Joined on July 1, 2010
Last Post on March 3, 2014
@ March 3, 2014 12:32 PM in furnace problemI have a Nordyne furnace and the service tech recently replaced a limit switch set at 225 degrees ( the old one was set at 205 degrees). I have a variable speed fan motor on a 72,00 btu furnace and the cfm setting was on 1050. The tech said he had raised that to the next level (which I believe was 1200 cfm). After several weeks I found the house to be quite dry and uncomfortable. I tinkered with the switches below and attempted to return it back to its original setting but I mistakenly set it higher (1500 cfm).
After more discomfort I went down and realized what I had done and reset it at the original 1050 cfm. I also changed the air filter which was understandably pretty dirty.
Now I'm not sure if it's just me or something is not right. Everything seems to be working but the fan speed sounds noisier and the dry and discomfort remains. Is it possible that something needs to be reset? I have turned the burner switch on and off, as well as the thermostat. With the weather changing so much ( dramatic rise and fall of outdoor temps recently) it's hard to judge if the forced air heat is working as it was in the past.
I'm trying to avoid another charge/call to the furnace contractor.
Thanks for any suggestions!
@ October 28, 2013 8:21 PM in a question on EDRThank you for clarifying that for me. That explanation clearly brings to light how powerful the thermal energy of steam is.
@ October 27, 2013 8:23 PM in a question on EDRThat's the thing that's haunting me. We know that it takes 180 btus to get a pound of water from 32 degrees F to 212 degrees F and it takes 970 btus for that same amount of water to become steam.
If 1 edr is equal to 240 btus for steam does it mean when it's condensing and releasing all of its heat energy? Is there a different amount of btus for water @ 212 degrees F?
Not looking to do anything with this in regards to a hw or steam system, just trying to clarify the science.
@ October 26, 2013 11:15 AM in a question on EDRAs I understand it 1 EDR is the equivalent of 240 BTU's per square ft. of radiation when there is 215 degrees F of steam and 70 degrees of air outside the rad.
With hot water radiation you should get about 170 BTU's per sq. ft. when the water temp. is 180 degrees.
The question I have is related to the latent heat of vaporization. If you have 215 degrees of water ( pressurized, of course) in a radiator, how many BTU's would be released per sq. ft. of radiation?
Would it be the same 240? Shouldn't be less due to the fact that you are not releasing latent heat? If so, how many BTU's per EDR?
Looking to clarify the whole EDR thing at that boiling point temperature regardless of pressure, if that makes any sense.
@ October 20, 2013 7:41 PM in firing rate of he boiler?Thanks NBC!,
When you mention vaporstat are you refering to a vapor system only? Will other steam boilers use a pressuretrol to control the firing rate? How about HW boilers, are they controlled by an aquastat and thermostat?
@ October 19, 2013 10:13 AM in firing rate of he boiler?Looking over old notes from a seminar and trying to answer the questions regarding boiler firing rates, I'm struggling to get things clear in my head.
When dealing with hw boilers and steam boilers, what device or devices control the firing rate? Is it the thermostat, a timer or an outdoor reset control? Is it a combination of different controls? Are there choices according to the contractor or engineer?
Trying to answer the questions of over-firing and under-firing. And its connection to the common problem of short-cycling. As I look through my old dead men's school workbook the troubleshooting answer to certain issues says: the burner isn't firing to the connected load. I think I know what that means, but how does one go about fixing that problem. Is it just a control problem if the boiler is sized correctly?
@ October 12, 2013 2:05 PM in Steam Boiler CleanerI don't have experience cleaning boiler water but I thought I might mention two items from Holohan's books. One is that a cleaner called MEX ( a newer, safer cleaner similar to TSP, tri-sodium phosphate) has had claims of doing a fine job at cleaning water in a steam boiler. The other is that skimming and other methods requires patience and persistence that most contractors lack because, after all, time is money. A good cleaning job, in regards to skimming may take an entire day.
@ October 12, 2013 1:11 PM in Help With RadiatorsThere are fittings called " extension couplings" that may give you the height that you need. You would have to very carefully remove the radiator valves and traps and add these couplings( which are nothing but a coupling that is male X female as opposed to the standard female X female couplings) before re-installing the valvea and traps.
It is important to consider the branch piping below and access to them in case a problem should occur and re-piping has to be done.
I would be careful in cutting rad legs as cast iron can break and you may end up replacing a radiator. If ext. couplings don't give you the right fit I would consider standard couplings with close nipples and shimming up the radiator to the new height.
Hope this helps!
@ October 7, 2013 9:50 PM in boiler firing ratesWhat determines the firing rate of a boiler? Is it by design of the system? Is it something that's pre-determined by the boiler manufacturer? or is it strictly determined by controls like thermostats, aquastats and outdoor reset controls?
@ October 6, 2013 6:29 PM in consultation on old steam system eastern connecticut areaIs the main steam vent working properly?
