HVAC

Have HVAC questions? Ask an HVAC Expert for answers

Ask an Expert,
Get an Answer ASAP!

I am trying to connect a Honeywell RTHL3550 thermostat. My…

Customer Question
I am trying to...

I am trying to connect a Honeywell RTHL3550 thermostat. My old thermostat has only 3 wires, white, red, & green. How do I connect to new thermostat?

Contractor's Assistant: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?

Thermostat

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

Yes

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

Not that I know

Submitted: 10 months ago.Category: HVAC
Show More
Show Less
Ask Your Own HVAC Question
Customer reply replied 10 months ago
It is strictly hot water heat. no heat pump, no a/c
Answered in 40 minutes by:
10/4/2017
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago
gotoman for ac
gotoman for ac, HVAC Technician
Category: HVAC
Satisfied Customers: 5,357
Experience: 51 years of experience install design and repair of all makes and models of AC
Verified

Russ here one moment while I pull manual. Russ

Ask Your Own HVAC Question
Customer reply replied 10 months ago
Illustration on page 5, para 6 shows 4 wires green white yellow red.
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

Can you attach photo and wiring of old thermostat. Russ

Ask Your Own HVAC Question
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

Where were wires attached on old thermostat. Trying to make sure this on will work. Russ

Ask Your Own HVAC Question
Customer reply replied 10 months ago
I don't remember where the wires were connected on the old mercury type thermostat.
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

Did the old system operate a valve or a hot water pump. Russ

Ask Your Own HVAC Question
Customer reply replied 10 months ago
Probably the hot water pump. No sure.
Customer reply replied 10 months ago
Actually not sure if a valve or water pump.
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

These are small thermostat wires correct. If it is just operation a pump on and off you would go with R and W. Red to White to W. If it was driving open and close a valve you would need a different thermostat. Russ

Ask Your Own HVAC Question
Customer reply replied 10 months ago
Any idea what the green wire would be for?
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

That makes me think that it is operating a valve that drives open and drives closed. The thermostat you need is Honeywell 5110D. Works on hydronic valves opens and closes. No where in your literature does it say it will operate heating valve. Russ

Ask Your Own HVAC Question
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

The one you have will drive it open but not closed. Russ

Ask Your Own HVAC Question
Customer reply replied 10 months ago
OK thanks Russ.
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

You are quite welcome. Glad to see someone who ask the right questions. Open for rating thanks. Russ

Ask Your Own HVAC Question
HVAC Technician: gotoman for ac, HVAC Technician replied 10 months ago

Anymore questions please get back with me. Russ

Ask Your Own HVAC Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a hvac technicianLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask gotoman for ac Your Own Question
gotoman for ac
gotoman for ac
gotoman for ac, HVAC Technician
Category: HVAC
Satisfied Customers: 5,357
5,357 Satisfied Customers
Experience: 51 years of experience install design and repair of all makes and models of AC

gotoman for ac 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

7,634 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

Brian HVAC Guy

Brian HVAC Guy

HVAC Technician

1,024 satisfied customers

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

Kenton Guidry

Kenton Guidry

HVAC Technician

963 satisfied customers

12 years install/service experience.

