weil mclain boiler with boilermate vs toyotomi om-180

There are so many possible combinations of heating, I couldn't really find my combination so I decided to start a new thread. here is the deal: I have a weil mclain 100,000 btu boiler with three zones set up. one for the upstairs, one for the down stairs, and one for the 41 gallon boilermate. All of this is located centrally downstairs and the main living area is upstairs. the house is about 2800 square feet with half upstairs and half downstairs. I also have a wood stove downstairs. without the wood stove burning, I hear the boiler kick on and off constantly all day. With the wood stove burning the house stays well above the kick on temperature for the boiler, but I assume it is trying to keep that 41 gallons of water in the boilermate warm. if I leave the boilermate turned off, I never hear the boiler turn on, and the internal boiler temp drops big time. my first thought was to get rid of the boilermate and put in a toyotomi 0m-148 for my domestic hotwater supply, but then I thought maybe I should get rid of the whole setup and just get a om-180 to act as a hydronic heater as well as for my DHW. I am wondering if the toyo can keep up with my heating needs. does anyone have any thoughts on any of this?

Thanks for any and all info!

If the Toyo is one of those gas instant water heaters they have a very good efficiency, when they are new. I have seen test reports that show this drops off after a bit of use as the exchanger coats with mineral & impurities in the water. I'd lean toward a high quality condensing boiler, or modern Lambda wood boiler, Randy

If your boiler is set up to start at a minimum temp it will periodically cycle just for that. If it set up for cold start it would just go completely cold if never calling for heat. If turning off the boilermate stops your boiler from cycling and no hot water was used, then your boilermate is losing heat somehow. Either a hot water leak someplace or it has really bad insulation. The cheapest place to start would be to insulate your boilermate with an insulating jacket and possibly the pipes to it. If you use hot water then the boiler is going to have to run sometime. I would think about maybe adding a Heat Manager to your boiler to shorten the number of firing cycles. I have basically this same set up with a cold start but I also have a large solar preheat system and do turn my indirect tank off on good solar days. Perhaps that would be a better investment than just changing outto a gas heater.

Thanks for the replies. unfortunately a solar system here is not really an option. A good rain powered hot water heater might be more the answer. The toyotomi is actually a oil fired on demand hot water heater. The boiler mate does seem to lose a lot of heat. It is always pretty warm to the touch. I thought about insulating it, and have read some forums about using Phosphoric acid nickel safe ice machine cleaner to clean out the coil, and that seems to have improved the efficiency for some people. I was thinking about just replacing the boiler mate with the toyotomi om-148 on demand water heater just for the domestic side as I have one that provides hot water for my wife's small restaurant and that seems to keep up just fine using a minimal amount of heating fuel. but then I noticed the bigger unit that is supposed to work for hydronic heating as well as supplying domestic hot water. so I thought for a couple hundred bucks more, why not just replace the whole thing. And when the wood stove is operational the hydronic system almost never cycles. I don't know if the om-180 is a newer unit, but there doesn't seem to be a lot of info out there. I had thought of talking to a dealer, but they kind like to sell things, and I was hoping to get a more unbiased opinion before I talked to a dealer. I am also wondering if anyone knows how many square feet a toyotomi might be able to handle. the house is about 2800 square feet. the weil mclain I have is rated at 100,000 btu and the om-180 is rated at 148,000 btu so I thought it might do the trick, but I am no expert, just a motivated do it yourselfer.

Sure seems like a lot of bother and expense to replace a working system that you only use occasionally when your not burning wood or to supplement the wood,payback saving may be hard to justify.Even a new system would need to cycle periodically under the same conditions.Steam man had a good point about insulating the boilermate and surrounding pipes.I also like the heat manager idea it would limit cycle time and increase the longevity of your existing system.

