Fourth Year - Block F Hydronic Heating Systems Flashcards
What are the four main hydronic heating piping layouts that are commonly installed?
One-pipe series loop.
One-pipe monoflow/Diversion-tee.
Two-pipe direct-return (AKA first fed first return).
Two-pipe reverse-return (AKA first fed last return).
What is the purpose of an expansion tank in a hot water heating system and where should it be located?
Regulates pressure / Thermal expansion.
(Prevents pressure relief valve from going off when the boiler fires up)
Located upstream from the system pump[][][][][][][][][][][][][][][][][][][][][][][][][][]
Where is the best location for the circulator to be installed on a hydronic heating system?
On the supply piping leaving the boiler.
(It should be downstream of the expansion tank).
On the return piping leaving the boiler[][][][][][][][][]]
What is the pressure relief valve in a residential boiler usually set to?
30 psig.
Where is the pressure relief valve in a residential boiler usually located?
On the boiler.
How much volume must the relief valve be able to relieve if necessary?
100% rating of the boiler.
What would cause the pressure relief valve to start dripping?
Waterlogged expansion tank.
What is make-up water on a hydronic heating system?
Water that is introduced into the closed hydronic system.
What is another name for the pressure reducing valve that reduces the pressure before it gets into the system?
Feed water valve.
What is the pressure in a residential hydronic heating system usually set to?
Between 12 and 20 psig.
What is a flow check valve and where is it located?
Prevents the unwanted flow of water through a system when the burner is not on.
It’s located on the supply leaving the boiler[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]]
What is the difference between a flow check and a flow switch?
Flow check is for gravity circulation and flow switch is a proving switch for the pump.
Where would you install a backflow preventer in a boiler system?
In the make-up water line on the boiler.
What is the typical backflow preventer installed in a residential boiler?
Watts 9-D.
Where would the PRV be installed in relation to the boiler?
On the make-up water line.
It should be installed after the backflow preventer.
What should the PRV be set at in a typical residential application?
Between 12 and 20 psig.
What is an air scoop and where is it located?
An air/water seperator.
Attached to the expansion tank which will be located upstream of the system pump.
(This would be where the temperature is the highest and the pressure is the lowest).
What is the “R” value of a material?
Hours / Btu / Degrees F / Feet Squared.
What is the “U” value of a material?
Btu’s / Hours / Degrees F / Feet Squared.
What does the design temperature difference (DTD) refer to?
The temperature difference between the inside of the building and the outside temp.
How do you calculate flow rate required in a hydronic heating system?
GPM = Btuh / 500 x Change in Temperature.
What do the terms “fire tube” and “water tube” refer to when dealing with boilers?
Fire tube: Flue gas travelling through the tubes surrounded by water.
Water tube: Water travelling through the tubes surround by flue gas[]
What is a conventional boiler?
Products of combustion remain relatively hot and do not condense.
What is a condensing boiler?
Most of the heat is removed from the products of combustion and the products of combustion cool down enough to condense.
What boiler is more efficient?
Condensing boiler or conventional boiler.
Condensing boiler.
The removed heat is reused.
Is there any other factor to be considered when dealing with a condensing boiler?
The condensate is acidic.
Must be neutralized before entering the drainage system.
What extra component would you require if you used boiler water to heat domestic hot water?
Heat exchanger or indirect storage tank.
(You need to seperate boiler water from drinking water).
What is the difference between a gravity hot water heating system and a closed loop hydronic system containing a circulator?
Gravity hot water heating system: Larger pipe / May be open at top / No pump.
Closed loop hydronic system: Pressurized / Pump / Smaller pipe[][][][][][][][][][][][]]
Which two variables determine how a circulator is sized in a hyrdonic heating system?
Flow rate (Gallons per minute).
Total head loss (Total head in feet).
What is the minimum return water temperature for a non-condensing boiler?
140°F.
What is a low mass boiler?
Doesn’t contain much water in the heat exchanger.
What must be proven to be working on a low mass boiler before the burner will fire?
Flow.
What proves that the pump is working on a low mass boiler?
Flow switch.
Where is the flow switch on a low mass boiler located?
On the supply leaving the boiler.
What is a chiller?
A machine that removes heat from a liquid.
What type of piping connection does a chiller usually have?
Flanged connections with flexible connectors.
What is an important consideration when determining the location of a chiller?
Isolation valves.
(To allow for maintenance).
What is a cooling tower?
Removes waste heat to the atmosphere.
How would the water level be maintained in the reservoir of a cooling tower?
Float switch.
Where should the low water cut off (LWCO) be installed in a hot water boiler?
In the supply piping above the boiler.
Where should the low water cut off (LWCO) be installed in a steam boiler?
On the boiler.
(Generally about 1 to 2 inches above the highest water tubes).
How do you cut glass sight tubes?
Score the entire tube and then gently tap or slightly heat up.
Where would you install outlets from a ducted cooling system?
In the ceiling.
Where, and at what height, is the best location to install a thermostat in a room?
Five feet above ground.
Interior wall[][][][][][][][][][][]]
Not in direct sunlight[][][]
Area where good air flow is present.
When doing routine boiler maintenance, you notice that the water in the boiler system is black and smelly. What could be concluded from this? What could you could you conclude if the water was clear?
Black and smelly (brackish): Everything is okay.
Clear: A leak in the system which would be allowing more clean fresh water in.
A unit heater is installed in a shop and is intended to supply heat to the shop area. The shop has a loading dock with a bay door. In which direction should the unit discharge?
Across the bay door.
The domestic hot water in a residence is heated by running boiler water through a water to water heat exchanger. What valve is needed on the domestic side in order to ensure the water does not become too hot?
Tempering valve.
A house is fitted with a radiant panel heating system. You are to install balancing valves in the system. Where would you install them?
On the return header.
What is a wild loop? When installing a wild loop, what component is generally installed in conjunction with it?
Acts like a pressure differential valve.
A globe valve was installed in the loop to allow for throttling.
A homeowner decides to heat his domestic hot water using a solar heating system. What does the homeowner need to install in his system in order to prevent contamination of the domestic hot water?
Heat exchanger.
A boiler is installed in a residence and the domestic heating system includes low-temperature radiant floor heating. What is required on the low-temperature heating side?
Mixing valve.
A direct return heating system is being used in a building. The heat in the rooms is not controlled individually but by a central thermostat. It is noticed that one of the rooms is hotter than the others. How can this issue be rectified?
Adjust the balancing valve.
How many btu’s are in one cooling ton?
12,000 Btu’s.
What is a triple duty valve?
Balancing Valve + Check Valve + Shut Off Valve.
How is cooling pipe (refridgeration pipe) put together?
Brazed.
Where would you install the cooling coil in a cooling system in relation to the fan?
The fan must come before (upstream of) the cooling coil.
What is the required safety valve rating for a low pressure steam boiler?
15 psig.
How do you grade a steam line in a steam heating system?
Down away from the boiler to the steam trap/dirt leg (1” in 20 ft) in direction of steam flow.
Both elements on a domestic hot water tank are working normally. What would be the cause of no hot water?
Broken dip tube.
Calcified elements.
If you have a PRV in a boiler system set at 15 psig, and the system pressure is only 7 psig, what is the problem?
PRV.
How does a steam trap operate?
Senses the difference in density between water and steam.
A low pressure steam boiler has a set operating pressure 5 psig below the maximum allowed by the ASME code. The differential of the pressuretrol is 4 psig. What is the cut-in pressure?
6 psig.
(Maximum allowed by code is 15 psig).
Which location is most suitable for the installation of a cooling tower?
Outside in a ventilated area.
What type of components might be installed with all indoor fuel oil tanks?
Drain.
Liquid level guage.
Pump[][][][][][][][][][][][]
Vent whistle alarm.
What is installed on a fuel oil system to remove suspended particles and prevent clogging of nozzles?
Screen.
What would be the most likely cause if “no-heat” complaints were being recieved from the occupants of the top floor of an apartment building?
Air lock.
What is the glycol formula?
System capacity x (required glycol % - current glycol %)
___________________________
(100 - current glycol %)
Where are the inlet and outlet connections made on a steam radiator?
Top in, bottom out.
Where are the inlet and outlet connections made on a hot water radiator?
Bottom in, top out.
Where should the relief valve be piped to in a low pressure steam system?
To a safe place.
What is them minimum size blow down drain in a low pressure steam system?
3/4”.
Heat exchanger is made from cast iron is the definition of?
Cast iron boiler.
Area where combustion occurs is the definition of?
Combustion chamber.
Water droplets which form from flue gases that have temperatures less than its dew point (typically 130 Degrees F) is the definition of?
Condensate.
Heat exchanger is made from copper is the definition of?
Copper tube boiler.
A storage vessel which recieves heat from an external heat source is the definition of?
Indirect-fired.
Boiler whos heat exchanger contains 15 usg or less is the definition of?
Low mass boiler.
Small added resistance to the thermostat designed to “trick” the thermostat into responding quicker to ambient temperatures is the definition of?
Heat anticipator.
Type of heat transfer typically through solids is the definition of?
Conduction.
Heat required to change to state of a substance from solid to liquid or liquid to gas. Also reffered to as “hidden heat” is the definition of?
Latent heat.
What temperature range do most hydronic heating systems operate?
32 - 250°F.
What is the temperature design drop with a typical hydronic system?
20°F.
(Infloor is 10°F.)
List five heat sources used for hydronic systems?
Boiler.
Electrical resistance.
Geothermal[][][][][][][][]]
Heat Pump[][][][][][][][]]
Solar[][][][][][][][][][][][][][]
Is a fire tube boiler typically high or low mass?
Typically high mass.
What do we need to be aware of with low mass boilers and how can we protect against that issue?
Need to have a flow switch located downstream of the primary circulator.
(This ensures that the water is flowing through the heat exchanger of the boiler prior to burner starting).
What temperature ranges do condensing/conventional boilers operate in?
Condensing boiler: Less than 190 Degrees F.
Conventional boiler: Greater than 190 Degrees F.
Name three methods of eliminating air from a hydronic system?
Automatic/manual air vents.
Chemical additives[][][][][][][][]
Micro bubblers[][][][][][][][][][][]
Describe how you would help meet the demands of different areas with different heating demands within the project?
Zoning.
The location of the expansion tank attachment to the hydronic system. The pressure at this point does not change regardless of whether the system circulator is on or off is the definition of?
Point of no pressure change.