When applying in call center, if they ask you the following questions What is the best possible answers?? 1.Tell me something about yourself? 2.Why do want to work in this company? 3. How you would be an asset to the organization? 4.Why should we hire you? 5.What is your greater strength? 6. What is your philosophy towards work?

Seems a question with many possible answers.
1) Are you asking if you should thread the pipe?
2) What size pipe?
3) Threads on copper, not normal, not possible in most cases.
4) Thread Plastic? Only if it is Schedule 80 or above.
5) Thread metal. Assuming galvanized or black iron, this would be normal.

I need a lot more detail to intelligently answer the question.

Gary C

What product is making beeping sound?
Repost question and choose best category and give as much info as possible, and then fixya might truncate question so we cannot see what was asked

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Copy following link for error 11 troubleshoot from 2009 service manual that may or may not apply to your model. Otherwise there are no service manuals.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/How-to-install-gas-water-heater.html

2) Least expensive, and most certain repair for tankless is to install tank-type heater from local box store.
http://waterheatertimer.org/pdf/Which-is-best-gas-water-heater.pdf

3) Replace PC board is one possible solution.

4) Add comment and say what you discover

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

You posted 2 questions.
Add a comment to clarify problem
One question says black wire is sparking is inside water heater, and this question says black wire is sparking inside the panel and is posted under WH40 water heater timer.

If wire is sparking, then it is not attached firmly, or wire is not attached correctly, or there may be too many amps drawn across the terminal.
WH40 has 40 amp terminals and will handle all residential water heaters.

Open following links for instruction how to avoid sparking, and avoid fires inside timer:
http://waterheatertimer.org/How-to-troubleshoot-Intermatic-timer.html#fire
Open following link to see how to apply wire nut:
http://waterheatertimer.org/How-to-twist-electric-wire.html

Question is not clear.
Do you want instructions to replace valve or want a service manual to test out the parts?
Open following link to help identify gas valve and download possible service manual that applies to that gas valve.
http://waterheatertimer.org/How-to-adjust-temperature-on-water-heater.html#intelli

It is usually recommended that a professionally trained person replace the gas valve.
If you have the intellivent gas valve, then it usually has identifying marks on side of valve, or call AO Smith with the model and serial number from label on side of tank.
Turn off gas and disconnect gas line from side of valve.
The manifold tube and wires are disconnected.
The gas valve unscrews counterclockwise.
If you want more details as the project requires, add a comment with specifics and that sends email that I will answer.

Questions might be asking for a manual, and asks what error A7 means, and asks how to fix error problem, but model number of Bosch heater is not given.
Error codes are start-point for troubleshooting, and can include multiple causes.
So following answer provides general do-it-yourself resources, without saying that problem can be 100% diagnosed or fixed by homeowner.

1) Error code A7 is outlet temperature sensor fault.
Problems include: need for descaling, dirty inlet water filter, debris in faucet aerators, dirty wiring terminals, bad wiring harness, or bad temperature sensor.
http://waterheatertimer.org/pdf/Bosch-GWH2400ES-error-codes.pdf

2) Before calling service technician who can test failed parts and catch tankless up on yearly maintenance, open following links for Bosch resources including error codes, phone number, possible manual, and descaling instructions, and cleaning inlet filter:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
http://waterheatertimer.org/pdf/Rheem-De-lime-tankless.pdf
http://www.boschhotwater.com/Portals/7/TechBulletins/TWH-G1-12_Cleaning_inlet_filter.pdf

3) Product manual: Question posted under model 125HX-LP
Open following link for possible manual:
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/125HXTechSupport/InstallationManuals/tabid/542/Default.aspx

4) Do it yourself service bullitens for 125HX-LP
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/125HXTechSupport/ServiceBulletins/tabid/548/Default.aspx

5) Take a moment and rate answer:
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Question posted under water heaters, but no brand or model number is given.
Question asks for product manual. And asks for interpretation of error code.

1) Look on side of water heater for machine information, and then add a comment and include all possible detail for best result, including brand and model number, and approximate age of machine, and whether machine is gas or electric powered.
Adding a comment with specific information will tell expert what answer to give, or expert might not be expert in your product and will suggest that new question be re-posted at fixya for another expert.

2) To find a product manual on your own, Google search model number of machine, and add the specific words to search parameter: instruction .pdf
For example search for: Rheem Pro40NE2 instruction .pdf

Resourceful do-it-yourselfer can add a comment with type, make and model number of product for best answer.

1) Open following link if you have electric tank-type water heater, for tested, full service do-it-yourself diagnosis.
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html
Open top cover and push in ECO reset button:
http://waterheatertimer.org/images/Jly-022-thermostat2-175.jpg
Find age of water heater using serial number located on label on side of tank:
http://waterheatertimer.org/pdf/WaterHeaterSerialNumberDecoder.pdf

2) If you have tank-type gas water heater, thermostat is connected to gas valve, but you might have question about gas flame instead of thermostat.
Check manual, check flame, buy new gas valve at local home center.
Following link shows typical gas valve with brass thermostat:
http://waterheatertimer.org/images/316938_603.jpg

3) If you have tankless electric or gas, the problem can be varied from internal to external causes.
Check manual, call service technician.

Add a comment for more free help.
Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

I cannot find information on SRM water heater in my files or on the internet

1) Add a comment and say what brand and type of water heater that you have so expert can identify specifics and give you best possible answer.
This information is located on the water heater label, and then add a comment.

If you do not have time to add a comment with description, there are other resources:
2) Open following link and see it it applies to your type of heater:
http://waterheatertimer.org/How-to-adjust-water-heater-temperature.html

3) Search following list for your manufacturer, and then order manual:
http://waterheatertimer.org/Water-heater-manufacturers.html

4) Look at product manual that came with water heater, or call installer.

5) Call local plumber

Add a comment for more free help.
Also take advantage of fixya expert assistance live.
For a price, expert works with you via e-mail while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

1) Rheem does not show that exact model number, since they list current products only.
http://www.rheem.com/products/tank_water_heaters/gas_water_heaters

2) Rheem serial number shows year of manufacture on second 2 digits. So C06 was made in 2006.
Today's manual might not have troubleshoot steps that match older product.

3) 21vp50 is 50 gallon power vent water heater.
Open following link to identify product.
New models have Honeywell electronic gas valve with LCD flashing error codes.
http://www.rheem.com/product.aspx?id=C24E3F52-A6A4-4BC7-AF5B-0DF23A7A0263
http://waterheatertimer.org/gas-water-heater-timers.html#Rheem

4) Sample manual for newer power vent models shows error codes and troubleshoot steps:
http://globalimageserver.com/fetchDocument.aspx?id=a92c7d0e-8a95-48ba-8810-cd714f33d47a

5) Earlier Fixya answer suggests where to buy ignitor for 21vp50:
PART #HSI51409A
http://www.fixya.com/support/t3641891-rheem_21vp50_1_igniter_stopped

6) Your manual should show troubleshoot steps and expanded parts list.
Always save manuals like gold, and save searching later for a manual at Fixya.
If we can't find the manual, then our answers are limited to suggestions and guesses, since we're not on-site and can't perform troubleshoot steps for you.

7) Post your question on professional water heater forum
http://www.thetankatwaterheaterrescue.com/forums/forum3/

8) Call Rheem and they can possibly suggest which local service technician will work on that model:
2600 Gunter Park Drive East
Montgomery, Alabama 36109-1413
Phone: 1-800-432-8373.

9) Call a local plumber.

10) Install inexpensive home-center brand gas water heater yourself:
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.