Oh, I was thinking again about draft hoods.....Boilerpro

jim sokolovic

Correction on spill switch...

I referred to the spill switch as being "auto reset", but now that I think of it, I've only seem manual reset used. It's all Kal's fault, you know! :^0

Kal Row

i didnt's see a red reset button on the spill sw

of the last SX-150 i installed - unless it magicaly appears when triggerd

jim sokolovic

Please check that job again...

The switch is a Thermodisc 601T15, with a 235* F setting stamped on it. All of our spill switches are manual reset, so I don't see how anything other got shipped. If you find anything else, contact Noel in Tech. Service.

Kal Row

ok - going back there anyhow

to use rhomarwater's cleaner and conditioner system - being that the tekmar 361 runs those baseboards down low - the black stuff from the old system coating the insides become a heat transfer insulating issue, so i am going to clean it with what is supposed to be the best stuff out there - it cost a fortune almost 200 for a gallon of each chemical
the conditioner/inhibiter is supposed to keep the system nice with good ph for a long time
I’l let you know when it’s done

www.rhomarwater.com

Mark Hunt

So why


aren't there two or more from the factory?

Mark H

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Mark Hunt

Buddy!


No drinks, just sick and tired of the same old, same old.

Time to kick it up a notch.

Jump in any time bro!

Mark H

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Kal Row

my bad

sx-150's spill is a manual reset - mixed it up with a York on the roof packaged ac unit, auto reset fire sw failed in a way that if you blew on it, it would cut out - replaced it with a manual reset of course (york’s own fix) and the problem solved, previous techs had changed everything, the poor store owner was into it for $1000, before i got to it, and replaced the rollout/spill, haven’t these people heard of a test light and the wiggle test!, they get so flustered with the electronics, that they forget the basics!! – but, that’s not that bad a failure, had a laars pool heater whose Fenwall control just turned on the gas without the hot surface igniter or checking the flame rod, “cudd-ah blowed aahp de oh’l owss”

jim sokolovic

Kal, what is \" bad\"?

Are you having a problem with that boiler, other than yucky water?

Kal Row

no - everythings ok

just that in another thread we descused at length low temprature baseboards - and being that i have a 361 that will mix the baseboards down low on a warmer day, i wanted the system supper clean, since even a thin coating of gunk on the inside of an old system can be insulating with supply temps down to 100f or less - also, had the homeowner use, the blowing end of his vacumn cleaner to blow out all the baseboards

Unknown

Really do not want to get into this discussion

but I guess I am a glutton for punishement.

Draft Hood definition from American Gas Association training manual:

1. Provide for the ready escape of the flue gases from an appliance in the event of no draft, backdraft, or stoppage beyond the draft hood,

2. Prevent a backdraft from entering the appliance, and

3. Neutralize the effect of stack action of the chimney or gas vent upon operation of the appliance.

To the best of my knowledge draft hoods came about to try to overcome problems with pilot outage. They came as a seperate device and it was up to the installer to place them at a point that would best serve to maintain some kind of stability as it relates to draft. The problem with the pilot is that it is also a burner and has its own products of combustion. With out proper draft those products will recirculate and put the pilot out(CO2 being a quenching agent). The draft hood at best did a fairly adequate job in most cases. It is probably a device that has served its time and needs to be retired. Standards need to be changed.

Many tmes when draft was excessive and draft hood could not be moved (it was fixed and built in) we would use a neutral pressure point adjuster. The books showed the adjuster placed between the breech and the draft hood in many cases. My experiences with that showed that placing it as close to the chimney as possible worked a lot beeter to reduce total draft when it was excessive -.03, -.04 -.05 etc. This is allowed by code by the way as it is a fixed damper (see National Fuel Gas Code 2002 sections 10.13, 10.14, 10.15)

There has always been a procedure to help with draft which was to locate the equipment so that adequate "rise" (vertical unobstructed height) directly off the top of the equipment would create in effect some "self venting" if you would.

What about barometrics on design gas equipment? We have in the gas industry been using them with power gas conversion burners for years, why not on design equipment. Simple answer the standards do not allow for them it would seem. That is debateable when you look at the fact that in setting up and testing equipment we are admonished to make it as safe and efficient as possible. What will it do for us (the barometric). It will regulate draft well you say does not the draft hood do the same the answer is that in some cases it will do the job. When it becomes difficult to regulate draft then it has been my experince that a barometric will many times resolve the problem. Without weights it will maintain a fixed pressure at the appliance outlet. The preset pressure is typically -.02" W.C. If draft in the chimney or vent is -.02 the the barometric will remain closed. As the draft in the chimney or vent increases it will open and relieve if you will allowing a stabilizing at -.02" W.C. On gas we use a double swing which allows for the dumping of backdraft or downdraft into the room instead of the equipment. It also allows for control on the low end of draft (the pilot operating all by itself) Keep in mind draft is actually air for combustion at overfire, no draft or poor draft no air and combustion is affected. Natural Draft by definition is created by HEIGHT and Delta "T" (temperature difference). It is however affected by many things and that is when the barometric does its job. The question then is liability when you change the design of a piece of equipment that the manufacturer has received approval for. That is the question I guess that has to be dealt with. As an instructor I am careful to make sure the students I am talking to have enough knowledge and experience in combustion to know the difference. Having said all of this then if you are going to work on gas equipment, I do not try to talk about others oil, coal wood etc as I do not have sufficient knowledge, then combustion testing must be done to confirm your alterations and adjustments. When finished efficency and safety will have been served. Let me say here also that I am not a big fan of vent dampers. Many of them in the field are not even functioning anymore as techs have gotten tired of replacing them when they have failed and have either removed them or jammed them open and jumped out the blown fuse circuit in the primary control. I am not advocating such behavior, just telling how it is!!

Kal Row

ok - let me get this

in essence what your saying is, if i do a long drop tube like my picture above, - i would have to put a tee near the top of it, with a second vent damper on the tee, to effectively shorten the drop tube when the boiler is on, so that it’s length induced draft, doesn’t affect combustion – or else I would have to, field set, the burners for that length – ugh – don’t like either solution, so this idea is dead, we have to go to sealed combustion and that’s that