Electric
One of the most expensive forms of heat. Electric resistance heat has never been cheap and heat pumps are often used to help reduce consumption. If you have electric baseboard heat then you are stuck with straight electric resistance heat. If you have forced air, then you can add on a heat pump. The only things to check on electric baseboard heat are: Getting full power, Breaker on? Wires broken or burnt? Thermostat bad? Limit switch open? Heater bad? And thats about it. Low maintenance but high utility bills. Electric forced air or boilers.
1. Check the limit switches and fusible links. Replace with like kind.
2. Check the sequencer, which brings on the heater coils in stages. It is the main control for the unit.
3. Check the heater coil itself with an ohm meter. If the circuit is open the heater coil is shot.
4. Check the obvious things, fuses, thermostat, etc.
Heat Pumps
Used in conjunction with other types of heat, gas, oil but mainly electric. Many consumers installed heat pumps to get a better electric rate/discount from their electric utility company. It is worth having a heat pump if you have a high utility rate such as electric or oil. If you have gas heat then I don't know why you would use an electric heat pump. The problem with heat pumps is the air temperature is not as high as conventional forms of heat. It blows around 70-72 degree air and a lot more of it to maintain temperature. I think they are drafty by nature. Still they will help cut your utility bills especially when outside temps are above 30 degrees. Outdoor temps below 34/35 degrees, heat pumps need a secondary back up heat to kick in.
Check all the obvious things you would check in an A/C unit plus.
1. The 4 way reversing valve, it may be stuck or the coil may be bad. Changing them is no fun, especially in the snow.
2. The defrost timer. If the unit is covered in ice it may not be defrosting. also check the defrost temp limit switch. It defrosts by going into A/C mode without the condenser fan. A temp limit sensor on the outdoor coil usually tells the unit when to quit defrosting to prevent overheating.
3. The evaporator coil, refrigerant, metering device. It has to be able to reverse direction for heating or A/C.
4. The indoor blower/filter. The indoor unit becomes the condenser in heating mode and needs to move as much air as possible.
5. The transformer needs to bigger than regular a heating unit. It must operate the 4 way valve and other controls. A normal heating unit takes a 40 VA. A heat pump needs a 75 VA.
6. The thermostat also has a 2 stage configuration plus emergency heat. 1 stage being the heat pump, 2 stage being back up heat. If the heat pump can't be repaired immediately you can always go to emergency heat.
7. Make sure to take your refrigerant pressure readings from the proper service ports. The access ports on the suction and liquid line will give you the same reading. You need to get the suction reading after the 4 way valve, right on the tubing next to the compressor or a specially designated port.
8. The only thing I hate worse than heat pumps are, you guessed it, oil heat.
A/C & Refrigeration Tips.
a. If a system needs recharged you know there is leak somewhere. Try to find it, OK? I know it's late and you have more calls to do but if you don't fix the damn leak you will have to drive all the way back there again someday and possibly fix it for free. Why not just do it the first time? I'm waiting for your answer.
b. The best place for a leak is: A/C- The service valves, caps and ports.
Look for oil - Evaporator
- Solder fittings, look for the oil.
Heat-Pump- same as A/C but also check
the suction accumulator.
Refrigeration- The expansion valve
-service valves
-solder fittings.
-sometimes the sight glass/drier.
-tubing that rubs against something.
c. Don't even bother trying to fix a leak in aluminum tubing. Used widely for years because of it's price compared to copper, it is now almost obsolete. Leaks in aluminum coils= new coils or new units.
d. Don't condem a compressor until you check the start capacitor/relay and assure it's getting full voltage as required.
e. If a compressor is very hot and not running it still may be OK. A compressor relys on returning suction gas to cool it. If a unit runs low on charge it will overheat the compressor until it shuts off on internal safety overload. Shut the unit off till it cools, you should be able to keep your hand on the top of the compressor without screaming in pain. Turn it back on and if the compressor starts, check the charge. this is very, very common.
f. If a compressor has low head pressure and high back pressure, it's valves are probably going bad. Pull it into a vacuum by shutting the condenser valve. It should pull way down to -30 on your gauge set. If it doesn't, it needs replaced. Often, a freezer compressor will start going bad and act like a cooler. It just won't get below 20 degrees, soon it quits completely.
