Beckett AFG Nozzle Sizes, Pump Pressure and Ret. Heads


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Old 09-25-08, 05:11 PM
J
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Beckett AFG Nozzle Sizes, Pump Pressure and Ret. Heads

Hello to the group,

I recently purchased a home and it has installed a Peerless WBV04 Boiler with Tankless coil and Beckett AFG gun.
The home is a small cape 4 BR built in the 50's with the old style hot water convectors. The 1st floor is 660 sqft. I have 2 zones: the 1st floor and the 2 convectors in the 2nd floor bedrooms and the 2nd zone is about 18 feet of baseboard in the basement. The house is well insulated with thermopane windows.

I suspect but am not sure the 4 section boiler is a bit large for this house. It was installed 3 years ago.

So on to my question and concerns, after checking the unit out I see it is firing a 1.10 80 B nozzle. The AFG has an F6 Retention Head.

Since the AFG runs a pump pressure of 140 psi I figure that gallon10 nozzle is more like 1.35 gph which seems like a whole lot.

I am wondering if I can or should run a smaller nozzle say about .90 80 B which at 140 psi flows about 1.08 gph.
And lastly is the F6 head ok to use with the smaller nozzle? I thought I read somewhere the F6 is OK between .85 and 1.65 (not sure how the head number correlates with nozzle size)
My goal of course is to hopefully burn less oil by not firing the boiler any more than needed.

Thanks in advance for any info. and advice.

Jon
 
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Old 09-26-08, 07:50 AM
J
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I don't pretend to be a professional, but I have a lot of experience maintaining my own antique system.

Here's a summary by peerless:
http://www.peerlessboilers.com/Produ...productratings

It looks like the WBV-04 was designed for nozzless from .95 to 1.5. So it should be fine to get a .95 nozzle installed. As to pressure - why do you assume it is running at 140 psi? My system had an adjustable pressure; it should be possible to get it adjusted down to 100 psi if it isn't already there. Changing to the smaller nozzle will not only burn less oil while running, it will also improve the efficiency of your boiler (according to the page I linked above). Head change wouldn't be needed.

I never had the gauge to measure oil pressure, so I would always get pressure adjustments done by a pro as part of a service call. You certainly can (and should) ask for a nozzle change at that time. In fact you can get all of this done along with your annual maintenance call to clean the flues and filters. If you find your system isn't putting out enough heat after the nozzle change you can always get it changed again (this seems unlikely - it sounds like you have much more heat output than you really need).
 
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Old 09-26-08, 07:54 AM
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Wow that seems like a large nozzle for a small house. Just to give you a comparison, I have a 1500 SF moderately well insulated house in upstate NY and have a Weil McLain with a tankless and I am using a .65 gph nozzle at 150psi and we have no head issues or hot water with 4 zones going.

I don't know your heat loss, but does the boiler short cycle a lot?
 
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Old 09-26-08, 01:33 PM
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Since you are buying all that extra heat for your home you may as well share some. Send it my way. That unit is way oversized unless your home has no glass in the windows.
Changing the nozzle size will not save you enough to notice. The efficiency is being strangled by the extra large boiler. When you replace the nozzle with a smaller one you take a chance of condensing the chimney and destroying the chimney and the boiler.
BTW the higher pump pressure is a plus and gives a cleaner and more thorough burn. That is why all manufacturers went to higher pump pressures.
 
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Old 09-27-08, 07:59 AM
J
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Sorry you're quite right about the oil pressure - I looked up the specs and this is designed for the 140psi pressure. So reducing the pressure would definitely not be something I would try. It should also have an F4 head, not the F6. The F4 is specified for .95 and 1.25 nozzle sizes, so it looks like the previous owner already downsized your nozzle from a 1.5 to the current 1.1.

http://www.peerlessboilers.com/Deskt...hod=attachment

I don't know whether it would make any noticeable difference to change from your F6 head to the proper F4 (more experienced like rbeck would know). And my guess would be that since this boiler is shipped from the factory with a .95 nozzle then there would not be condensation problems running with that nozzle size, but once again I'de listen to those with more experience here.
 
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Old 09-27-08, 10:41 AM
J
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RE:Beckett AFG Nozzle Sizes, Pump Pressure and Ret. Heads

Thanks to all who replied, I think I may try a smaller nozzle, also I am considering adding a beckett heat manager to the system. Here on LI as a trial they gave them to all the residents in Levittown and the average savings was 14-25%.
Seems the boiler is a bit large but swapping it out is out of the question at this time. I suppose condensing may be an issue with the smaller nozzle so I need to figure out how that can be avoided.

Jon
 
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Old 10-12-08, 05:06 AM
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Follow up nozzle size pump pressure etc.

I calcualted my heat loss and come out with about 76,000 btu which includes my tankless hot water coil.
Looking at the WBV04 manual and stickers affixed to the unit and also gama efficency ratings I decided to go with a .85 80 b nozzle. While this is still a bit big it seems to be the most efficcent 87.0%. At my pump pressure it will be flowing about 1.02 gph. Much better than the 1.3 I was flowing before.
Observations are less cycling and longer times in the order of 5-6 minutes.
 
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Old 10-12-08, 05:49 AM
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Sounds like an improvement. That will help a little on the fuel bill. One question...What did you mean by which "includes my tankless hot water coil"?
You never add anything for domestic hot water coil.
 
 

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