Gas and Oil Home Heating Furnaces - Heat Pumps

North Alabama
Temp outside last week 5F
Now 24F@3AM
House 2445 ft square heated & cooled
Marvair 48HP 42.5 amps split system with 7.5 kw strips in attic. Honeywell heat pump system thermostat.
Unit was new in 1978 but we have replace compressors every 6 years since new. Just outside 5 yr guarantee periods again. In 1996 replaced compressor, reversing valve, dryer, motor contacts, both inside and outside fans, and thermostat. Tried to have relays replaced but could not get new circuit board with the three relays as Marvair is out of business.

Problem is not enough heat at the duct. Duct temp with heat pump only 73F with strips on 80F. Baseline conditions when all is perfect is 115.6-119.2 with strips on. Baseline without strips 101F.

Circuit breakers 220v both are okay, fuses in control box at strips all test okay. Large freon pipe is hot to touch at outside unit. Freon psig was 118 & 155.

When on, heat pump only, unit runs 100% of time and never reaches normal temperatures. With strips on same thing. We are only asking for 72F on thermostat. The coils outside had some frost, but no ice, like I saw years ago, prior to a fix. It appears to go to defrost mode way too often even though it shouldn't. Almost everytime it comes on it blows cold air down to 60F=maybe the cold air coming from ducts in cold attic and not defrost cycle.

We have turned back the thermostat to stay off 100% of time and bought (2) quartz 1500 space heaters. We have closed off 1/2 the house, and are living in the kitchen, family room, and two bedrooms and two baths. It is staying at 66-68F in the used living area. this AM. The closed off house is 54F. These Marvin Quartz heaters are really nice! I am think of installing another one on the ceiling in bedroom and running a 12 gauge 20 amp circuit breaker for it use only.

As an Engineer I am very unhappy with the reliability of these heat pumps and they require much money in annual maintenance. In 1996 we spent $1300 repairs hoping we would have reliabilty. Now, we are living like we did in the 50's.

Do I have a major problem, again, like compressor, reversing valve etc? I looked at the coil, in attic, and it is like new externally. I have a spare motor, for attic, and outside unit, stored for use.

The outside fan motor at times does not run even though I hear the compressor running. I was about ready to change that moor and the darn thing started running. I have a clamp on amp meters and volt ohm meters and freon gauges.

I believe my relays are bad and they are Honeywell types mounted on a small square circuit board. I have not been able to remove them, for replacement, or to get their model numbers. Every change of seasons, I have to turn off the power, discharge the capacitors, and work the relays manually, as they appear to be stuck in the wrong season setting. I work them by hand, springs at top, and spray with electronic cleaner. Sometimes I can hit the aluminum cabinet, at the electrical panel corner, with a hammer, and the heat pump will then start cooling for the sumnmer or heating for the winter. This saves removing tow sheet metal covers. This year nothing is a fix!!

I have been willing, to put up, with this, as it is a real challenge.
As, I am now retired, I have devoted, my life, to make this thing survive for a few more years. Nevertheless, I am about ready, as soon as weather permits, to design a "SYSTEM" which will be rather simple and involve very little mechanical and eletcrical equipment. I have read about geothermal systems, but they still have the compressors. My new system, will involve a hot and cold cistern, with two pumps. One pump will pump water from the cold cistern to the roof with black solar type glass covered panels to absorb the suns heat. These will drain downward by gravity as they absorb the sun's energy into my hot cistern. The hot cistern and a discharge pump will circulate hot water to a coil in the duct=maybe use the freon condenser, already there. Then flow back to either the hot or cold cistern depending on its temperature. Water to keep the cisterns full, will be provided by rain(we get 47 inches /year here) and a gutter system.

Pumps are very reliable and new types of centrifugal pumps do not have seals as the output is out the center.

What does everybody think?? Can I repair my antique Marvair, once again, at a cheap relative cost or should I begin my design of my super efficient 50 seer sun-water-air system?? I have not yet checked on the number of hot sunny days in Decatur, nor have I sized the cisterns. A geothermal requires 1000 ft of pipe per ton and on a 1/4 acre I may not have the space for such a system. I really want a perfect system that I don't have to marry the repair man or pay his country club membership and Mercedes payments!!!

Thanks for all replies..

