Use a fossil fuel kit to beat the predicted high

heating oil prices with a

heat pump added to your oil furnace

By G&S Mechanical Services Of Maryland.

    I received to following question from Don Kramer of Wichita KS.
My system is a Rheem Model #RPFB - 024JAS - serial number 4384 heat pump with gas backup (up flow furnace) single stage heat, single stage
 cooling - it also has a FOSSIL FUEL KIT #FXPF - D02

    Problem: When system is placed on emergency heat mode, the gas burner comes on and fan comes on right away. When system is satisfied, fan shuts off and gas valve closes immediately. Fan should continue to run until fan limit control is satisfied, but this does not happen.

 When system is placed in heat mode, heat pump and furnace works fine. (editors note: this system has an outdoor thermostat set at about 35 degrees F to switch to gas when it gets colder).

 When system is calling for the burner to come on, burner comes on and fan comes on when system is satisfied. Gas valve closes and fan continues to run until heat exchanger is cool enough to actuate fan limit control.

 Beats me why this happens in the emergency heat mode.

Scott's answer: Strange you should mention this.... Just yesterday I had my first experience  with a Rheem fossil fuel kit. It was installed on an oil furnace the wiring was a mess so I rewired it so it will detect whether or not the oil burner is running and if not it will run the heat pump instead. However someone added a relay that allows a fan signal (the G wire) to bring the fan on high but when the "G" wire is de-energized it reverts back to the limit control and low speed. My only guess is that there is a relay that is breaking the circuit to the fan. Unless by chance the furnace never gets hot enough to trip the limit control into the "ON" position, i.e. it starts the fan right away and the heat exchanger never gets hot enough.

    The situation you describe seems almost reverse of what it should be. In normal mode the thermostat engages the "G" terminal bringing on the fan and I think in  emergency mode only W2 in energized but a check with a meter will prove either way. But either way when the system is not calling for fan or the thermostat is in the off position it should revert to the limit control.

     I believe the purpose of the fossil fuel kit it to provide summer winter switch over. The "Y" terminal is used to either run the compressor (heating or cooling) or turn on the gas valve or oil burner when it is cold outside. In summer the "O" terminal is energized to make the heat pump switch to cooling. In order to prevent the burner from coming on a relay is used to disable the burner.

    Some systems are setup without an outdoor thermostat and use the "W2" terminal on the thermostat to turn off the heat pump and switch to gas or oil. That same relay can be used to disable the heatpump and release the fan relay causing the system to act as normal. The problem with this setup is that if it is too cold out for the heat pump to get the job done it will run forever until the weather gets warmer or if the thermostat is switched to "emergency heat" disabling the outdoor unit and reverting to fossil fuel which at this point would be more economical.

   The winter of 2001-2002 has predictions of very high heating oil prices which could double current fuel bills especially in January through March when the coldest part of the winter hits. The price of kerosene and propane usually follows the price of oil

    By adding or changing your air conditioning system to a heat pump you will be able to avoid the crunch of high heating oil prices.

     While many major cities now have natural gas service there are many places that still have oil especially rural areas and large installations in cities until some other source of fuel is discovered oil heat will be with us for a while.

    A heat pump has the advantage over oil in that the cost of electricity is regulated and rarely changes with demand while the price of oil changes drastically with supply and demand.

    A heat pump can be added to any forced air oil, natural gas or propane furnace where there is enough room to add a refrigerant coil. If you all ready have central air conditioning on you oil furnace it is just a simple matter to change the indoor coil or add some valves. The outdoor unit will have to be changed from a straight air conditioning system to a heat pump. The cost of doing this can pay for itself in just a few years of high oil prices. Then if the price of oil comes way down just don't use the heat pump for heating.

    In addition to saving money during a crunch if you should run out of oil  or propane during a major snow storm and can not get deliveries. A heat pump can save your family and your house plumbing from freezing because it will continue to work even when it is very cold out even in snow as long as you have electricity.

    For a price to install or change your system to a heat pump contact us by email or pager.

    There are literally thousands of heat pump service and repair companies in the county; unfortunately most repair your equipment 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.

    We here at G&S mechanical believe that the customer is entitled to have their Air conditioning unit repaired 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.

    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 or heat as well if a heat pump.

To read about fan motors and blower controls follow these links

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

Thank you for visiting our site Scott Meenen N3SJH

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