Joined on February 3, 2007
Last Post on August 6, 2014
@ December 30, 2012 2:52 PM in district steamWhile working in San Fran. I worked in a lot of old hotel, apt bldg's and commercial bldgs that utililized what was called city steam. The steam being generated by large boiler complexes located around the city, than transmitted under the streets at high press. the lines would go into the basements of bldg's and into press. reducing regulators, Most systems were 2 pipe with the condensate return lines piped into a cond. meter. the meters were quite clever, they used a device that resembled a minature water wheel to meter the cond. used. Over the years private co's bought the systems. This became an alternative to bldg owners who had old boilers that were in need of replacement. I am sure this system is currently in use in other cities, It was just quite an experience to get to work around all the regulators, piping and valves
@ December 29, 2012 11:21 PM in old Powers pneumatic thermostat questionI used to work on old peumatic systems and was a U.A, instructor, if you give me the mod. number I may have the old cut sheet. As everyone has said it is most likely a day/night t-stat, look close for a smaller dial with 0-10 degree marking this would be the degree of night setback, as Ed said dual prv's would change air press.to t-stats. These types of systems are still being used in some old bldg's
@ December 29, 2012 12:47 PM in Float & Thermostatic Trap??If you go to yahoo and look up F&T traps under Armstrong they have a good pictorial. F&T traps gather condensate at the end of a line and release it back to the boiler,condensate pump or boiler feed tank by means of an internal float assy. The T stands for temp. the internal element releases unwanted air The internal water seal prevents live steam from getting into the cond. line. You can get a rebuild kit for this trap, you can check the temp. drop across the trap, if the outlet temp.is the same as the inlet than the trap is bad. Traps need to be maintained. I would also clean out that wye strainer or replace it, not sure where the rest of the piping goes. I would cut out all that copper and repipe that whole thing in black pipe with a wye strainer ahead of the trap.
@ December 29, 2012 12:03 PM in lwcoHere is a picture of the inside of the bowl of a Mcdonnell Miller lwco that was not blown down or maintained
@ December 29, 2012 11:30 AM in Help! Problem with Burnham MPO temperature guage and pressure. Scratching my head??Do you have a diaphram style tank, if so have you checked to see if it still has the air charge, you can use a tire guage, should be at least 12psig. the other thing I would check is the fill valve, most have a small strainer you can remove and clean. If the fill valve is old and never cleaned the valve could be rusted and corroded internally, this could cause valve problems with internal valve parts causing valve to overfeed. The fill valve is commonly overlooked.
@ December 28, 2012 1:54 PM in Air Vents v. Vacuum BreakersI agree with all the pro's that have got back to you. One other thing to check is the radiator valves. In the past I have found rad. valves with cracked and deteriorated disk material ( disk is what closes against the valve seat ) what was happening was the valve was allowing steam into the radiator but not allowing condensate to drain back. to check, shut off steam supply , disconnect the union on the valve, move the radiator and inspect the valve disc and seat. the problem can also occur if the tenants are trying to use the valves as a proportional control, rad. valves must remain all the way open on 1 pipe systems. the tenants must be aware if they shut off a radiator. when the radiator is turned back on ( valve opened again ) there will be air and water in the radiator, you can expect banging and some spirting of air vent until water is allowed to drain back to system.
@ December 24, 2012 3:12 PM in help with measuring airflowGo with a smaller range magnahelic, like a 0-.25 or 0-.5 remember if you think your looking for under 500 cfm your 2 inch mag is to big. also are you measuring free area, if there is a grate, register or diffuser in the air stream you need to account for that, make a number of cross section readings and get an average reading. In some cases registers etc can account for a 50% reduction in air flow readings. There are also air flow meters you can attach to your volt/amp meter, field peice makes a good one. the Trane air conditioning manual has a excellent chapter on air flow
@ December 24, 2012 11:38 AM in MERRY CHRISTMASMerry Christmas to you and your family Steve
@ December 23, 2012 2:34 PM in gas lines to boiler and other appliancesthe outlet press. for natural gas from most gas co. regulators is usually about 1/4 psig (7 inches water column w.c.) regardless of the inlet press. outlet press. over 1/2 psig can damage most diaphram gas valves
@ December 23, 2012 11:30 AM in fluctuating draft with power vent + power gaswhat about that single wall flue pipe ?