Ok, I forgot to address the heat manager. I have no idea what that is or how that works. Also, while the system works, my fuel bill was around $700 last month. That was without the wood stove burning. Just moved into this house this winter and though I have a good wood supply, it is mostly green, so kind of a pain to burn. After seeing the fuel bill I figured I would go ahead and start burning some. I feel like the boiler cycles on a LOT without the wood stove burning. Though I feel that the existing system is technically working, it seems to be using a lot of fuel for what it needs to do. it seems like it spends a lot of time keeping a 40 gallon tank of water hot so that we can use hot water twice a day. We cannot take a shower for more than about exactly the time it takes to get clean. (personally I like to linger for a couple of minutes under the hot water. it is cold here) And we cannot fill a bathtub with a hot bath for the kids. and when the hot water runs out, BAM! it is gone. it doesn't fade. it goes from hot to cold in about 20 seconds. I don't really think my system is working properly. and I feel like it is an old system, installed when fuel was a lot cheaper, so I was looking for options.

If you were to change out the system would you do it now or wait for better weather? If you would wait then why not insulate the tank for a very small investment.What is the tank temperature set at?You could increase tank temp for more hot water but would probably need a tempering valve so no one would get scalded.

If your boiler cycles on and off a lot then it is plenty big enough,a simple boiler control would allow lower boiler water temps and longer cycle times.Tekmar is one that I'm familiar with and there web site does a good job of explaining there uses,I'm sure there are others as well.

You may very well need to upgrade ,just throwing out some options.

I use an OM 148 (which is a DHW water heater) for backup in our heating system.
The 180 is a better choice for heat and hot water.
I think the higher setpoint would allow it to short cycle less, which is something the 148 does.
Short cycling does not seem to adversely affect the oil consumption, although I am sure that it must.

Both units really need a fine oil filter like a Garber. They are almost completely silent.
On the downside, they are more difficult to clean. The burner is not like a conventional US burner, but it is accessible and fairly simple
to get into.
Since you are in Alaska, get spare nozzles. Also buy the service manual, unless there is someone local who services them, your local oil guy
might not want to touch it.

I like them

There's something else going on here. I don't know what it is but it's not normal. Lots of cycling, not enough hot water to take a shower. I'm no expert but I think there is something wrong like the Boilermate is half full of crud and is trying to heat the water through it or something like that. Perhaps those with more experience could hash over that theory here.

You have a cold-start boiler with an indirect. Tied to that boiler the Amtrol has a capacity of over 170g/hr, so you should be able to fill tubs and take a shower no problem. I'm guessing as well that your tank may be filled with sediment, which would cause two things: The first would be the lack of hot water and the second would be the constant cycling of the boiler to keep a small volume of hot water hot.

How long does the boiler cycle when no one is using the hot water? It should be around 10 minutes (give or take) but definately longer than a few minutes.
If you have the newer boilermates it may have an adjustable differential which you could widen to cut back on cycling.

I have a similar indirect tank and have bunches of hot water. Could a water softener help with the mineral deposits? How about if the controller isn't set so the hot water gets priority when the other zones are running?

Personal experience with nearly any of the instant on water heaters has led me to believe that I wouldn't give a plugged nickel for any of them. We've worked with Rinnai, Bosch, Takagi, Rheem and others and virtually none of them perform as stated without quarterly maintenance. 5-8 years is about the life expectancy of any of them. If it were me I'd go a different direction.

Yeah, but they're easier to get into a crawlspace than an indirect! No wonder installers love them.

At my age (just had a birthday this week) I humbly submit that mechanical equipment should absolutely never, ever be installed in a crawlspace. If there is not a basement available then it should be properly displayed in the living area of the home like it should be in the first place.
A well done mechanical system is a work of art. Why would a person hide it in a flippin crawl space.


Feelin a little cranky this morning............

Any indirect tank with a finned copper coil will be susceptible to scaling up, like this one. This was in a home with hard water and looked like this about 6 months after it was installed. The boiler short cycled all day trying to recover the tank temperature.

Changing to a tankless style will just move the problem to a different appliance, better to analyze and treat the water, first.

It's hard to acid flush this much out of a coil in a tank. Better to remove it and try cleaning, or replace it. The problem with enough acid to clean a coil like this, it really attacks those paper thin copper fins also.

Also look for ways to lower the heat load on your home, that will be better money spent opposed to replacing equipment.

hr

All I can say is "wow".

I agree, WOW! My coil is not that bad. I drained the tank (nice clear water though no heat to it till I got about half of the water out) and looked in through the fitting at the top. I can see the coil, and I can see the fins on the coil. so I don't think the coil is too dirty, but might have a bit between the fins. I am slightly baffled by the fact that only the upper half of my boilermate was warm. I had forgotten that point when I started this thread as I looked at it week or two ago.

