Honeywell RTH230B 5-2 Day Programmable Thermostat Large - Answered Questions & Fixed issues

I followed a comment from a previous source and reversed the polarity of the batteries. I then flipped them back to the correct position and the flashing battery indicator went away and the thermostat functions correctly.

Honeywell... | Answered on Oct 03, 2019 | 6,355 views

Hello, the snowflake flashing is a (supposed to be) 5 minute delay to prevent short cycling of the compressor. This delay can sometimes get stuck thus requiring replacement. To test , remove top of thermostat to where you can identify wires and terminals. Have someone stand near the ac unit for this test, and then take a wire or paperclip and briefly touch Rc to Y. This should start the outdoor unit. R to G will start the indoor fan

Honeywell... | Answered on Jul 06, 2019 | 23 views

Contact Honeywell and see if there is some sort of reset for unit.

Honeywell... | Answered on Mar 03, 2016 | 81 views

nothing to do with filter follow thermostat set up parameters may have been locked

If you need further help, I’m available over the phone at

Honeywell... | Answered on Feb 03, 2015 | 110 views

your thermostat may be locked go to honeywell web site punch in thermostat model # and look for set up pushing two button at the same time gets you in but you will need instuctions for set up

If you need further help, I’m available over the phone at

Honeywell... | Answered on Feb 03, 2015 | 103 views

Try replacing or installing two AA batteries. or call 1-800-468-1502 for help, that number is from the manual you read.

Honeywell... | Answered on Nov 26, 2014 | 115 views

means it is running in the cooling mode a flame means heating

Honeywell... | Answered on Sep 16, 2014 | 1,006 views

You have to take the cover off and get inside and unhook a wire. You may have 3 wires unhook 1 and if that doesn't turn it off hook it back up and unhook the next. One of them will turn it off!! Then go to the hardware and get another thermos!! You won't get a shock or anything cause it's not hooked up to any power source, they are just sensor wires. I don't know much about Honeywell, I just know I don't like their thermos. Had one once and had nothing but trouble w/it !!

Honeywell... | Answered on Jul 27, 2014 | 42 views

Please go to the link and check graph "2.5 Installing the Batteries". Its really easy so it should be a piece of cake.

Honeywell... | Answered on Mar 31, 2014 | 370 views

It could be the breaker is tripped or the blower is not getting power. Check your transformer to make sure you are getting 24 volts going to the fan relay sequencer and make sure you check your capacitor that is connected to the fan as well. sounds like a minor electrical hiccup. Also check your thermostat wires and pay close attention to anything marked w1 or w2 as these are the terminals that control the heating part of your system.

Honeywell... | Answered on Dec 01, 2014 | 330 views

Thermostats have multiple issues when you start checking them against thermometers.

1) the built-in thermometer may not match the set temperature because one or both need calibration. Compare the built-in to an external thermometer and see if there is any adjustment to make them match. Record the setting on the thermostat and the temperature when it starts and stops -- there should be a 1-3 degree range which may be adjustable. The set point should be in the middle of the on-off temperature spread.
2) the thermostat has a heat anticipator setting which may be set poorly -- turning off the heat before it reaches the set point - the fan normally runs for 1-2 minutes after the heat source is off. The anticipator is used to stop heating before reaching the set point as there are still a lot of BTUs coming out during the fan run-down -- usually 1-2 minutes.

Honeywell... | Answered on Oct 16, 2019 | 39 views

Actually the 24 hour time makes it easier to correctly set the thermostat for when you want it to change setting.

Honeywell... | Answered on Oct 03, 2019 | 46 views

No battery backup in this thermostat.

Honeywell... | Answered on Sep 25, 2019 | 51 views

You need to remove the thermostat from the wall plate to change the battery. Look on the bottom of the thermostat for a locking screw. Loosen this screw with an appropriate screw driver. Then pull the bottom of the thermostat away from the wall plate and then lift up from the bottom. When you put the thermostat back on, line up the brackets at the top of the thermostat with the slots on the wall plate. Then push the thermostat against the wall plate and tighten the locking screw.

The documentation for the Honeywell RTH2300B1012/U is available on the product page: . Click on the Manuals tab. See page 4 (page 6 of the PDF) for removing the thermostat from the wall plate. See page 9 (11 of the PDF) for replacing the batteries and putting the thermostat back on the wall plate. The current link to the manual is .

I hope this helps.

Cindy Wells

Honeywell... | Answered on Sep 13, 2019 | 46 views

A manual is what you need to unlock and reprogram the schedule. Keep off the set up steps for the thermostat, only the scheduling and security steps.

Honeywell... | Answered on Sep 12, 2019 | 31 views

Not finding what you are looking for?
Honeywell RTH230B 5-2 Day Programmable Thermostat Large Logo

Popular Tags

17 questions posted

Ask a Question

Usually answered in minutes!

Top Honeywell Heating & Cooling Experts

Bill Long

Level 3 Expert

606 Answers

Paul Carew

Level 3 Expert

3477 Answers

Cindy Wells

Level 3 Expert

6046 Answers

Are you a Honeywell Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides