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65 Cards in this Set
- Front
- Back
- 3rd side (hint)
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hydronic heating system means |
gas fired hot water heating system |
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boiler transfers heat from what to what |
burner to water through the primary heat exchanger |
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what transfers heat to rooms and how? |
the secondary heat exchanger transfers heat from water to room air through. fins. fins have a large surface area! so heats transfers easy |
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5 common heat exchangers |
•radiators● ●baseboard units• •unit heaters● ●radiant panels• • plenum mounted heat exchangers• |
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you can only use one circulating pump!? |
false you can also use several to circulate specific zones |
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name 2 zone systems |
Multi zone system!!!!! single zone system! |
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three methods of water flow are |
♤each zone has its own circulation pump and zone tstat ♡primary pumps works constantly. THEN each zone takes water from the "MAIN header".through a zone circ pump controlled by a TSTAT ◇ one circ pump buuuuut! each zone. has a TSTAT! that controls a zone Valve! water will then enter each rooms heat exchanger |
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boiler temps are controlled by? |
high/low limits of the temp controller |
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explain the sequence |
zone air temp reached!1 tstat de energizes the zone valve which closes 2 then opens the circuit to the circ pump/burner!3 if common circ pump it is controlled by any of the zone valves.... |
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imagine a multi zone control wiring diagram? how accurate were you? |
pg 3 |
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radiant panels are |
tubes installed in floors or walls also can be used to remove ice outdoors |
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give your fav example of radient panels |
in floor heating |
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what must every boiler or forced air heating have hint its in section 26-800 and 808 |
a disconnect sw |
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one problem with picking a transformer for a control boiler circuit |
zone valve requirements vary and transformer could get overloaded |
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what is the max va transformer you can use and what is the max va load for a 40va tranny |
max load for a 40 is 32 and the max tranny usable is 100va |
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several digital control systems that control variables are |
☆microprossesors control speed injection pumps for temps of water in zones ☆☆electrical signals to operate motors/gas valves ☆☆☆digital controls monitor outside temps predict requirements for the system |
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what will show indicator lights for the state of the system? |
microprossesors |
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digital controls are nice but what are pros and cons |
●energy efficient and diverse control strategy's! ■but complex and initially costly! |
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review and memorize continuous |
pg 6 |
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memorize and review intermittent |
RA is a what see hint??? |
reverse acting aquastat |
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what is the purpose of a RA and what dose ra mean |
a reverse acting aquastat prevent circulating cold water |
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main components of a hot water heating system are? |
{1}main burners/igniters {2}flame provers {3}zv's {4}circ pumps {5}safety control devices {6}temp controls |
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main burners can be??? |
HSI DEI or a standing pilot see hint form acronym explained |
HSI hot surface igniter DEI direct electronic ignition |
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standing pilot works by |
heating a THC same as basic furnace THC is see hint |
THC is thermocouple |
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standing pilots are used in new homes |
false it is not allowed in new boilers |
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dsi voltage |
10000 |
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because of the high voltage a dsi can suffer from |
dielectric breakdown |
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hsi is a |
resistant ignition device similar to a heating element in a toaster |
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when do hsi and dei turn off |
when flame proving device detects flame |
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dose a boiler need 100% and what assists that |
yes and 》》thermocouples 》》》flame rods 》》》》pyrostats 》》》》》cad cells |
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how faster do flame rods work |
fast lol |
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pyrostat is also known as a. and dose what? |
the also known as stack sw is a bimetal coil in a probe the probe senses heat after a built in delay provides a lockout shutdown |
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cad cell senses |
light from flame |
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cad cell works by |
raising its resistance when theres no light and lowering it when light is seen to 300-1000ohms
allowing I to flow |
I is current |
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how manu volts is a zone valve |
24v |
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review pg 12 13 |
review pg 12 13 |
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review pg 12 13 |
review please pg 12 13 |
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typical valves are |
two wire zv energized to open 2 wire zv energized to close 3 wire zv require power from tstat to open or close |
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3 wire zv require a special tstat that |
maintains position prior to failure |
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some 2 wire zv have a manual adjust why |
for when automatic control failed or maintenance is required |
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circ pumps have a W rating of |
1hp |
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circ pumps operate at speeds of |
1750 and 3450 r/min |
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circ pumps are loud and and reliable |
no they are quite and reliable and usually have head pressure for most resi builds |
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single stage pumps are oil or water lubed explain eache |
oil need semi annual lubing for seals amd bearings water lubed pumps use water to cool/lube the motor |
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someelectronic control systems predict |
water supply and varries the pump speed |
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electronic controls use the injection circuit to |
add 180°F from boiler to zv circuit at 120°F to keep temp consistent |
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some circ pumps run a bypass valve other run intermittently why |
intermittently prevents certain components from being unececaraly on |
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when replace circ pump make sure you |
match hp and speed rating |
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ASME means |
american society of mechanical engineers |
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ASME writes codes for what |
saftey and control devices such as low water cut-outs!!!! temp control devices!!!! aquastats!!!! flow sw!!! H.L.!!!! |
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LWCO means |
low water cut out |
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LWCO dose what |
keeps burner off is water falls below acceptable levels |
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example of a LWCO is a |
float sw |
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most common LWCO is a |
float sw |
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when LWCO senses low water level it cuts of fuel and the |
make up water control opens and feeds water to boiler |
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newer LWCOs have |
a 24v LED display |
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so temp control can be broken into 2 parts |
zone air temp for Tstat boiler temp for aquastat |
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anticupator prevents |
overshooting |
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what are aquastats and what types are there |
2 types immersion and surface mount they react to water temperature |
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immersion aquastats consist of |
consists of gas filled bulb connected to a switching mechanism through a capillary tube. the bulb is installed in a water tight well mounted in the housing of the boiler. to ensure effective conductive heat transfer, the bulb touches the bottom and the well is filled with heat conductive grease |
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aquastats are to be fail safe |
bulb ruptures contacts open |
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surface mounted aquastats work like immersion but |
mount on the side of a pipe or heat exchange surface they are not a sensitive and open/close to temp changing |
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surface mounts are good for |
high or low limit for ignition by temp sensing the boiler? |
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reverse action control |
prevents the start up of circ pump early |
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HL in aquastat |
opens circuit to kill burners preventing relief valve to open |
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