InspectAPedia®   -   Search InspectApedia

Heat Pump principles Carson Dunlop AssociatesHeat Pump Repair FAQss

Q&A on Heat Pump Types, Inspection, Diagnosis, Inspection, Repairs

Heat pump system questions & answers help diagnose and fix heat pump operating problems or other heat pump questions.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

Heat Pump System Questions & Answers

What are the basic heat pump stepsto turn power back on after I turned it off?

My heat pump was making the room hotter; it had gotten up to 71 and going higher (I had the thermostat set at 64, manual mode).

To stop the persistent blowing heat I threw the breakers controlling the heat pump, depriving it of power.

I haven't had any heat for days and it's cold in here. I want to try re-starting the heat pump but want to know how to avoid damaging the system. (I'm thinking the system may "re-boot" if I put the power back on; is this possible?).

Please advise how to safely re-start the power to the heat pump system. 2019/12/16 Dorothy asked:

Moderator reply:

Dorothy

HOW to GET HEAT if the HEAT PUMP IS NOT WORKING

If your thermostat has a setting for "EMERGENCY HEAT" switch that ON; that will turn on your backup heating system.

To be clear, "emergency heat" should normally be turned on ONLY if the heat pump itself fails or won't run.

HOW TO TURN the HEAT PUMP BACK ON IN COLD WEATHER - AFTER a POWER LOSS or POWER WAS TURNED OFF

EXPLANATION of why we don’t just turn the heat pump back on and call for heat:

Watch out: When your heat pump has been OFF for several hours or longer in cold weather, you do NOT want to simply turn everything back on so as to ask the outdoor compressor unit to run. That’s because when the compressor has been off in cold weather if you suddenly turn it back on and ask it to run, liquid refrigerant may enter the compressor motor, damaging or ruining it.

That’s called “liquid slugging” at the compressor. Normally when the heat pump has electrical power a small electric heater right on the compressor motor keeps it warm in cold weather so that any refrigerant entering the compressor is in gas form, not liquid form. That prevents liquid slugging damage.

DO THE FOLLOWING:

When power to your home is on (if it was off, say due to a power failure)

1. Set the thermostat to EMERGENCY HEAT. That will give you heat while we’re waiting for the heat pump’s own internal heater to warm it up to avoid damage to the compressor motor.

2. WAIT at least six hours. (The specific amount of time you really need to wait depends on the heat pump brand and model and the outdoor temperature; you may see specific advice in your heat pump operating manual or you can call the manufacturer’s consumer help line to ask that guidance).

If you have no other information, wait at least six hours after having restored electric power to the home and to the heat pump circuit.

3. SWITCH the thermostat back to normal HEAT mode and your heat pump system should be ready to operate.

4. LISTEN: if you hear an ongoing horrible rattling banging or screaming noise coming from the outdoor compressor-condenser unit turn the system back off and call your HVAC company for repair.


MORE INFORMATION on How to use your heat pump and our list of heat pump diagnostic procedures begins at

HEAT PUMPS inspectapedia.com/aircond/Heat_Pump_Repairs.php


About the problem you had that started all of this: HEAT PUMP WOULD NOT TURN OFF:

It sounds as if there might be a short between thermostat wires (or a bad heater control board or relay)

Details on how to debug that problem are at THERMOSTAT WON'T TURN OFF inspectapedia.com/heat/Thermostat_Stuck_On.php


What would cause the system to pump itself into a vacuum in a/c mode but works in heat mode?

What would cause the system to pump itself into a vacuum in a/c mode but works in heat mode? On 2016-04-01 by Garrett -

Reply by (mod) -

A reversing valve stuck closed can cause abnormally low side suction pressures (vacuum)

 

Why is our heat pump system indoor fan running constantly?

I have a Lennox heat pump with 2 heating, 1 cooling about 2 years old. I live in Texas, and we have only had a couple days of 32 or below.

Our heater and fan run constantly. I am in a fairly solid brick home. Is there a reason for this? - On 2016-01-01 by Dirk Zollinger

Reply by (mod) -

Dirk:

Check the FAN ON setting at your thermostat and check for another FAN ON switch on the limit switch in your heater blower unit (if there is one);

If that doesn't fix the trouble search InspectApedia.com for FAN WON'T STOP to see how to diagnose and fix the trouble.

 

Question: will adding a hard-start kit on a heat pump increase the heat output in winter?

If a hard start kit is installed on a 3 yr old goodman heat pump, 2.5 ton, will it give any extra heat in the winter months ahead? (Oct 21, 2011) richie

Reply:

Richie, the hard start kit was installed to help the compressor on start up and will not increase or decrease your tonage nor the heat output of the system. - (June 26, 2012) Chad the AC Guy

Thanks Chad - Editor.