A counterflow system has limitations on how long the main can be run due to the fact that you need pitch back to the boiler.( 1" per 20 ft.). Sounds like it may be too long a run. Did the radiators work properly before? If there is a condensate return at the end of the main then the pitch should go towards it and that would make it a parallel system.
In either case, I would check the main air vent. Is the main getting hot all the way through? If it is then check the radiator vents as well as the rads pitch back to the rad valves.
@ October 4, 2013 6:22 PM in tankless coil in the winterI'm guessing the mixing valve is electric. What type of controls? Does the control get wired to an aquastat that is seperate from the aquastat that controls the boiler for hw heating?
Are there mixing valves that are non-electric?
@ October 3, 2013 10:07 PM in firetube vs. watertube boilersIs it easier to maintain a firetube boiler as opposed to a watertube boiler?
Which one requires more off-season maintenance?
@ October 1, 2013 9:59 PM in tankless coil in the winterHow does a tankless coil operate in the heating season? While a hot water boiler is heating at, let's say 180 degrees, what prevents the domestic hot water from overheating?
Are there different scenarios depending on storage tanks?
@ July 22, 2013 8:07 PM in circulators/pumpsThanks for the info. very helpful!
I'm glad you mentioned velocity, because i'm still trying to wrap my head around the whole velocity thing. feet per second, milinches, gpm.
If gpm represents flow rate and feet per second represents velocity, what is their relationship?
If larger pipe gives you slower velocity, how do you maintain a set gpm on a given pump/circulator? If the water is moving slower wouldn't it circulate less gallons per minute?
Studying pumps and hw systems, but still getting hung up on a few items.
I appreciate your help!
@ July 22, 2013 7:54 PM in circulators/pumpsThank you kindly. I can understand the reason for larger inlets better as you explain the fact that there is less resistance due to the larger outlet. "Easier to push than pull," is a great way to think about the function as well as remembering the concept. Thanks again!
@ July 21, 2013 8:15 PM in Copper prices affected by Bank manipulation of MarketsI read that article this morning and was amazed what the banks and large finacial firms like goldman sacks were able to do with the storage of aluminum.
This is another loophole in financial laws that needs to be regulated. The big banking and finance industry strikes again, making more money in a struggling economy as the businesses, their workers and customers of these metals pay unnecessary price increases.
What a shame!
@ July 21, 2013 8:03 PM in circulators/pumpsSorry guys- got that last post backwards. As you know the outlets are smaller than the inlets.
Looking for an explanation of the pumps with same size inlet and outlet. How do they work?
@ July 21, 2013 8:00 PM in circulators/pumpsThe literature and study materials regarding centrifugal pumps state that the inlet is usually smaller than the outlet. The pump/circulator causes a pressure differential and provides flow in the piping.
How does the circulation work on pumps that have the same size inlet and outlet?
If i'm not mistaken I believe there are small circulators as well as pretty large ones with inlets and outlets of the same size. Is the inside of the pump different than the other pumps with different size outlets?
@ July 20, 2013 12:31 PM in steel compression tanks collapsing?Curious!
I read about this happening, but I'm curious if anyone has a real life story about a steel compression tank collapsing and possibly any pictures.
@ July 20, 2013 11:53 AM in A question of design (circuit setters)I am currently working on a large project as an installer with limited acces to design drawings of a 3-pipe hw/chilled water system using fan coil units in apartments (3rd pipe is cond. drain).
The buildings are 21 stories high with approx. 20 sets of risers ( each riser feeding one unit per floor). Each trane unit has a circuit setter on the return and shut-off valves on both supply & return)
The supply & return mains are 6 inch and supply chilled water in the summer and hot water in the winter from a central plant. The return riser runouts have a circuit setter.
The mains on the ground floor are run in reverse as a reverse return system. However, the risers (which were originally run as a reverse return when the building was built 50 years ago) are presently being run as a direct return system. So the 1st floor is now returned first as opposed to its original layout which had them returning last. There used to be a return main on the 21st floor which tied into a dead riser down to the first floor.
So my question is this:
For water balancing purposes, can this new modified system work properly and be balanced as the previous system was? Are the circuit setters on each return risers capable of doing the job without a reverse return riser set-up?
This new renovated system obviously saves money on installation due to the labor and material saving of a 6 inch riser and main on the top floor, but will it be easy to balance? Are the circuit setters capable of doing the balancing?
Thanks guys for any comments!
@ July 7, 2013 3:52 PM in control valves: supply or returnOn large commercial hw systems I have seen control valves on either supply or return of heat transfer units.
On hw re-heat coils in the ductwork the cv's seem to favor the return, but on fintube baseboard I usually see them on the supply. What is the primary reason for the cv location on hydronic heating systems?
Do engineers differ in opinion on whether it is beneficial to locate the cv on the supply or return? Are there other reasons for the placement of cv's?