heating service and heat pump repair

by G&S Mechanical:

With emphasis on repair at a reasonable cost not replacement at a high cost.

We can service and repair your existing heat pump system.

    There are literally thousands of service and repair companies in the county; unfortunately most confuse the words repair and replace by telling you that you need to replace it and how much money you will save by replacing your heat pump unit whether it works or not. Some are also very good at taking several hundred dollars a year from you to make you feel good that someone has looked at the equipment and does nothing. What we try to do is instead of a yearly or twice a year maintenance, you can have us do a minor repair or upgrade which will actually save you money and or improve comfort.

    We here at G&S mechanical believe that the customer is entitled to have their unit repaired  and modified for maximum performance unless it is just not cost effective to have it done or if the unit is really damaged. Many of the larger companies including local utilities will take advantage of simple problems like burned off wires or bad contactors that can be repaired at a nominal fee.

    There is a rumor or myth that after so many years of service (like 5 or 10) a heat pump must be replaced especially if it is icing. The fact is that properly maintained a heat pump will last for many years even 30 or more especially Trane and Rheem.

    We have seen many cases where a system is leaking refrigerant 22 for many years and the leak is obvious and can be fixed easily instead of adding refrigerant constantly.

    We have seen situations were several different companies will simply keep adding refrigerant and charging the customer for it until the compressor is ruined. Contrary to popular belief an air conditioner only needs the correct amount of freon 22; adding more will make the system work harder and not cool as well. Also if you run your unit without refrigerant you will overheat the compressor then burn it out. Once this happens you will have a real mess.

    If you have a bad reversing valve or coil you will not be able to to get the unit to cool or possibly heat if it sticks.

   If your unit turns to a block of ice in the heating mode please read this.

Why heat pumps get a bad reputation

    Many of you who have heat pumps and those of you who have heard of them or considered adding one have heard all the bad things about them.

    While I prefer other means of heating especially radiant flooring I must contend that they are a good way to heat in certain situations.
 Lets address your concerns with this list of heat pump problems:

Reason 1: Gas and oil systems are usually sized larger than they need to be and as a result one gets used to having instant heat or at least having the house warm in a hurry. A properly working heat pump will heat a house slowly and maintain it with even temperature.

Reason 2: If you push the thermostat up to get the house warm in a hurry you will usually cause the electric heat to come on and raise your electric bill. This problem can be corrected by the addition of a relay and a lockout thermostat (outside). Just switching off some of the electric stages will go a long way to saving money, any one who tells you that they can't do this is criminally incompetent.

Reason 2A: In attempts to save energy by manually setting back the thermostat you will waste all your savings. This can easily be corrected by adding a switch between the W terminal on the thermostat and the W terminal on the indoor unit. You can leave the W line from the heat pump (outdoor unit) connected and maintain your defrost heat function. If you would like the indicator lamps on the thermostat to still work then a relay can be added that will light the lamp but leave the electric heat command from the thermostat disabled. You cannot disable the indicator light unless your thermostat has a separate L terminal like some models on Honeywell or White Rodgers.

Reason 3: Heat pumps are usually sized for cooling (for good dehumidification) and the heat is made up my electric resistance heat which is expensive. If heat pumps had two speed compressors and were sized for twice the cooling need then this would be less of a problem.
 If you have a two stage system sized for cooling it will have thermostatic expansion valves in both directions and run very efficient in low mode.

Reason 4: Heat pumps loose their effectiveness  (not to be confused with efficiency) the colder it gets outside forcing you to either use the electric heat or stay cold. This is why ground source or geothermal systems work well. With a thermostatic expansion valve and clean coils a heat pump can work at very cold temperatures.

Reason 5: System that are designed poorly so the duct work is too small resulting in a lot of air noise and drafts of air that is not as warm as one would be used to on a gas or oil system.
 If you have excessive air flow and a direct drive blower the motor can be set to a lower speed without any major loss in efficiency.

Reason 6: Bad media campaigns have convinced homeowners that they don't work when they actually do quite well especially against propane or oil heat. Keep in mind that each fuel source has their lobbies. When the price of oil or gas shoot up a heat pump is very attractive.

Reason 7: If you have had oil or gas forced air in the past you may think that there is something wrong with your heat pump unit because the temperature of the discharge air is not as warm. Warmer is not always better, you can restrict the air flow and make a heat pump put out hot air but you will loose efficiency. The same is true of gas and oil.

Reason 8: If the defrost circuit is not working right when the unit goes into a defrost to prevent icing you may get a blast of cold air thinking it is normal but it can be corrected. When the unit goes into defrost mode it is actually air conditioning or cooling for a brief time.

Reason 9: They can be difficult to work on if you don't understand how they work.

Reason 10: Many contractors don't understand how they work. remember if you ask them they will tell you that they are the best but they can't repair your system and they would be more than happy to sell you a new one.

    If you have propane or oil forced air or hot water consider adding a heat pump as a back up or primary system to save money or hold you out in case you run out of fuel. if you have us install your fossil fuel kit I can rig controls so if you run out of oil or propane you can be automatically switched over to heat pump operation so your house won't freeze. The kits I have seen especially Rheem Ruud don't have a provision to detect loss of fuel. A basic fossil fuel kit is just a relay to deactivate the heat pump on a call for second stage. If this relay was connected to the oil burner motor you would have "fail safe".

The under $100 a month 5 ton unit.

