Mechanical Advisory: Water Heater Replacement

This information will be posted on the 900 Marshy Cove Bulletin Board,

More information on your hot water and heating system

http://www.900marshycove.blogspot.com/

Original Equipment: A.O. Smith Model Number: GPDT 50L 100

This unit is a 50 gallon potable water heater that services both heating and tap water. The hot water from the tank is circulated to a coil in the air handling unit. A fan blows air a across the coil and is distributed through the unit’s duct system. The tank also supplies hat water to a mixing valve, also known as an anti-scalding valve. The mixing valve blends the hot tank water with colder tap water to a safe temperature. The safe hot water is piped to all hot water faucets in the residential unit.

To all owners at 900 Marshy Cove,

The research has been done for you.

Q: What do I do if my water heater starts to leak?

Q: Who is qualified to replace it?

Q: Have they done it before?

Q: What is the replacement unit model number?

Q: What about a tank-less water heater?

Q: How much will it cost?

Q: Is there a way to detect a leak as soon as it happens?

Q: What if I am away?

Click here for a printable copy of this Replacement Guide.

Water Heater Maintenance and Replacement Guide

The water heaters in 900 Marshy Cove were installed in 2007. Many of us can expect to experience operational problems in the next few years. Recently, several have required replacement of the ignitors, safety pressure relief valves, and mixing valves. Expansion tanks have routinely required replacement.

As of May 2020, no water tank has leaked. A.O. Smith, the manufacturer warrants the tank for 10 years, so we need to be on watch for water leaks. The consequences can be very costly.

Included in this guide are maintenance tips, replacement information, and operational information.

Theory of Operation

Our water heaters use natural gas which is metered separately for each unit. The water heater has two functions: heating the unit and heating hot tap water.

Heating: The tank is connected to a set of heating coils located in the laundry room. When needed, the hot water from the tank is circulated to the coils and the fan blows the heated air through the ductwork.

Tap water: Hot tap water is also sourced from the water heater. To make it safe an “anti-scolding” value mixes the hot water with cold water to bring to it a safe temperature. The mixing valve above the tank is required by code.

Expansion Tank: The small tank above the water heater is also required by code. Since water expands when it is heated, the tank provides room for the water to expand. It contains a rubber diaphragm that is designed to accommodate the expansion. If not installed properly, the diaphragm breaks and eventually causes the tank to corrode and leak.

Controls: Near the base of the tank are the temperature controls for the tank water.

Burner and Igniter: Under the tank is a gas burner. When heat is required, the ignitor makes a spark which ignites the gas. If no flame is sensed the gas will cut off for safety.

Operation: For more detailed information including photographs, go to https://900marshycove.blogspot.com/

Water Heater

§ Set water temperature higher in the heating months.

§ In summer months, set the water heater lower.

§ If you are away for a period of time, do not turn the water heater off. Set it to “Vacation” (low) to save gas and prevent freezing.

§ Some units have an electrical baseboard heater, set it to a moderate temperature to prevent pipe freezing.

§ Set the mixing valve to control the spigot water temperature. The mixing valve keeps the temperature at a safe level no matter what the tank temperature is.

Expansion Tanks

§ Expansion Tanks should be replaced every 5 years.

§ These units must be properly pressurized to prevent leakage,

§ Check the installation date and pressure written on the tank.

Qualified Plumbers

§ Mid-Shore Plumbing, Kenny Prahl ---(410)228-9003

§ Blackwater, Vernon – (410)221-0180

§ Skip Windsor, Plumber--- (443)521-5217

Replacement options: Spec sheets are available on the 900 Marshy Cove blog site. http://900marshycove.blogspot.com/p/water-heater.html

Option One is to replace the original unit with an equivalent version. Two companies offer a 50-gallon gas water heater that is a physical match in size and piping.

A.O. Smith Model: GDPX 50L ; $1800;

Installed cost, $2500 depending on other ancillary parts.

State water heaters: Model GS6 50 YRPDTL 5; $1700;

Installed cost $2300 depending on other ancillary parts

These units are identical. One is a re-label of the same unit,

Option Two is to replace the unit with a tank-less water heater. Tank-less water heaters require less space and are more energy efficient. Without a tank, the risk of a water problem seems less likely. These units cost about twice as much. ~$6000-$7000. Tank-less water heaters have been successfully installed at Willow Oak and at 900 Marshy Cove.

Qualified Plumbers for water heater installation

· Mid-Shore Plumbing, Kenny Prahl ---(410) 228-9003

· Mid shore has installed several 50-gallon tank water heaters and has worked for several owner in our building.

Blackwater, Vernon Webb – (410)221-0180

· Blackwater has installed a tank-less water heater in 900 Marshy Cove

Qualified Installer: Proper installation is imperative as this may affect other units in the building

A qualified installer must have ability equivalent to a licensed tradesman in the fields of plumbing, air supply, venting and gas supply, including a thorough understanding of the requirements of the National Fuel Gas Code as it relates to the installation of gas fired water heaters. The qualified installer must also be familiar with the design features and use of flammable vapor ignition resistant water heaters and have a thorough understanding of this Installation and Operating manual.

Other Considerations:

The installation of a Carbon Monoxide Detector is recommended in the proximity of the water heater. These are readily available at hardware stores for $20-$30