. Non heretics love triple pass boilers. They have long, smooth passageways. Very little turbulence. Pin types have short passageways with pins sticking out in the way causing lots of restriction, resistance and slower flue gases for the length of the passages. The big old boilers I installed many years ago all had long smooth passages. I used to put bricks in the passageways to add restriction.

So if you want to replace it, everyone will suggest a triple pass oil boiler.

Most everyone seems to go gas.

If it were mine, and I didn't have a lot of money but want to save a lot on fuel cost, I'd connect the tankless to the existing water heater. And that's what I often do if cash is an issue.

 

Steamhead

I've had less hassle

with 66 units than 68s. The 68 flueways are tighter than those of the 66, and even an AFG can be finicky in a 68. If I had to re-burner a 68 instead of replacing it, I'd use an NX, CF375 or Riello. Not sure if the EZ series can produce as much static pressure.



If that is a Blue Angel, it should be fine in that 66 since it can produce a higher static pressure than the Beckett AF or Wayne MS-R, both of which can do better than the 45-CU. But like anything else, it has to be set up properly.

Steamhead

But a gas water heater

has a flue pipe running thru it, which will draft cold air and the tank will cool down faster, wasting fuel. This is not a problem with an electric tank-type heater. 

billtwocase

66 series

Although they were a little easier to clean, they had little to no chamber area. That's why they were rather rumbly as Ice man speaketh. I will agree on not a god idea to turn the gas water heater into an aquabank. 1 being the potential heat loss, and 2 how would you adapt an aquastat to it? Do the have 1/2" or 3/4" tapping in the tank for a contro well? I don't do gas, so that may sound like a dumb question. Guess I'm just a stupid, cheap, lazy oil guy, and a knuckle dragger at that.

lchmb

guessing

In the case of a gas water heater used for a storage tank, you could remove the gas valve and add a well, but why would you? If your going to spend that much time and money your just as well off with an indirect with less stand by loss....On top of, it can then be adapted to any system that replaces this one down the road, whether gas or oil.....Pin or 3 pass.....no coil needed....

icesailor

What to do?

Some guys would disconnect the flue pipe and put a cap over the top of the water heater.

If I was short in the cash, I'd go with the water heater, electric or gas.

icesailor

Storage Tanks:

In case no one ever noticed, the first "Aqua Banks" were gas water heater tanks. That's why they used a stupid piping set-up and ran one of the water lines to or from the tankless through the 3/4" tapping where the gas valve goes.

If you leave the gas water heater domestic piping in place, you only need to swap the drain for a tee and a circulator pumping back to the tankless. The outlet to the tankless goes into the cold inlet of the water heater. You can use that cheap POS control that comes with all the indirects.

If you give someone a price that is >$*000 and it is way more than someone is willing to spend, and someone else gives them a price way

lchmb

dont take this wrong

But I would rather give them a higher price and have them opt to go to the low bid over dropping down to be the cheap guy.

Robert_25

Reminds me of my basement

When I moved into my house one of my first tasks was servicing the boiler.  A 6 section 66 Series Weil McLAIN with a 45-CU burner.  That thing was so plugged with soot I could hardly saw it out of there.  Despite my best efforts, I could never get a clean burn out of that thing.  Higher fuel pressures, different nozzles, etc etc....it still took a LOT of excess air to get down to No. 1 smoke.  I finally got fed up and swapped in a Riello burner.  That was the end of the soot and smoke! 



To the OP - If changing the boiler isn't in a the budget, a new burner and controls should extend the useful life of it. The tankless coil can be used to circulate through an electric hot water heater as suggested, but you will need to make sure the existing tankless coil isn't plugged with calcium or sediment. 

deathray

View door

The view door is wedged with a piece a copper to kep it from falling off.  The swinge hinge broke and that's what I came up with to keep in place.

deathray

Water heater

I do not have my a gas water heater, it's electric.  That was my original question.  Should I leave things alone and keep the electric or would be worth my while ($$) to replace the coil and reconnect the hot water back to the boiler. 