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
Is available??? I have a trane baystat 240...want to changer
I have a trane baystat 240...want to changer out to a honeywell rthl3550... … read more
Michael Ferryman
Michael Ferryman
110 satisfied customers
Wow that impressive, i have a trans heat pump and I'm trying
i have a trans heat pump and I'm trying to connect the honeywell rth9580wf to it. it only has two wires … read more
Billy
Billy
Journeyman Service Technician
State Licensed Mechanical Contractor
9,330 satisfied customers
Help... trying to replace a trane weathertron with a
help... trying to replace a trane weathertron with a honeywell the trane is a baystat240a to a honeywell LR69071.… read more
Airheatman
Airheatman
Heating & Air Conditioning Contractor
6 years college
1,836 satisfied customers
I am replacing the old Rodgers with a Honeywell RTH6500
I am replacing the old White Rodgers with a Honeywell RTH6500 Wi-Fi. The old one does not have a C wire. I connect the existing B wire to C terminal and the O wire to O/B and the rest of the wires as … read more
Billy
Billy
Journeyman Service Technician
State Licensed Mechanical Contractor
9,330 satisfied customers
I'm trying to replace a ta2000 thermostat with a Honeywell
Hello! I'm trying to replace a ta2000 thermostat with a Honeywell rthl3550. The ta2000 has L,B,W2,O,R,Y,G,E,W3. The wires connected to them were as follow. Blue wire to b, white wire to w2 (with a jum… read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
We just installed this Honeywell CT87N and can only get hot
We just installed this Honeywell CT87N and can only get hot air. We installed the wires the exact way we pulled out of old one and now nothing works...??… read more
Airheatman
Airheatman
Heating & Air Conditioning Contractor
6 years college
1,836 satisfied customers
I am replacing a SimpleComfort 2210 thermostat with a Honeywell
I am replacing a SimpleComfort 2210 thermostat with a Honeywell RTHL3550, specifically with heat pump. The available terminals on the Honeywell are (right to left) L AUX/E G O/B NOTUSED Y R RC. The te… read more
Airheatman
Airheatman
Heating & Air Conditioning Contractor
6 years college
1,836 satisfied customers
I am swtiching from a honeywell programmable to a honeywell
I am swtiching from a honeywell programmable to a honeywell non programmable rthl3550. I have a: g, c, r, w2, o, e, y. on the old thermostat only the y and w2 were connected by metal jumper.i hace cap… read more
gotoman for ac
gotoman for ac
HVAC Technician
Associate Degree
5,357 satisfied customers
I am replacing my old thermostat with a new Honeywell 7500.
I am replacing my old thermostat with a new Honeywell 7500. The old thermostat has 6 wires: White connected to W, orange to O/W2, blue to C, red to R, Green to G, and Yellow to Y. The system is heat p… read more
Tim H
Tim H
Lead building engineer
Vocational, Technical or Trade Scho
1,922 satisfied customers
I had to replace a thermostat(white rodgers model 1f79heat
I had to replace a thermostat(white rodgers model 1f79heat pump non program) with a honeywell rthl3550 on a rheem model rpkb-030jax heat pump ac. I can get the cooling to work if i set the new therm t… read more
Richard
Richard
District Technical Manager
Vocational, Technical or Trade Scho
1,416 satisfied customers
I just bought a new thermostat, Honeywell RTH6350/RTH6450 and
I just bought a new thermostat, Honeywell RTH6350/RTH6450 and the old thermostat (Carrier) has W O G R C Y connections. this does not match the honeywell model. Which of the old wires go to the connec… read more
gotoman for ac
gotoman for ac
HVAC Technician
Associate Degree
5,357 satisfied customers
I have a HEIL HP and am replacing a Honeywell thermostat with
I have a HEIL HP and am replacing a Honeywell thermostat with a Hunter 44132. I have a Red, Green, Yellow and White wires. I have connected red to r, green to g, yellow to y. I've tried the white wire… read more
gotoman for ac
gotoman for ac
HVAC Technician
Associate Degree
5,357 satisfied customers
Hello! I am replacing an older Honeywell Non-programmable thermostat
Hello! I am replacing an older Honeywell Non-programmable thermostat with the RTH6350D Honeywell programmable thermostat. The uint is a heat/ac heatpump with emergency electric heat trip. I cannot mat… read more
HVAC_Doug
HVAC_Doug
Vocational, Technical or Trade Scho
Hello Presently I have a heat pump furnace and Im trying
Hello XXXXX have a heat pump furnace and I'm trying to change a "Water Furnace" thermostat with a Honeywell RTH8500. Presently the Water Furnace has this configuration R Y/Y2 G C W/W1 O/W2 Y1 L The Ho… read more
Rick Mather
Rick Mather
HVAC Technician
Vocational, Technical or Trade Scho
3,133 satisfied customers
I replaced my old termostat on my armstorng unit and when i
I replaced my old termostat on my armstorng unit and when i switch to a/c starts blowing hot air... the heater works fine(electric)… read more
gotoman for ac
gotoman for ac
HVAC Technician
Associate Degree
5,357 satisfied customers
I am replacing a Honeywell Chronotherm III with a VisionPro
I am replacing a Honeywell Chronotherm III with a VisionPro TH8000. THe wiring to the old thermostat has White, Green, Red, Blue and Yellow wires. Where do I map them to on the TH8000? Thanks… read more
Billy
Billy
Journeyman Service Technician
State Licensed Mechanical Contractor
9,330 satisfied customers
I have a Totaline P474-0100 thermostat and Im trying to replace
I have a Totaline P474-0100 thermostat and I'm trying to replace it with a Honeywell RTH8500 unit. The instructions state that if I have both a W1 & W2 wire connected, that I should call a licensed co… read more
Billy
Billy
Journeyman Service Technician
State Licensed Mechanical Contractor
9,330 satisfied customers
I am replacing an original Honeywell thermostat on a heat pump.
I am replacing an original Honeywell thermostat on a heat pump. The old thermostat had 6 wires they were G,C,R,Y,W2,O. I am trying to replace with a honeywell rth6300B but everytime the pump turns on … read more
Kenton Guidry
Kenton Guidry
HVAC Technician
Vocational, Technical or Trade Scho
963 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