1001 th time

realolman

I imagine this has been asked 1000 times Here goes 1001

I'm about ready to rip out my Burnham V74 boiler and heave it down over the bank. I think it uses too much oil.

What brand would you recommend installing

Constantin

Hi Realolman...

... now I have a couple of questions:

Are you running steam or hot water?

What kind of emitters are on the system? Radiators, baseboard, hydro-air, etc?

If Steam, have you measured the EDR of the radiators?

Do you know what the heat loss of your home is?

realolman

65,000 BTU hot water, mostly baseboard, 2 radiators 11,050 and 14,722 EDR, 98 ft 3/4 in baseboard, 2 circ. pump

used to use domestic tankless water heater.. I haven't been using it lately.

V 74 is 135 000 with 1.1 nozzle @ 14o PSI I have 1.0 nozzle @ 140 PSI

adambuild

W!

Weil McLain Ultra Oil!

Floyd

I second that...

Just unloaded a UO-3 DV today... that SOB is HEAVY!!! But better than the 5 that I'll bet starting up on Fri.
Haven't done a direct vent yet, but want to see how it works... never was thrilled with separate power ventors...

And... you can get a low fire kit to back the 3 down...not sure what the numbers are off hand but I'm sure that the WM website would give the specs.


Floyd

Bob Forand

Crown Freeport

Crown Boiler . com

tom_49

Realolman,

I too ripped out my Burnham V73 last year.

I installed the Viessmann Vitola. This boiler has NO low temp limits on return. My house has lots of High output bb and 1 radiant zone.

I have outdoor reset and I have set up the heating curve where the pump runs just about all the time ( may be installing var. speed pump soon). I have 5 zone valves for "high Limit" control on my different zones.I have never seen this boiler get over 146o output temp, and I live in Mass. My house stays at a constant 70o.

I saved 18-20% on my oil bill last year based on previous years, taking degree days into consideration.

There are lots of choices out there, but I am very happy w/ the Vitola. I am installing one soon in a customers house.

Good luck, Tom

Cunner_2

Burnham?

Was there anything you didn't like about Burnham other than the fact that the boiler was probably oversized to begin with and had a tankless? I've been using the Burnham MPO's and they have been fantastic. I did a similar job last september where I ripped out a Burnham V15A with a tankless and installed a MPO147 with a Taco 700 Reset and a Indirect, cut their bill in half!

Just my Thoughts

S Ebels

Good ones that I've used

Good ones that I've used and are all worth considering; Buderus G-115 series, Viessmann Vitorond, Viessmann Vitola (the M1 Abrams tank of the boiler world) Crown Freeport. These will give you a side range of prices and features from basic (freeport) to the top of the line (Vitola)

I've heard good things from the guys here on the Wall about the Burnham MPO.

Condensing oil is a big ?? in my mind due to very limited field experience of these products in the US.

I'd be mighty leery of anything using other than Cast Iron or Stainless in an oil fired boiler.

Uni R_2

Peerless Pinnacle?

Well, if you want a condensing oil boiler you're in luck. The Peerless Pinnacle Oil is exactly the size you need and should be pretty well tops as far as being good on fuel.

Now the big question is, are you or your contractor willing to install a new product?

S Ebels

Condensing oil....worth it?

Just thinking out loud here........With a gas boiler you can easily pick up 6-8%....maybe even 10 on the right system because of the amount of latent heat in the flue gas. That makes using a gas condenser a no-brainer in nearly all cases. The thing with oil is that there is much less latent heat in the flue gas. Look at a Viessmann Vitola for instance. I have installed several in both oil and gas versions. Same boilers with the only difference being the burner. On the gas burners combustion efficiency on the Testo will run 85-86% with normal water temps. On the oil fired models that we have done, the combustion efficiency will run between 88 to as high as 91% depending on the boiler water temp. That being the case, you're only going to pick up maybe another 3-5% at most with a condensing oil boiler. For the added expense, complexity and potential for more maintenance due to the condensation, I would want to study that alternative long and hard.

The thing to remember is that the gas condensers usually modulate their firing rate also. I don't think the oil condensers will do that.

Constantin

Hmmm...

I thought the latent heat in gas systems was higher than in oil-fired systems, hence the higher efficiency limit that oil systems can be fired to before they start condensing (was it 13% latent heat vs. 7%?). I have only fired my Vitola with oil and achieve a stack temp of around 250-275°F with zero smoke and 12% CO₂. I'm not sure where that is, efficiency-wise, but I'd like think it must be pretty high.

For modulation or step-firing, a condensing boiler will likely have to have a single combustion chamber like the VitoPlus on the oil side or one of the many residential gas-fired mod-cons out there. Based on Brad's real world experience, it's quite possible that step-firing or, better yet, modulation would yield a higher net benefit for a consumer than just condensation by itself.

Constantin

Lots of good choices...