    I recently (May 2002)  repaired a Rheem 5 ton unit in FT. Washington Maryland (hint 1) on the Potomac River (hint 2). This unit had a ruptured indoor coil and a bad compressor due to running the system without refrigerant. After looking at the system (May 2002) I determined that this house could definitely benefit from a two stage system since 5 tons is the largest unit that you can have on a residential single phase setup.

    I looked into the Lennox Two speed, the Trane Twin Compressor and even twinning a set of Manurope Compressors (a 3 and a 2 ) for 3 stages at $400+ each plus mounting there was no way. I then looked into the Bristol Twin single used by the York Stealth and the Carrier Two stage. I bought one and installed it for a little over $2500. (2002 prices)

    This family was offered by a friend of the family (some friend) to install a new Lennox system for $4000 but single stage and including a new indoor section that was not needed. My system re-used everything plus I added Balanced Port Expansion valves inside and out and the controls for the two stage system. At last check (Dec. 2002) they reported their last electric bills to be under $100 and they are not on a "Budget Plan". Their previous bills have been $250+ in past winters with the same unit. (2002-2003 prices)

    The system is set up with the electric heat (which draw 100+ amps, 20KW) disabled unless the emergency heat function is selected (I don't even have the defrost heat connected). They report that the full 5 tons only comes on when it gets below 30 outside. Now keep in mind that this is a large house with a lot of glass over looking the water (the reason for a 5 ton system).

    If you wish to get this same incredible performance you can order it in the York Stealth available from the Air-conditioning Exchange aircondex.com. It would be nice if your local people would sell this unit but I doubt that they will want to install a two stage system even though they will claim to only carry the best.

    The York Stealth is rated at 16+ SEER. I m not sure what mine works out to be but I can Guarantee it is better than any single stage system on the market.

    The total cost for this system was $2800 (May 2002). Plus some minor un-related repairs such as replacing a burned out fuse in the Indoor unit, repairing a minor leak on a flare fitting and most recently the power management box blew up (actually blew the door off) and tripped the breaker. Once that was repaired it was back on it merry way.

    (October 2006) there are presently 3 or more 2 stage systems offered in the residential world.

1: The Bristol Twin Single offered by York and I believe Carrier. described above.
2: The Copeland Ultra Tech Scroll which has a solenoid to shift between high and low stages.
3: 2 or more compressors, been around since the beginning and will be with us forever.
4: Copeland's 2 speed recip. Don't know if this still exists but it was a wiring nightmare especially if there was a problem with the contactor(s).
5: 3 phase compressor and a variable frequency drive "God's system". I dare any one to challenge the efficiency of variable speed with modern controls.

  This image of a heat pump TEV/TXV scheme was donated by 4Z5AY. The only technical change would be the addition of an accumulator and service valves which are left out for clarity.

Common heat pump problems

which will be the same on a straight air-conditioning system:

  1. Unit won't heat without electric or other backup:

  2. Compressor not running, short of refrigerant or out of refrigerant, reversing valve is stuck in cooling mode or halfway, not power to unit, pressure controls tripped. Too many others to name. Diagnose these problems, do not replace components to find out.
  3. Unit won't heat very well:

  4. Unit is over or under charged, unit is undersized for job, metering device problems see the charging page, poor air flow (discharge will be hot and you will hear pulses from the compressor in the refrigerant lines), indoor coils dirty (head pressure will be high), outdoor coils dirty (suction pressure will be low), compressor is weak (suction pressure will be higher than normal). In a past Summer we replaced over 10 indoor coils on units that were not cooling properly (suction pressure will be low). In heat mode a dirty coil will rob efficiency and raise head pressure.
  5. Unit freezes or turns to a block of ice:

  6. See the defrost page. This is NEVER caused by a problem with the compressor!!!
  7. When defrosting you get a blast of cold air. This is caused by the electric heat not being activated. It could be a problem with the defrost relay or the indoor section. This is not a harmful malfunction, just an annoyance.
  8. If your unit has a high pressure cut out and you keep having to reset it:

  9. Overcharged, filters dirty, metering device stuck or crapped up, combination of the above. This device is a "High Pressure Cut Out" it is NOT a "Reset Button". When it trips at 410 PSI there is a real problem that needs to be corrected. Also never have it bypassed to eliminate nuisance tripping. Correct the problem. This is NEVER caused by a problem with the compressor!!!
  10. Unit will only heat (do not confuse with aux. heat)  or cool
  11. Possibly a stuck reversing valve or no signal to the reversing valve.
  12. Outside Unit will not shut off when thermostat is not calling for heating or cooling. Cut power immediately and leave it off! See the contactor page. Same if the indoor fan will not come on. Cut power (to the outside unit) and leave it off. See the motor and blower pages.

Related links:
    Defrost explanation.
    Page with images of control panel and other stuff.
    Cooling problem page (relates to heat pumps).
    Compressor diagnosis.
    Thermostat stuff.
    Wiring colors and designations.
    Ground source heat pump installation.
    What is a hard start kit?
    What is the correct amount of refrigerant or Freon?
    Definitions of terms.

Thank you for visiting our site Scott Meenen N3SJH

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Email us at: jsmeenen@toad.net

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Written By:  Scott Meenen N3SJH of:
Specializing in Mechanical, Controls and Electrical Modifications Of
Heating, heat pump, Refrigeration, Cold storage,
Ice Production and Food preservation.
Anything having to do with Heat and Energy.
Serving MD, DC, and Northern VA