To the Installer
Please attach these instructions next to the indirect water heater.
WARNING: Improper installation, adjustment, alteration, service or maintenance can cause serious injury or property damage. Refer to this manual. For assistance or additional information, consult a qualified installer or service agency.
CAUTION: The recommended temperature for normal residential use is 120°F. The dial on the aquastat does not always reflect the out-coming water temperature, which could occasionally exceed 120°F. The variation in out-coming temperature could be based on factors including but not limited to usage patterns and type of installation. Test your water at the tap nearest to the indirect water heater.
WARNING: Hotter water increases the risk of scald injury. Before adjusting the water temperature setting, read this instruction manual. Temperatures at which injury occurs vary with the person's age and the length of exposure.
The slower reaction time of children, elderly, and physically or mentally challenged persons increases the scalding hazard to them. It is recommended that lower water temperatures be used where these exposure hazards exist. Such households may require a temperature setting less than 120°F to prevent accidental contact with hot water.
To lower water temperature use point-of-use temperature limiting devices.
WARNING: Water heater blankets are not recommended and will void the warranty.
This manual has been prepared to acquaint you with the installation, operation, and maintenance of your indirect water heater and to provide important safety information.
To the Consumer
Please read these and all component instructions and keep for future reference.
Indirect Water Heater Instruction Manual
Warranty and Parts List are included.
Installer Responsibilities
Please read all instructions thoroughly before installing or placing the indirect water heater into service. This unit must be installed by licensed or authorized installers, or technical personnel that service water heating equipment. The indirect water heater must be installed in accordance with all local codes and ordinances.
These instructions are a guide for the correct installation of the indirect water heater. The manufacturer will not be liable for damages caused by failure to comply with the installation and operating instructions outlined on the following pages.
CAUTION: The recommended water temperature setting for normal residential use is 120°F/49°C.
Handling
Before uncrating, check for shipping damage. Report any damage to your carrier. Note damage on bill of lading or delivery receipt and file a claim.
FAILURE TO FOLLOW THESE INSTRUCTIONS OR ALL APPLICABLE BUILDING CODES AND REGULATIONS VOIDS THE WARRANTY ON THIS INDIRECT WATER HEATER.
Read all instructions thoroughly before attempting installation or operation of your indirect water heater. Keep these instructions for future reference.
Local plumbing and electrical codes must be followed in the installation of this indirect water heater. In the absence of a local code use the UNIFORM PLUMBING CODE and the NFPA Code. Local codes may supersede instructions in this installation manual.
These instructions are a guide for the correct installation of the indirect water heater. The manufacturer will not be liable for damages caused by failure to comply with the installation and operating instructions outlined on the following pages.
Section I: Specifications
Figures and Dimensions
Figure 1 illustrates the port layout for models STID30, STID40, and STID50. Figure 2 illustrates the port layout for models STID80 and STID120. Key ports include Hot Outlet, Anode Rod, Cold Inlet, T&P Relief Valve, Drain Valve, and connections for Boiler Supply and Return.
| Model | A | B | C | D | E | F | G | H |
| STID30 | 22" | 35 1/4" | 27 3/4" | 19 1/2" | 11 1/4" | 6 1/2" | 4 1/2" | n/a |
| STID40 | 22" | 42 1/4" | 34 3/4" | 31 1/2" | 16 3/4" | 6 1/2" | 4 1/2" | n/a |
| STID50 | 22" | 48 1/4" | 39 3/4" | 31 1/2" | 16 3/4" | 6 1/2" | 4 1/2" | n/a |
| STID80 | 24" | 64" | 57 1/8" | 33" | 19 1/4" | 8" | 5" | 5" |
| STID120 | 28" | 65" | 57 3/4" | 33 3/4" | 16 1/4" | 8 3/4" | 5" | 6 1/2" |
Foam insulation is standard on all indirect water heater models. Working pressure is 150 PSI. Standard voltage is 120V, 60Hz, 1P. T&P valves are factory installed with nipples supplied for top connection.
WARNING: Installation should be in accordance with all national and/or local codes.
CAUTION: The recommended water temperature setting for normal residential use is 120°F. Rheem recommends a tempering valve or anti-scald valve be installed and used according to the manufacturer's directions to prevent scalding.
Section I: Specifications (cont.)
Capacity & Performance
| Model | Actual Tank Volume (gal) | Coil Volume (gal) | Capacities | Performance | ||||
| First Hour Rating (gal)* | Continuous Draw Rating (GPH)* | First Draw Rating (gal)* | Minimum Coil Output (BTU/Hr)** | Standby Loss Rating (°F/hr) | Heat Source Friction Loss (ft. w.c.) | |||
| STID30 | 30 | 1.38 | 110 | 85 | 25 | 55,000 | 1.3 | 2.0 |
| STID40 | 38 | 2.30 | 153 | 120 | 33 | 77,000 | 1.1 | 3.0 |
| STID50 | 45 | 2.30 | 160 | 120 | 40 | 77,000 | 1.0 | 3.0 |
| STID80 | 75 | 2.76 | 200 | 130 | 70 | 83,000 | 0.9 | 5.0 |
| STID120 | 110 | 2.76 | 232 | 130 | 102 | 83,000 | 1.2 | 5.0 |
NOTES: * Based on 77°F rise with 58°F potable water inlet temperature at 8 GPM heat source flow rate. Heat source temperature was 180°F. ** Minimum Coil output based on continuous boiler operation over 30 minutes. See Section III for additional considerations. All data obtained through testing in accordance with GAMA Indirect Water Heater-FIRED WATER HEATER TESTING STANDARD IWH-TS-1_MARCH 2003
Performance (cont.)