Question: low side pressure drops in a 410a Heat Pump

410a heat pump has a good charge but while the system is running the low side pressure starts dropping until the system freezes up. could this be a bad expantion valve. pressure went from 150psi to under 100psi in less than 10 minutes. head pressure almost 400 - (July 4, 2012) mike

Heil heat pump blew a transformer in the air handler - why? (Nov 10, 2012) robert

Reply: water in the system freezes the TEV / TXV; heat pump freeze-ups

To Mike -it sounds to me as if you have moisture in system; it freezes internally in the thermostatic expansion valve - TXV Valve - and ice restrictsrefrigerant flow or can keep the valve from opening when it should.

You will need to recover refrigerant, replace filter dryer, pull deep vacuum till reach 500 micron level and recharge system with virgin refrigerant.

Robert:

Perhaps your heat pump is failing to enter its defrost cycle, or the compressor heater in the outdoor unit is not working.

 

Question: outside heat pump unit won't turn on

inside air handler is running, outside unit will not come on
have low voltage to outside unit, new contactor, new themostat
Goodman units heap pump (Aug 9, 2012) Dave

Reply:

We can't diagnose this one from just your note, Dave. Your service tech will start by checking for power, then check relays and controls. Let's hope it's not the compressor itself.

 

Question: high pitched running water sound in pipes on call for heat

I have 50 year old 24 unit building with force hot water heating. I have one unit that has a high pitched sound running through the pipes when the unit calls for heat. The zone valve is fine. I have tried reducing the water going into the pipes by partially closing the valve so not as much pressure is going into that unit. It is the farthest from the boiler.

The boiler guys says it might be pressure going through the elbows of the pipes but after reading up on this could it be lime/deposit build up? When I drained some of the water it was very dirty (I drained it because I thought it might have air in the lines, but it didn't). (Jan 16, 2013) PAD said:

Reply:

Pad please see HEATING SYSTEM NOISE DIAGNOSIS

 

Question: American Standard Heritage 14 seer Heat Pump. my error code is flashing 2.

I have an American Standard Heritage 14 seer Heat Pump. my error code is flashing 2. I recently replaced the defrost control board because it would not activate the fan to kick into high rpm mode. fan seems to run constantly in outside unit and thermostat cycles between heat and auxiliary heat mode. the nights are 15-25 degrees and the days between 40-50. does my unit seem to be operating normal or should I call for service (Feb 5, 2013) Mikesanders421 said:

Reply:

2-flashes typically indicates a fault with the defrost system. I'd shut the system off and call for service; if we run the compressor in this condition it may be damaged.

 

Question: intermittent failures in air handler, then too much heat

We have something very strange going on with our heat and air unit for almost a year now. It seems to happen during the more extreme heat or cold. The unit will work intermittently. Yesterday I had lukewarm air during the day, heating the house to 65. Suddenly last night it started working, heating the house to 70.

As I was sitting here this morning I can feel times where it is blowing cold air(very cold air!) I have tried to find a pattern but there doesn't seem to be one.

Sometimes it blows cold air when it switches to auxiliary heat, sometimes not. We were renting the house this summer but the renter basically described the same thing for the cooling system. We have had our HVAC guy out on several occasions and he has replaced various things but we continue to have problems. Any advice? 21 Feb 2015 cindy said:

Reply:

Some things to check

Loose or shorted thermostat wires

Failing control board

Bad thermostat

 

Question: funny smell and heat is on, outside heat pump unit not running

Came home funny smell in house. heat still on but fan on outside not running.warm heat coming up from where fan is 24Feb 23015 Anonymous said:

Reply:

Anon

Perhaps the smell is from your backup heat turning on. Check that odor source.

 

Thank you to our readers for their generous comments

On 2021-03-02 - by Kopernikas Green

re-posting without dis-allowed advertising link

Kopernikas Green ·

Nice article. You said very well. I read this article and find some important point that is very helpful for me. Thank you very much for sharing

On 2021-02-01 by Green Leaf Air

I’m truly enjoying the design and layout of your blog.

It’s a very easy on the eyes which makes it much more pleasant for me to come here and visit more often.

Did you hire out a developer to create your theme?

Excellent work!

Reply by (mod) -

Green,

Thank you so much for the generous remark. We have been developing and tuning InspectApedia.com for over two decades now; on occasion I've tried hiring "experts" but have been disappointed that sometimes people who offer design services have a lot of opinion but no actual training, no data and less expertise than we'd have expected.

A background in publishing and computer hardware and software design for users helps as does the plethora of user comments.

So we much welcome also any questions, criticism, or suggestions you may have. Working together with actual data makes us smarter than reliance on "alternative facts".

...


ADVERTISEMENT


...

Continue reading at HEAT PUMPS - home - or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

Suggested citation for this web page

HEAT PUMP REPAIR FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.

Comment Form is loading comments...

 

IF above you see "Comment Form is loading comments..." then COMMENT BOX - countable.ca / bawkbox.com IS NOT WORKING.

In any case you are welcome to send an email directly to us at InspectApedia.com at editor@inspectApedia.com

We'll reply to you directly. Please help us help you by noting, in your email, the URL of the InspectApedia page where you wanted to comment.

Citations & References

In addition to any citations in the article above, a full list is available on request.


ADVERTISEMENT