Thanks for all the opinions by the way.

I get laughed at when I'm at work for the time I waste when I'm checking out the mechanical rooms. When its right its right, and its beautiful.

The tank is going to stratify (I think that's a word) over the course of the day/cycle. That's not a big deal, and in fact will help by keeping down the number of cycles during the day as you siphon off for smaller loads. I'm not familiar enough with that tank to know where the auqastat is installed, but I'm going to guess the bottom 1/3rd.

Can you give us a picture of the top of the tank? It sounds like you may have hot water escaping through a gravity loop which depending on the rest of your home's plumbing could be hurting the tank's performance. There should be a heat trap on the tank.

A gravity loop robbing performance may explain why you're getting more cycling but you still should have a more than ample supply of hot water. I know that in my old house I didn't have a mixing valve on the indirect and was dependent on the the tank's aquastat to limit the hot water temperature (not good). There was a lag between when the tank would run low on hot water and when the boiler would get hot enough to heat more water (very common with cold start boilers). By installing a thermostatic mixing valve I was able to bump up the water temp which did three things: 1. It kept the tank temp around 135-140 degrees which is much better from a bacteria standpoint. 2.) It keeps the water temp at the tap much more stable, eliminating cold/hot spots and plumes in the tank. 3. It makes a 40 gallon tank behave like a 50 gallon tank.

I've had good luck cleaning coils and check valves, etc. with that stuff you buy at the discount store. "CLR". Appears to do little damage.

Agreed, something ain't right.

Up until i went to a wood boiler, I used a Weil McLein(80,00 btu oil furnace) w/ an Amtrol tank with it. Worked perfectly. I have a 2 story house in northerm maine. NEVER run out of hot water. Could run both showers, for a long time. We have 2 full baths.

That's what I'm talking about with a tankless. If one of those had been in that particular house it would have been dead long before 6 months. Results of cleaning the heat exchanger in those has been "spotty" at best. Tankless water heaters are OK if you have perfect water. And I do mean perfect. No iron, no hardness, no TDS. At least in that situation the owner could attempt to clean the coil.

well, after some investigation I have found that I have a L8148A1017 aquastat without the optional low limit control. after burning the wood stove all night and turning the boilermate off last night, my boiler is down to 90 degrees. I am assuming this is then a cold start setup yeah? I guess I can live with this boiler. except it seems like such a waste of energy to have to heat that big cast iron boiler if the wood stove happens to burn out. Also, we just don't use hot water all day long or all night for that matter. showers take place in the morning or evening. dishes happen in the evening. hot water is probably only used about 2 hours out of any given day. that is why I was thinking of the on demand heater, and then when I thought of the boiler having to heat itself up, I thought why not the bigger on demand, and get rid of the whole works. I agree that something is probably wrong with the boilermate (insulation, fouled coil) but I also think keeping 40 gallons of water warm to be used a couple times a day is a waste, but perhaps I am just ill informed.



EDIT: I forgot to mention, my boiler is 16 years old, and I am assuming the boilermate is the same vintage. when I look up the serial number for it, the amtrol site can't find it, but it was at least manufactured before 2000.

I don't know what is wrong, but some people have put timers, like a clock thermostat, on the water heater.

I've got a Weil-Mclaine ultra 105 (instantaneous condensing boiler) for my heating needs and a Rannai instantaneous condensing boiler for my DHW. I've been using both for about 6 years on well water that is not so good. The water has high levels of calcium and iron among other things. We do have a water softener and an "iron curtain" now, although I seem to be lazy about always keeping salt in the brine tank. We heat a 4600sf ICF home in the midwest (ave temps during this time of winter 2/0's but typically very windy here). We often get -10F to -20F for short periods.

As far as problems that others are having, can't say that I've been anything other than very pleased except for one problem with the WM boiler that had to do with that model (but supposedly has been fixed since then). Gas bills run ~$140/month for the worst 3 months of the year. We total about $1100 annually so can't complain. If it were me, I would do it all over again and think that you are on the right path, although I am not a professional. During the summer when we are only cooking on gas and using DHW actual gas consumption is $6-7/month.