... I have heard good things about the Burnham MPO, Buderus G115 and the Viessmann Vitola. The most important thing is finding a good installer and the right person to maintain the system later on. Make the installer right-size the boiler, though.

I'd avoid tankless coils wherever possible and use indirect water heaters instead. If they're well-insulated, they lose very little in standby and recovery is faster than with most standalone water heaters.

Unknown

RE: V74 Burnham

Replacing the V74 is certainly one option but there are certainly other more reasonably affordable options. One is to have your contractor either turn down the Low Limit that the boiler is always operating off of regardless of a heat demand or not or change out the control with a "cold start" control. If the control is replaced it may not be a bad idea to replace the tankless with a tapped cover plate and new gasket as the old gasket may weep if the low limit is disabled.

The other or additional viable option would to have your contractor set the existing burner up for a lower firing rate. The Installation manual has all of the setup criteria in it for rither a "Mediun" firing rate (V74WM) or a "Reduced" firing rate (V74WR). This is a very inexpensive procedure and will more closely match the output of the boiler to your actual needs. Or you could change it out for a newer boiler such as the Burnham MPO. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

joe_87

replacement unit for netaheat 55

realolman

Thank you for your recommendations. The low limit on the aquastat is disconnected. It is now only being used as a high limit.

One of my main concerns is the high stack temp.

Realistically, what should the stack temp be?

V74 with a 1.0 nozzle @140PSI, 6.0% O, 11% CO2, 87.1 % eff. 0 smoke, -.03 in draft? I'm getting 650 after 4-5 min. burner run and 150 deg water hi limit. Is that the best heat exchange I can expect?




The flues are clean. The other day I cleaned out the water side with a product called Herculese "Sizzle". It bubbled gas for about 7 hr, and was still acidic afterward, indicating to me that it had removed all it was going to remove...

Virtually no difference.

As the water I drained the out in the first place was clear. I thought to myself..." You're messing up here. You're dumping fine wine airless water outta your boiler and replacing it with kool-aid". But it's been bugging me for a while, and I knew I wouldn't be satisfied until I tried to determine if there was something on the water side of the boiler. At least now I'm satisfied about that.


It already gripes me that the tankless is not economical to use.... Now it's beginning to look to me like that boiler is just not very efficient. I'm pretty disappointed about it.

Unknown

Combustion Numbers

The first thing that gets my attention are the Combustion Efficiency numbers as compared to the stack temperature you say you are running. I'm curious, who performed this combustion test and with what type of equipment? Stack temperatures that high are not conductive to 87% efficiencies.With stack temps that high I would first suspect that the flue passeways have a pretty good coating of deposits on them or that your draft is excessive.

Aside from that, my best advice would be to set the burner up for one of the lower firing rates. That will bump up the overall AFUE efficiency a couple of points and should reduce your oil consumption significantly.

Glenn Stanton

Manager of Training

Burnham Hydronics

Constantin

Hmmm...

I wouldn't beat yourself up about the boiler too much re: efficiency if those combustion efficiency numbers are correct (which is questionable considering the stack temp), but I defer to the experts here (just a homeowner)...

FWIW, the Bacharach chart I have shows for 11%CO₂ and a net stack temp of 380°F a net efficiency of about 83%. The net stack temp = gross stack temp - room temp, which I assumed to be 70°F.

IMO, a bigger issue is that your boiler seems to be much too large for the load in the house. Your input rating is somewhere north of 160kBTU, at DOE output you're around 135kBTU/hr, your heat loss, even on a design day, is always less than 1/2 of the boiler output.

Downfiring the boiler to the point where it matches your heat loss is unlikely to receive an official blessing and may be unsafe... are you willing to start experimenting like Ron Schroeder with his DV rig?

A buffer tank might help, allowing the boiler to fire for longer lengths of time, but the net benefit depends largely on the water content inside your boiler (which may be high), your BOP, etc. The more water is in your system, the less sense a buffer tank makes, IMO, as that water starts to act like a distributed buffer tank.

Unknown

Constantin

Just curious what this is really supposed to mean.

"No amount of downfiring is going to make this boiler efficient and safe at the same time..."

As I already stated above, we have always had 3 "tested and published" firing rates for this boiler and downfiring the boiler to the "published and tested" lower firing rates will in fact more closely match the intended required heat load he has here. Along with that will come longer and "more efficient" burn cycles. Now if you would care to clarify what you mean by "safe" we would all sure appreciate it!

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Constantin

Sorry about that...

... I didn't mean to imply that your suggested settings are unsafe, far from it.

Do the allowable nozzle suggestions for this boiler reach down to the 0.5GPH range? As reaolman would ideally have a boiler with this sort of input rating to match his homes heat loss on a design day. I simply doubted that the 74 can be downfired to 0.5-0.6GPH with the blessing of the Burnham Corp. given that the smallest published allowable firing rate I found for this boiler is 0.8GPH. But I am happy to stand corrected.

