HVAC

Have HVAC Questions? Ask an HVAC Expert for Answers

Ask an Expert,
Get an Answer ASAP!

HVAC

I have an older AO HW200 M 890 series (standing pilot) that…

Customer Question
I have an older...

I have an older AO Smith HW200 M 890 series (standing pilot) that we cannot hold the pilot. The t'couple puts out over 30 mv. If we jump out the wires going to the protector switch sometimes it works sometimes it doesn't. We have cleaned the pilot, replaced the t'couple, replaced the gas valve and still does not remain working on a consistent basis. Do you have any advice? I am uncertain on how to properly diagnose the operation of the t'couple and the wiring to and from the protector switch. Any input?

Contractor's Assistant: I'll do all I can to help. How long have you been dealing with this?

Over a week

Contractor's Assistant: Do you plan on doing the work yourself?

Yes either myself or one of my technicians, I am the service manager for a commercial sized mechanical contractor. I have looked at this along with two other technicians. As soon as we think we made progress something different occurs.

Contractor's Assistant: Anything else we should know to help you best?

As it stands now, we removed the replacement gas valve because it wouldn't hold the pilot at any time and re-installed the original valve with a typical t'couple. (no connections for protector switch). It ran overnight that way. This is supplying HW for an apartment complex.

Submitted: 2 months ago.Category: HVAC
Show More
Show Less
Ask Your Own HVAC Question
Answered in 32 minutes by:
12/14/2017
HVAC Technician: airheatman, HVAC Technician replied 2 months ago
airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8,908
Experience: Furnace, A/C and heat pump specialist.
Verified

Most of these protector switches were manually reset. Do you have an auto reset switch?

Ask Your Own HVAC Question
Customer reply replied 2 months ago
No, it is manual reset and has not tripped. Continuity test shows closed.
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

OK that is what I thought.So since it is not tripping and the fact you jumped it did not completely solve, we can pretty much rule the protector switch out as being our culprit.

Since we are having the same issue with two different gas valves, that sort of leads us to doubt the valve is the issue.

THis leaves the thermocouple and gas pressure as I don't see any other components on the standing pilot, correct?

Have you actually tried replacing , not just cleaning the thermocouple?

Ask Your Own HVAC Question
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

OK just re read and see you cleaned pilot and replaced thermocouple

Ask Your Own HVAC Question
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

Are there any other components on this heater other than what we I just mentioned. (Gas valve,protector switch,pilot and thermocouple)?

Ask Your Own HVAC Question
Customer reply replied 2 months ago
No sir
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

OK it appears you have tested everything and under ideal circumstances everything works.

This means something has to be changing that is causing us to lose pilot.

The two most common external issues are gas pressure supply and wind.

Does there seem to be anything of significance that is changing when it goes off? (high winds outside, extremely low freezing outdoor temps,opening and closing door in location of water heater that could create a draft,high usage of other gas appliances such as furnace)?

Ask Your Own HVAC Question
Customer reply replied 2 months ago
I am sorry none of those suggests apply. This is why it is so baffling to me. I wonder if you can answer this question. When I read the output of the t'couple from the terminal closest to the pilot to ground I read 30 mv. With a jumper across the terminals and I read from the other terminal (closest to the gas valve) to ground, I read 2 mv. Does this tell you anything?
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

THat really doesn't tell me anything.I have never had any reason to put a jumper across them in troubleshooting.

Have you ever been able to get to "NOT relight" and have the 30mv at valve or when we have the 30mv does it always light then just go back out later?

Ask Your Own HVAC Question
Customer reply replied 2 months ago
We have always been able to relight the pilot. The thermocouple has always produced the 30 mv but the pilot has not always been held on once the gas valve knob has been released. It may work for awhile but then fails. For instance, it worked from 3:00pm-6:00pm. Relit at 6:00pm and would not hold, relit again (second try) and held to 9:00am the following morning.
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

I would try another valve but if original does not have the witch, use one that does not

Ask Your Own HVAC Question
Customer reply replied 2 months ago
I do not understand your response
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

You stated original gas valve did not have the place to connect the protector switch yes?

Ask Your Own HVAC Question
Customer reply replied 2 months ago
No I did not say that. The protector switch attaches to the thermocouple anyways not the gas valve. We have not altered the situation from what it was originally, only replaced components with what was there. I feel you are in the same position as I was before we conversed. Guessing that it is a gas valve issue even though it is a new gas valve. Agree? I suppose we could have caught a bad valve.
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

I understand. In your original post you stated " re-installed the original valve with a typical t'couple. (no connections for protector switch)." is why I thought you had made a change.

Lets try a new valve and see .It is possible you got a bad one .

The only other thing I could imagine would be a venting issue letting downdraft blow out the pilot.

Ask Your Own HVAC Question
Customer reply replied 2 months ago
Down draft is not the issue. We can watch a perfectly good pilot flame drop immediately out when releasing the gas valve knob.
Can this conversation be picked up at a later date because our local supplier does not have another valve in stock, has to be ordered?
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

Absolutely.Just come back to the question any time

Ask Your Own HVAC Question
Customer reply replied 2 months ago
Thank you!
HVAC Technician: airheatman, HVAC Technician replied 2 months ago

Good luck,Hope the valve solves

Ask Your Own HVAC Question
Ask Phil Your Own Question
Phil
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6,938
6,938 Satisfied Customers
Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial

Phil is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future.