@ December 22, 2012 10:23 PM in thankyou fan in a can.....have been using this fan on my commercial jobs for years in some cases i have 2 . some basements just dont have enough space for gravity fed ducts for combustion/fresh air Field controls also makes a good barometric damper
@ December 22, 2012 8:54 PM in gas lines to boiler and other appliancesDont confuse psi with inches of water column ( w.c.) most residential and small commercial bldgs have low press. gas service to the bldg regulator ( 14 inches or 1/2 a pound ) 5 psi could be considered medium press. gas, you could have med press. you should contact your gas co. to get this info and have them sign off on this piping, looks a little sketchy to me.
@ December 22, 2012 11:21 AM in suppemental heatAs I stated carrier and other manufacts. use this cfm data. I Installed , started up and serviced hvacr euip. for 38 yrs I agree for system design do a heat load, but in alot of cases when your on the job not in the office this rule of thumb gets you to a starting point. I came from your fathers day when a service man was expected to know all phases of this trade, Lets appreciate what we have taught the younger guys, without them this trade would be in trouble
@ December 22, 2012 10:44 AM in need help reading the pressure gaugeI agree with Bob should be repiped in blk pipe with cast iron fittings to allow pipe movement ( see swing joints ) the way it is now there will be pressure against the boiler sections causing problems
@ December 21, 2012 2:29 PM in Gas meterGo on yahoo look up clocking a gas meter good stuff
@ December 21, 2012 11:32 AM in LWCO CloggedLwco's need to be blown down weekly per most manufact. ( Mcdonnell Miller ). Strainer basket assy should be cleaned or replaced at least twice a year if not more often. Once a year I will completely take apart lwco and clean out bowl and flush out blow down valve.
@ December 20, 2012 10:42 AM in auto feed system - necessary?Many cities require redundant low water cutoffs on commercial boilers one of them being a lwco feed valve combination. ex. ( mcdonnell miller # 51 ). Yes a boiler could dry fire if any lwco is neglected. Mc Miller recommends blowing down the lwco weekly. I found when doing boiler P/M 's that if customer could do it themselves every 2 wks that was good. I would clean or replace the strainer basket every 3 months and completely clean entire unit yearly especially the bowl float assy.
@ December 19, 2012 8:35 PM in Merry ChristmasMerry Christmas to all remember John 3:16
@ December 19, 2012 8:28 PM in What watt!My understanding is that (power factor correction ) is not used in resistive loads, In a 3 phase suppl. heater circut we add the following amps = KW x 1000 divided by volts x 1.73. On page 17 of the Ugly's book I believe they are talking about inductive, reactive loads. (motors , transformers ) I always like to get several sets of eyes on all questions.
@ December 19, 2012 11:23 AM in Tips to repair Car Air ConditionersDont forget to change the cabin filter It is fairly simple to get to on newer cars. there are some good videos on you tube
@ December 18, 2012 3:12 PM in Dual Duct VAV boxes - Inlet PressureContact your local Trane rep. ask for literature and request a I.O.M. (manual) also on yahoo look up HVAC units-Varitrane dual duct boxes. you will need some training on this one. may need Rover/comm 4 software and Rover tool
@ December 17, 2012 2:26 PM in furnace firing issueYou need a minimum of 5 inches water column to inlet of most gas valves and 3.5 inches to burner on most furnaces, these setting can change if you have a 2 stage valve and on commercial burners. most diaphram style gas valves depend on this 5inch to 3.5 inch pressure drop to operate correctly.