Ron Schroeder is running a 0.5l/h (i.e. ~0.13GPH !!!) nozzle in a Buderus G115-21 with a direct vent system, a boiler normally rated to accept 0.6-0.75GPH nozzles. (see here for a post describing his system) Ron does not seem to have condensate issues eating out the flue, the boiler, etc. to the extent that we would all expect severely "underfired" systems on regular chimneys because his chimneys are almost non-existant (3" long).

I think we can both agree that Realolman would benefit going to the lowest allowable input setting on this boiler as long as it doesn't lead to condensation in the chimney system, etc. Testing the stack temperature is good insurance, as is careful flue sizing, inspections, etc. At 0.8GPH, his boiler plant would only be oversized by 50% instead of 100% on a design-day.

Thanks for the heads-up. Just goes to show that I should not type before having my morning coffee. I have re-worded the offending paragraph. Does it read better now?

Ragu_5

Ah, Grasshopper...

You have all learned the mystery and the intricacies of this heating world, and I am very proud of you all.

I Think that Master Weezbo may have to comment on this one.

Gee, maybe if we are all really lucky, we can also get MAD DOG in on this one.

I will wait patiently and subservient in the background. Jack

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

Reduced firing rate

The "approved" reduced firing rate uses a 0.75 nozzle and nets out at 85,000 btuh. This is a significant reduction of output to the amount of 62.5% of the normal rate. It also boosts the AFUE percentage rating from 82% to 86.2%.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

realolman

On the printout the stack temp is 567 and the ambient is 84. I'm sorry... that was obviously misleading. I was just trying to show how it was set up.

which leads me back to my other question. What should it be?

If you read the temps long enough it'll go to 650 deg.

Unknown

Stack temperatures

Stack temperatures can vary all over the place depending on many factors. These could be the time of year that the testing was done, the water temperature in the boiler when it is done, draft or chimney conditions and where the test is being taken in the flue pipe. These types of boilers typically do not have a real big pressure drop from the combustion chamber to the discharge or breech. It is not uncommon to see them come in in the high 400's to low 500's. What is important is that the test is done with the boiler operating under steady state conditions.

If I recall correctly you said that you were having this done with the boiler set at a 150°F High Limit setting. Operating a boiler like this with temperatures like that is not necessarily steady state. As you also stated, you are only using a fraction of the heat that this boiler and burner is generating and if it is not giving it up to the system you may have wasted btu's going up the flue. If you could post everything that is on that combustion test printout, it may tell what may be going on.

My advice again would to have this set up to the "WR" firing rate which only uses a 0.75 gph nozzle. The cost of doing this is minimal but the benefits will put money back in your pocket via fuel savings. This will eliminate for the best part most of your short cycling and allow the burner to stay on longer with less input thus creating conditions a bit closer to "steady state". Also make sure that all of the flue passeways in this boiler are absolutely free of any soot coating. I minimal amount of coating on those surfaces can sure account for the high temperature readings.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

realolman

thank you very much for your recommendation

I have looked through my installation and operating manual several times, and can't find anything about the reduced firing rate.

Unknown

V7 Setup Data

Somewhere in that manual is a Table that looks like this. I have highlighted the setup data for the V74 Water boiler. Please note the reduced pump pressure and requirement for the low fire baffle. This is for a Beckett burner. If you have a Riello or Carlin burner then use the appropriate data for that burner. Apparently this table was never transformed to .pdf format in the On-line V7 manual on our web site. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

frank_25

FOR MY MONEY

> You have all learned the mystery and the

> intricacies of this heating world, and I am very

> proud of you all.

>

> I Think that Master Weezbo

> may have to comment on this one.

>

> Gee, maybe if

> we are all really lucky, we can also get MAD DOG

> in on this one.

>

> I will wait patiently and

> subservient in the background. Jack

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 428&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_



I'd price the above, and a Peerless ECT series w/ Riello burner. Good efficiency, solidly built, priced right not too expensive. Throw on a good circ, do the right thing and you'll love yourself. Ya get a tax break with those boilers also.

realolman

thanks

I've been looking for that.

There's one similar to this in my manual, but it only has one entry for each of the v73- v78 with a beckect afg burner. For the V74 it has only a 1.35 firing rate.
I have the F4 head. I see on here it takes an F3 head.

I think that is probably the route I'll take. again thanks. You've been very helpful and very kind.

EBEBRATT-Ed

I don't see anything but an upside for downfiring units. You have to be a decent oil tech to do this and have a large dose of common sense. With the right testing equipment it can be done on any boiler or furnace. Make some changes, go back and check the unit a few times to see what is going on and if you can spend the time with it it ill be ok.

In this case Burnham has already done the testing for you at a lower firing rate. Your already halfway there. JMHO


ED