g. If you overcharge a unit, the hot gas line will actually get cool from pumping liquid. It won't be long before you blow the compressor.
h. If you have a restriction, check for cold spots in the liquid line or a cold filter drier, that will be where the restriction is. Also, a restriction will pump down the system and give you low head pressure as well as low suction pressure.
i. Don't always try to clear the sight glass when charging a unit, especially on air conditioners. Go by your pressure readings instead.
j. Check motor rotation on 3 phase units,change any 2 wires to reverse rotation.
k. Remember the indoor section/furnace is part of the system also. Go check it.
k.More tips are coming and yours are welcome on feedback.
GENERAL INFO
1. Removing a fan or blower wheel.
This is a good one. A rusty old wheel or fan on a rusty old shaft. I always sell a new shaft with any wheel or a new fan blade with any motor (if I can find one). Sometimes you have to get the old one off.(2 things, this doesn't mean I am giving my customer "the shaft" and getting the old one off, well, keep your thoughts to yourself.) So where was I?
Oh yeah, removing wheels, pulleys and blades. The trick is to use good sandcloth and sand the shaft real well. Then wipe it and oil it. Hopefully you loosened all the set screws and there may be more than one. Now hold the shaft on the flattened part with a crescent wrench so it doesn't turn, or use channel locks somewhere on the shaft that you will never have to slide anything over. Now turn the wheel or blade with channel locks or pliers and break it free. Once you get the wheel to turn you got it made. Keep turning it while working it off the shaft. If you want to tap on the shaft put a piece of wood on it. Never, ever, never ,ever start pounding on the end of the shaft. Once you flatten that end you may as well forget it. It can get real ugly and involve many curse words. Some new curse words may even come into being, who knows. So sand it, clean it, oil it and turn it. Got it? Scot. How about this tip! Valves. When you disconnect piping and there is a valve handy you need to turn it off and ALSO cap off the piping. Don't leave a pipe open with just a shut valve preventing a possible disaster. I have seen this many times, especially old pilot valves. If someone, like a child, happens to turn on the valve there may be big problems. Even if you are on a job site installing new units, don't leave open piping, not even overnight. Cap it or plug it. If you don't, you are asking for trouble. See I bet you knew that, huh?
More to Come!!!!!!!!!!!!
| Electric One of the most expensive forms of heat. Electric resistance heat has never been cheap and heat pumps are often used to help reduce consumption. If you have electric baseboard heat then you are stuck with straight electric resistance heat. If you have forced air, then you can add on a heat pump. The only things to check on electric baseboard heat are: Getting full power, Breaker on? Wires broken or burnt? Thermostat bad? Limit switch open? Heater bad? And thats about it. Low maintenance but high utility bills. Electric forced air or boilers. 1. Check the limit switches and fusible links. Replace with like kind. 2. Check the sequencer, which brings on the heater coils in stages. It is the main control for the unit. 3. Check the heater coil itself with an ohm meter. If the circuit is open the heater coil is shot. 4. Check the obvious things, fuses, thermostat, etc. |
| Heat Pumps Used in conjunction with other types of heat, gas, oil but mainly electric. Many consumers installed heat pumps to get a better electric rate/discount from their electric utility company. It is worth having a heat pump if you have a high utility rate such as electric or oil. If you have gas heat then I don't know why you would use an electric heat pump. The problem with heat pumps is the air temperature is not as high as conventional forms of heat. It blows around 70-72 degree air and a lot more of it to maintain temperature. I think they are drafty by nature. Still they will help cut your utility bills especially when outside temps are above 30 degrees. Outdoor temps below 34/35 degrees, heat pumps need a secondary back up heat to kick in. Check all the obvious things you would check in an A/C unit plus. 1. The 4 way reversing valve, it may be stuck or the coil may be bad. Changing them is no fun, especially in the snow. 2. The defrost timer. If the unit is covered in ice it may not be defrosting. also check the defrost temp limit switch. It defrosts by going into A/C mode without the condenser fan. A temp limit sensor on the outdoor coil usually tells the unit when to quit defrosting to prevent overheating. 