View Full Version : Installation Basic Matters
01-27-2004, 08:07 PM
As a Neophyte around I'd like to ask to the expertise some words of advice (in plain english) regarding the following :
(Even when the installation technician may have the all answers, I want to get the info)
- Dryers Make up air ; how is it calculated and what's the best (cheapest-safest) way to create it in a store ?
- When vibration is an issue , what's the best way to minimize it ?
- Any considerations about dryers exhaust ? Like ducts, filters,ducts run, Are there enviroment issues involved ?
- How can we calculate the gas or electricity estimated comsuption for any individual machine ( Dryer or washer) from the specs sheet?
Thx in advance to every one.
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01-28-2004, 01:43 AM
Anyone with Help ?? !! You can also PM . Thx
01-28-2004, 04:19 PM
Dryer makeup air is calculated by knowing the CFM of exhaust air the dryer puts out. This figure will also be affected (reduced) by the length of the duct, the number of elbows/turns and the size of the duct. You need as much makeup air as is being exhausted by each unit.
To be able to actually figure this you need the dryer specs at a specified duct static pressure (the presure created by the fan) measured in inches of water column. You will then need a chart that gives you the CFM of air flow at a specific static pressures per 100 equivalent feet of duct. This sounds like a lot of duct, but one long-turn elbow is equivalent to 15 feet of straight pipe and a short-turn elbow is twice that (30 feet).
The more freely the exhaust air can escape the better, faster and more efficiently the dryer the will work. Never, ever, ever install filters in the dryer exhaust air stream, as they will plug very quickly and prevent the dryers from working properly and are a fire hazard.
Makeup air is calculated (roughly) by installing a grille in an outside wall that will flow as much air at maximum as the dryers will exhaust when all the dryers are running. I don't have any charts handy, but this is calculated by using a maximum pressure differential across the grille of approximately 1/10 - 1/4 inch water column, and determining how many CFMs this will provide. Every grille mfg will have these specs. In general, if all the dryers are running and inswinging doors don't close properly or out swinging doors are hard to open then you don't have enough make-up air.
I'm not an expert on vibration, but in general, it is either caused by something being out of balance or not being properly installed/mounted. All four legs need to have approximately the same loading, etc.
By the way, don't ever used sheet metal screws through the duct to secure dryer exhaust duct. This violates code and creates a fire hazard by catching lint on the inside of the duct. Use external connectors or usually aluminum foil tape to secure round duct sections.
Gas and electric consumption are easy.
Amps (always given on any machine) X volts = watts
1000 watts = 1 kilowatt, and 1000 watts of consumption for one hour = 1 kWh (kilowatt hour) which is what the power company bills you for.
Gas consumption will be given as BTU of input. 100,000 BTU = 1 therm, which is how most utilities bill for gas. On occasion you may be billed for cubic feet of gas, in which case 1 cubic foot of gas is app = to 1,030 BTU. (The actual BTU varies depending on energy content of the gas and time of year). The advantage of being billed in therms is that this figure is always corrected to exactly 100,000 BTU by the gas company.
Hope this helps.
01-30-2004, 01:31 AM
Thx KM for your insights and helpful info.
01-30-2004, 11:38 PM
Dryer vibration is usually caused by a out of balance fan, bad motor mounts, or a cracked drive belt.
Front loader vibration is generally caused by an insufficient foundation. I have also found that using machinery grout will spread the load over the entire frame and will help reduce vibration.
The installation information should be included when you buy the washer or dryer.
American Dryer has an excellent manual on exhaust and make-up air for dryers. It can be used for all makes of dryers and is a great reference tool.
02-03-2004, 02:15 PM
Thx RW. Thoughts kindly appreciated.