JimmyBagley, IA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

Phil

Phil

Mechanical Engineer

6,938 satisfied customers

Retired HVAC/ Electrical & Boiler contractor. Industrial

Rick Mather

Rick Mather

HVAC Technician

3,133 satisfied customers

35 years experience, HVAC

Matthew

Matthew

HVAC Technician

2,014 satisfied customers

14 years experience in the HVAC field of service, installation, Manual J & D calculations

Kenton Guidry

Kenton Guidry

HVAC Technician

963 satisfied customers

12 years install/service experience.

Brian HVAC Guy

Brian HVAC Guy

HVAC Technician

953 satisfied customers

I have been an HVAC/R mechanic/technician for 30+ years.

Rick Ridley

Rick Ridley

UK Heating Engineer

871 satisfied customers

Retired But have had 30 years on the tools, Ex CORGI

Tom

Tom

HVAC Technician

770 satisfied customers

16+yrs HVAC/R service. Residential Commerical Industrial

< Previous | Next >

Related HVAC Questions
We are trying to convert a newAO 30 Hallam water heater to
We are trying to convert a newAO 30 Hallam water heater to propane. We can not get the manifold tube out. We are trying to use a 3/4 wrench unscrew it going right as the instructions state. It will no… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I have a Richmond 6G50 water heater. It was in a flood and
I have a Richmond 6G50 water heater. It was in a flood and water got into the unit. About 4 inches. Inwas able to shop vac all water that was between metal frame (only like .5 inch got in there) now t… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I have a Bradford defender water heater with a Honeywell
I have a Bradford defender water heater with a Honeywell controller. It does not have a reset button and the pilot light is off … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
Tank less water heater is flashing (14) Then I pushed the
tank less water heater is flashing (14) Then I pushed the both temp. buttons (up & down) and then it blinked 1 E … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
We have a small water heater nmounted under the sink. Itis
We have a small water heater nmounted under the sink. Itis new. it has a green wire, a brown wire and yelow/green striped wire. … read more
Gaztech
Gaztech
Technician
Vocational, Technical or Trade School
1,142 satisfied customers
I have a grundfos pump attached to my water heater in my
Hi, I have a grundfos pump attached to my water heater in my home. Lately it has been making loud noises and vibrating loudly. I would like to disconnect the pump and let the water heater run on its o… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
My electric hot water heater isnt working. My electric hot
my electric hot water heater isnt working. i've tried to reset the breaker several times with no success. Is there a failsafe breaker on the water heater itself. the unit seems fairly new … read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
We have a tankless water heater that was installed in our
we have a tankless water heater that was installed in our new house this last summer. Often, when it turns on it makes a noise kind of like JAWS approaching, that slowing gets louder and faster until … read more
WCohn
WCohn
Journeyman Plumber
Journeyman License
1,437 satisfied customers
I HAVE A RUDD GAS WATER HEATER MODEL P500V. IT IS LEAKING
YES - WHAT RUDD WATER HEATER WILL REPLACE THE P500V… read more
Charles
Charles
HVAC Technician
Associate Degree
91 satisfied customers
I HAVE A pOLOPA TANKLESS GAS WATER HEATER AND IT KEEPS GOING
i HAVE A pOLOPA TANKLESS GAS WATER HEATER AND IT KEEPS GOING OFF WHILE running hot water and thermstat reads C8 … read more
canuck the pro
canuck the pro
251 satisfied customers
We have a Buderus boiler and water heater (ST 150) that was
We have a Buderus boiler and water heater (ST 150) that was installed in 2006 before we bought our home. The maintenance tech came out today for annual maintenance and he told us we need a new water h… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I installed a Reliance 19.9 gallon water heater in a
I installed a Reliance 19.9 gallon water heater in a friend's mobil home today. The supply lines come into the tank from the side. There is a blue plastic lining material in each 3/4" nipple (cold inl… read more
Phil
Phil
Mechanical Engineer
6,938 satisfied customers
I changed the thermocouple on my water heater but the pilot
I changed the thermocouple on my water heater but the pilot will not stay lit … read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
My tankless water heater will not run, breaker not tripped
My tankless water heater will not run, breaker not tripped and when I push sw1 or sw2 it starts running while pressed in. What is my problem? … read more
Phil
Phil
Mechanical Engineer
6,938 satisfied customers
I have a water heater question! I have a RTE-13 water heater
I have a RTE-13 water heater where the reset button keeps popping. It has been going on for a week now … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
Its the thermostat on my water heater... it seems stuck and
Its the thermostat on my water heater... it seems stuck and wont turn to the off position … read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I have a Rheem Marathon water heater that is not producing
I have a Rheem Marathon water heater that is not producing hot water..., any suggestions ? I have power going to both the top and bottom elements. I have tried to push the reset button but it will not… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
If a gas water heater with an FVIR is installed in a room
If a gas water heater with an FVIR is installed in a room with a washing machine, can cleaning products such as liquid laundry detergent and chlorine bleach trip the FVIR? … read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x