As for the boiler itself, she runs pretty good. I get it serviced every year and runs clean from what I can tell.  Never have black smoke coming out of the chimey like some of my neighbors.  The service guy did recommend replacing the combustion chamber.  I just bought a Lynn kit which I plan to replace myself in a couple weeks.

deathray

Why circulate through the electric?

If the coil acts as a tankless system hy would there be a need to circulate through the electric tank?

Jean-David Beyer

As usual, it depends.

Back when I had an oil burner and an electric hot water heater, I changed it around. The boiler had an unused hot water heating coil. The houses around here were designed to use the coil for hot water. The former owner did not like that and installed an electric hot water heater in the 1950s when the power company gave a big discount for hot water heaters. There were two meters, one for the house and one for the hot water. The heater meter had a clock in it that shut it off from 4PM until 11 PM because that was when the peak load was in those non air-conditioned times.



By the time I got the house, the rate for the hot water heater was almost the same as the rate for the rest of the house. So I ran the cold water through the coil to take the chill off the water before it went into the electric heater. The boiler ran between 130F and 140F, so it would not have been quite hot enough, I suppose. I had three gate valves so if the coil leaked, I could shut it off and everything would continue to work. That way, the oil heated the water up and the electricity just kept it warm -- sort-of. Oil prices in those days were a lot cheaper than electricity. Of course, I did not use oil to heat domestic hot water in the non-heating season.



When I got a mod-con, I also got an indirect fired hot water heater, and that ends up being cheaper than the old way. The mod-con is gas and runs cold start, so I am not keeping the boiler water hot all the time. And around here the gas rates continue to drop. They currently charge $1.2734 per therm (gas and delivery) and $8.25 customer charge.  I used about 100 therms in February for house heating and hot water.

Robert_25

it depends on the cost of each "fuel"

What do you currently pay for fuel and electric? No. 2 heating oil is around $3.55 in my area, electicity is about 12.5 cents per kWh. With those prices, and the standby losses of my old oil boiler, it would be cheaper to make DHW with an electric water heater.

deathraay

3 pass?

A couple of folks have mentioned replacing my system with a 3 pass.  What is/does 3 pass mean/do?

Steamhead

In a 3-pass boiler

the hot flue gases travel to the rear of the combustion area, then rise and come to the front of the boiler, then reverse, travel to the rear of the boiler then out to the chimney. So they travel the length of the boiler three times, giving off more of their heat.



One big advantage of a 3-pass is that if they get dirty, you can clean pretty much everything by opening one big door in the front. This makes them much easier to maintain.



Older designs like the 66 series have several vertical flueways from the firing zone to the flue collector. Each flueway has a maze of pins sticking into it that absorb the heat. This type is more difficult to clean properly, and may lose efficiency over time.



Some 3-pass boilers are the Buderus, Burnham MPO, Biasi, Slant/Fin Eutectic, Solaia, Weil-McLain Ultra Oil etc. Some of these are approved with gas burners as well as oil burners.

deathraay

Will gain efficiencies?

If I replace my old 66 with a 3 pass will I gain efficiencies?  Right now I get about 80-83%.  I know the system is old and rusty but it does a fine job for our small home (1300 sqr ft).  I just bough a combustion chamber kit which I will be working on the next few weeks.

Robert_25

Might make more sense to tighten the envelope first

How fuel do you burn per year? Is the home well insulated and tight?

deathraay

Not too much.

Last year I had 372 gallons delivered.  Let's say I use 400 gallons.  My home is not well insulated.  Plaster walls on firing strips on block, outside is stucco and a flat roof that's also not well insulated.  Not much I can do to increase insulation unless I spend to have the stucco redone with Styrofoam underneath.

Robert_25

400 gallons is pretty light

400 gallons per year...even if you saved %25 with a new boiler it would take a long time to recover the cost.  I would consider updating the controls, possibly the burner, and install an air vent in that tapping next to the supply riser.