Toyotomi OM-180 down-fireing

Solid_Fuel_Man

Anyone have any experience with one of these?  Toyo specs a special "XAJ" Got one from my supplier and it's just a Delavan .85GPH.  The pump pressure is 145 psi so around 1-1.1 GPH.  I would like to downsize this boiler as it short cycles like crazy, wondering if anyone has run into this before. 

Thanks for the great info and great site!  

Taylor 

Paul Fredricks_3

Don't touch it

It is a special nozzle.  .85 60° XAJ

The pump pressure is 192 PSI and you have to use their pressure gauge to check it. The fittings are metric ball flares and no one has the parts to adapt to them.

They short cycle. That's just how they work. It's not an issue as far as operation goes.

pipeking

just wondering

how is it being used,dhw,or a boiler?

Paul Fredricks_3

both

We put in a bunch of these units over the past 6 years or so. We have about 50 to 16 148's out there for hot water, and we have 20 or so 180's doing either hot water or as a boiler. All of them short cycle....at least compared to a "normal" unit. But they were designed to operate that way. The only way to stop the short cycling would be to crank up the flow rate through them.

pipeking

hey paul

u don't have to do combustion anaylasis on them huh? they come set from the factory ready to go, the reason i ask i was wondering what efficientcy u got out off them?

Solid_Fuel_Man

I know the XAJ is special

The can is so small it fires into, I figured the spray pattern would have to be short.  This unit is piped as a boiler.  What is the difference in the BS series and the OM?  The BS is for Kero and the Oil Miser is oil.  Other than the 3/4" vs. 1-1/4" fittings is it just a listing or are there actual parts and design differences? 



Taylor

Paul Fredricks_3

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The 148 and the 180 are basically the same. the 180 has an adjustable differential that we usually set at 18° for heating applications. We did use the 180 for hot water production, but I think the 148 is better due to the piping arangement which helps limit the flow.

You have to efficeincy test the unit, just like any other. Not that you can adjust anything but pressure. But you have to be sure it's running right. I typically have the home owner run the hot water at a sink until the boiler is cold, then max the aquastat to get the longest run time possible, usually about 2 minutes. Efficeincys run around 82%, IIRC. In our tests, vs an Aero 30 gallon, it used about 30% less oil.

Dirk_4

Use 0.75 nozzle

I have an OM-148 that I installed myself. I use a normal .75 nozzle with no problems, though it may produce less hot water than before, I don't know. As a boiler, I would imagine it would run much longer with the smaller nozzle, provided the combustion is set up properly. Since they don't provide a way to adjust the air, you have to improvise. I have used it for about 10 years now. It is generally very reliable.



If you are using it with a chimney and their chimney adapter, be aware that Toyotomi were completely wrong with the combustion air settings. They admitted it to me in a phone conversation a long time ago. It needs far less air, and I had to improvise a way to reduce the air flow. I have a digital exhaust gas analyzer (Fyrite Pro I think) that I used to set up the combustion.



Another modification that I made was to provide quick disconnects on all the wiring that goes to the burner. That way, I can take the whole burner assembly out for cleaning and nozzle replacement.



I have never adjusted the fuel pressure. I don't recommend adjusting the fuel pressure because you want the highest that you can get because it provides better atomization of the fuel. It's better to use a smaller nozzle to reduce the fuel flow, if necessary. Their nozzle is an "extra hollow" cone, hence the "x" in the designation. I have found it works just as well with the normal Delavan hollow cone nozzles.

Paul Fredricks_3

air

I've seen that the excess air is very high with these units and mentioned it to them, but never got a resolution. I'm surprised that you can get away with a standard .75 nozzle. Never tried it, and probably never will. The unit is not UL appoved for that nozzle and we try to avoid lawsuits. If it were in my house I'd give it a try.

Dirk_4

Nozzles....

They told me that it was set for the direct vent system, but since I don't have that I never measured it.



I wasn't aware that the UL rating was for a specific nozzle size. I just replaced it recently, as well as cleaning the nose piece in an ultrasonic cleaner to get it spanking clean. It had been at least 2 years since I'd serviced it.



Their nozzle is insanely expensive, so I don't see the point in using it since a regular one works just as well (I measured it). I understand the predicament of professionals though, of course. You have to do what's required no matter how much it costs.

Paul Fredricks_3

.

I assume listing covers everything. If the unit was rated with only a specific nozzle you'd have to use that one. Any time you substitute a different part that was not approved originally I would think that would be a problem.

Yes, the price of the nozzles is nuts, and it's gone up quite a bit in the last few years.

Solid_Fuel_Man

Ebay

I've scored some nozzles on ebay for less than I can get them at the supplier.  This is a DV install but there seems like a lot of heat siphoning out the vent on standby.  There should be some type of flap either hydraulically operated (like Reillo) or spring loaded to stop the thermo-siphon through the vent.   Just my thoughts, these seem to be nice units, few and far between around here though.

TimeBandit

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TimeBandit

OM-180 nozzle

What is the difference between a Type A and a Type XA nozzle?



The XA nozzles were developed to produce an extra hollow and more compact spray pattern that the European and Asian burners required. The XA nozzles also produced better emissions and performed better in the colder climates then the type A nozzles. The XA nozzle line is not yet available in the U.S. market, and are only available in the Asian and European markets.

Solid_Fuel_Man

Thank you!

I'm going to give them a call.  It's funny how the XA is made by Delovan in the USA and we have to get them from Japan.  We make them, ship them there, they ship it back in a Japenese bag and add $30 to the cost.  I still would like to fire this thing at something like .5 or .6 gph  If I knew a regular type A nozzle would work..... I still may try it as it's only making hot water for the summer.



TS 

TimeBandit

Careful!

Modifying the appliance by using any part not approved by the manufacturer will void the UL listing of the piece of equipment... Meaning that should anything go wrong ie. fire, CO poisoning, etc. the liability is on whomever made the change... Insurance will not cover.

TimeBandit

Also

The aforementioned change will also void your warranty... Limited 10 years on the OM-180

Solid_Fuel_Man

It's in my house

I bought it used, and the PO had welded the HX after he over-torqued one of the nipples.  I'm pretty sure the warranty is void now. 

Taylor

TimeBandit

understood

Just remember... safety first, savings second. I would be interested to see what results you get. One issue to consider, downfiring will result in lowered flue temperatures, which will lead to increased condensation, the result of which is very likely to be more rapid rotting of your exhaust/flue and the baffles in the heat exchanger. The unit is designed as it is for a reason. If you do decide to make some changes, please post what you do and what result you get.