3. The evaporator coil, refrigerant, metering device. It has to be able to reverse direction for heating or A/C. 4. The indoor blower/filter. The indoor unit becomes the condenser in heating mode and needs to move as much air as possible. 5. The transformer needs to bigger than regular a heating unit. It must operate the 4 way valve and other controls. A normal heating unit takes a 40 VA. A heat pump needs a 75 VA. 6. The thermostat also has a 2 stage configuration plus emergency heat. 1 stage being the heat pump, 2 stage being back up heat. If the heat pump can't be repaired immediately you can always go to emergency heat. 7. Make sure to take your refrigerant pressure readings from the proper service ports. The access ports on the suction and liquid line will give you the same reading. You need to get the suction reading after the 4 way valve, right on the tubing next to the compressor or a specially designated port. 8. The only thing I hate worse than heat pumps are, you guessed it, oil heat. |
| A/C & Refrigeration Tips. a. If a system needs recharged you know there is leak somewhere. Try to find it, OK? I know it's late and you have more calls to do but if you don't fix the damn leak you will have to drive all the way back there again someday and possibly fix it for free. Why not just do it the first time? I'm waiting for your answer. b. The best place for a leak is: A/C- The service valves, caps and ports. Look for oil - Evaporator - Solder fittings, look for the oil. Heat-Pump- same as A/C but also check the suction accumulator. Refrigeration- The expansion valve -service valves -solder fittings. -sometimes the sight glass/drier. -tubing that rubs against something. c. Don't even bother trying to fix a leak in aluminum tubing. Used widely for years because of it's price compared to copper, it is now almost obsolete. Leaks in aluminum coils= new coils or new units. d. Don't condem a compressor until you check the start capacitor/relay and assure it's getting full voltage as required. e. If a compressor is very hot and not running it still may be OK. A compressor relys on returning suction gas to cool it. If a unit runs low on charge it will overheat the compressor until it shuts off on internal safety overload. Shut the unit off till it cools, you should be able to keep your hand on the top of the compressor without screaming in pain. Turn it back on and if the compressor starts, check the charge. this is very, very common. f. If a compressor has low head pressure and high back pressure, it's valves are probably going bad. Pull it into a vacuum by shutting the condenser valve. It should pull way down to -30 on your gauge set. If it doesn't, it needs replaced. Often, a freezer compressor will start going bad and act like a cooler. It just won't get below 20 degrees, soon it quits completely. g. If you overcharge a unit, the hot gas line will actually get cool from pumping liquid. It won't be long before you blow the compressor. h. If you have a restriction, check for cold spots in the liquid line or a cold filter drier, that will be where the restriction is. Also, a restriction will pump down the system and give you low head pressure as well as low suction pressure. i. Don't always try to clear the sight glass when charging a unit, especially on air conditioners. Go by your pressure readings instead. j. Check motor rotation on 3 phase units,change any 2 wires to reverse rotation. k. Remember the indoor section/furnace is part of the system also. Go check it. k.More tips are coming and yours are welcome on feedback. |
| 1. Removing a fan or blower wheel. This is a good one. A rusty old wheel or fan on a rusty old shaft. I always sell a new shaft with any wheel or a new fan blade with any motor (if I can find one). Sometimes you have to get the old one off.(2 things, this doesn't mean I am giving my customer "the shaft" and getting the old one off, well, keep your thoughts to yourself.) So where was I? Oh yeah, removing wheels, pulleys and blades. The trick is to use good sandcloth and sand the shaft real well. Then wipe it and oil it. Hopefully you loosened all the set screws and there may be more than one. Now hold the shaft on the flattened part with a crescent wrench so it doesn't turn, or use channel locks somewhere on the shaft that you will never have to slide anything over. Now turn the wheel or blade with channel locks or pliers and break it free. Once you get the wheel to turn you got it made. Keep turning it while working it off the shaft. If you want to tap on the shaft put a piece of wood on it. Never, ever, never ,ever start pounding on the end of the shaft. Once you flatten that end you may as well forget it. It can get real ugly and involve many curse words. Some new curse words may even come into being, who knows. So sand it, clean it, oil it and turn it. Got it? Scot. |
| More to Come!!!!!!!!!!!! |