Marvair is still in business- www.marvair.com They've graduated to making units for schools, communication shelters, etc. [pun intended] I might add that there have been several fires on their newer units. The original compressor had a 5 year warranty, but the subsequent replacement compressors only had a 1 year warranty unless you had some kind of extended warranty coverage which costs extra. I'm amazed at the amount of money you have poured into repairing an old unit. [I'm also amazed at your patience] For what you have spent over the years, you could have installed a newer, more efficient, more reliable, air source system. The refrigerant pressures you have indicated, 118/155, can I assume these are low side/high side in that order? If so, you have a broken compressor. As for the relays and the circuit board; is it the defrost board? There are plenty of generic boards available. A work around your obsolete board shouldn't be that hard using a generic time/temp defrost board and some relays. Even a system as old as yours was designed for automatic operation. No need to progressively use a bigger hammer. Take a look at www.icmcontrols.com At the home page, click on defrost controls and browse away. The defrost board should do several things:


1. reverse the cycle to cooling to defrost the outdoor coil
2. shut off the outdoor fan
3. Turn on the indoor heat strips so that warm air continues to circulate during the defrost cycle.
4. Terminate the defrost cycle when the outdoor coil is defrosted

Geothermal heat pump? Frankly, there's no reason to re-invent the wheel. They're usually done with ground loops or ground wells. Take a look at www.climatemaster.com and www.waterfurnace.com Todays units use scroll compressors which are much more realiable than reciprocating compressors. [we're talking quantum leap] Any chance you can post the wiring diagrams from both your indoor & outdoor sections on the Net? Also, what is the model # of the HW thermostat? The least the repair guy should do is let you have the Mercedes maybe 1 weekend a month.

Update:

Just to satisfy my curiosity, I called Marvair today and talked to their tech support guy. He's a long term employee and knew exactly what I was asking about. The old HW board is R8233 something [several models were made] and has been obsolete for a long time. The 3 relays on the board are changeover valve, outdoor fan and supplemental heat. they didn't have a repalcement suggestion. I tried Honeywell's website, but it looks like literature is no longer available. So, I looked at some of the boards that ICM makes, and I see no reason why you can replace the HW board with something like an ICM 300 or 3011 board. You would have to install a relay or two to replicate the functions of the relays on the HW board. The output of the board operates the relay or relays. For example, you would use NC contacts for the outdoor fan motor and NO contacts for the heat strip parallel control circuit. Whether to use NC or NO contacts for the reversing valve would depend on if it energizes for cooling or energizes for heating. While it wouldn't be a walk in the park, we wouldn't have to bring Albert Enstein back from the dead.

Im with bigjohn at 118 & 155 psi Id say your compressor has lost a valve in it. With that many compressors and motors , how good is your electric power ,is it on and off a lot and low volatage also??
Could be you need a drop out relay and time delay on this unit. Are you EPA to go in to the freon?
As far as solar for the hot water dont think it would work out .Have tried a lot of solar and it didnt do what you think.Have solar on my pool and you can feel it when a cloud goes over. So its like how many sunny days do you have in winter. Then there is a solar assisted heat pump where you use the freon in the collectors to help out this would work in the day for you.;) ED

Thanks for information.

Compressor is showing same pressure on inlet and outlet now. Outside fan is still not running. Compressor appears to be running when you put your hand on it. Have unit shutdown except for emergency heat and my quartz 1500 watt space heaters. Warming up outside to only 32.2F tonight at 10PM going up to 50F next several days with lots of rain. Talked to Bryant and American Std. service folks and have quote for a completey new unit. Bryant has copper colis wheras American Std has aluminum. I like copper. The Bryant has a scroll compressor and seer of 14.5 with the Puron freon. American Std and GE has the same alum. coils. Bryant also has a 10 year parts and labor guarantee. Can I be wrong to now go first class(Bryant???) and take my antique to the junk yard where it belongs? If I need a compressor, freon, relays and circuit board that is more than I should stand for.

Tuesday, I am going to talk to two more dealers and see what they say. I saw elsewhere, on this site, that Puron may have problems and its 100% use date of 2010 maybe delayed. Am I about to make a bad mistake?

What unit would you buy for my application taking in account the 8.2% increase in electricity rates by TVA soon to about 6,25cents/kw. Freedom from problems, is also important, to us, as I have had too many in the last 24 years. Any ideas or suggestions would be greatly appreciated. Thanks for previous answers.

I will keep you informed. Outside fan is still not running and I hot wired terminal 2 to 3 on the defrost timer tonight but the fan still didn't come on. I may install my spare fan tomorrow between talking to these next two dealers.

Could you rate these brands overall?? Maintenace frequecy repairs, cost for repairs, efficiency for heating, efficiency for cooling, your overall rating as best, second best, and third best!!

Lennox, Carrier/Bryant,Trane, Amana, Heil, York, Rudd, GE, etc??


I use 2000-2500 kw per month with my antique system. The house is super insulated. With the higher seer I expect that to cokme down to 1200-1500 monthly for a 40% reduction. In (10) years the new unit would pay for itself????By my calculations. In (10) years without any repairs??

Thanks alot!!

American Standard and Trane are essentially the same unit. They use the spine fin coil that was designed by GE decades ago and has stood the test of time. IMO- Trane is/has been the best air source heat pump on the market. Rheem is also a good unit but my vote goes to Trane. Rheem/Ruud are the same unit. Now, I hope you realize that you'll have to replace both the indoor and outdoor sections. You also want the ductwork evaluated to ensure that there is adequate airflow. With the compressor broken in the Marvair, there's no need to get the outdor fan running. You might as well just put on the heat strips alone.