| Model | FIRST HOUR RATING (gal) @ Coil Output (Btu/hr) | ||||||
| 180°F 6 GPM* | 180°F 10 GPM* | 180°F 12 GPM* | 200°F 6 GPM* | 200°F 8 GPM* | 200°F 10 GPM* | 200°F 12 GPM* | |
| STID30 | 107 @ 53,000 | 114 @ 57,000 | 117 @ 59,000 | 129 @ 67,000 | 132 @ 69,000 | 136 @ 71,000 | 139 @ 73,000 |
| STID40 | 141 @ 69,000 | 165 @ 84,000 | 177 @ 92,000 | 171 @ 88,000 | 183 @ 96,000 | 195 @ 104,000 | 207 @ 111,000 |
| STID50 | 148 @ 69,000 | 172 @ 84,000 | 184 @ 92,000 | 178 @ 88,000 | 190 @ 96,000 | 202 @ 104,000 | 214 @ 111,000 |
| STID80 | 188 @ 76,000 | 212 @ 91,000 | 224 @ 98,000 | 221 @ 97,000 | 233 @ 104,000 | 245 @ 112,000 | 257 @ 119,000 |
| STID120 | 220 @ 76,000 | 244 @ 91,000 | 256 @ 98,000 | 253 @ 97,000 | 265 @ 104,000 | 277 @ 112,000 | 289 @ 119,000 |
NOTES: First Hour Rating = First Draw + Continuous Draw. * Coil Input (temperature, flow rate). Ratings based on 77°F rise with 58°F inlet potable water. All data obtained through testing in accordance with GAMA Indirect Water Heater -FIRED WATER HEATER TESTING STANDARD IWH-TS-1_MARCH 2003
Section II: General Information
Location
The indirect water heater should be located in a central location to the piping system, as close as practical to the boiler and in an area not subject to freezing temperatures. Leave sufficient space for servicing and maintaining the indirect water heater.
NOTICE: Long heating supply runs can lengthen recovery times.
Water Treatment/Filtration
In areas where poor water conditions are suspected (i.e. lime, iron, and other minerals), it is essential that the water be tested and appropriate action taken to prevent damage to the indirect water heater and ensure the quality of the water.
Temperature Control
Water temperature from the heat source / boiler to the indirect water heater is controlled by an immersion aquastat. This control operates the circulator, and provides limited control for domestic hot water temperature. The proper temperature setting for domestic hot water use is 120°F/49°C. If hotter water is required a tempering device or anti-scald device must be installed at the domestic hot water outlet of the indirect water heater or at the point of use.
CAUTION: Hot water in excess of 120°F can cause scalding!
Rheem recommends a tempering valve or anti-scald valve be installed and used according to the manufacturer's directions to prevent scalding. Many state and local codes now require installation of these devices. The tempering valve or anti-scald valve will ensure potable water temperatures at the desired set point with a higher degree of accuracy.
Approximate Temperature/Time Relationships to Scalding
| Temperature | Time to Cause Scald |
| 120°F | More than 5 minutes |
| 125°F | 1 1/2 to 2 minutes |
| 130°F | About 30 seconds |
| 135°F | About 10 seconds |
| 140°F | Less than 5 seconds |
| 145°F | Less than 3 seconds |
| 150°F | About 1 1/2 seconds |
| 155°F | About 1 second |
Immersion Control
Diagram shows immersion control for STID30, STID40, STID50, STID80, STID120. Temperature setting is 120°F for all models with a fixed differential of 8°F.
Section II: General Information (cont.)
Anode Rods
The anode rod is used as a sacrificial element within the storage tank to protect against corrosion. Anode rods should be inspected twice in the first year and at least yearly. Water conditions affect consumption rate. See the Maintenance section for replacement instructions.
CAUTION: Hydrogen gas is produced in a hot water system not used for a long period (2 weeks or more). Hydrogen gas is extremely flammable. To reduce risk, open a hot water faucet for several minutes before using electrical appliances connected to the system. Listen for escaping air; do not smoke or use open flames near the faucet.
Temperature and Pressure Relief Valve (T&P)
The T&P valve is factory installed. A discharge drain tube must be installed, terminating plain, 6 inches above the floor drain. The drain tube material must be approved for temperatures of 120°F or greater, and a pressure of 150 PSI or greater.
Back-Flow Preventor (Closed Loop System)
Some local codes require back-flow preventors on potable water lines. If required, install a thermal expansion tank (designed for potable water) to prevent pressure buildup that could cause the T&P valve to discharge. Follow expansion tank manufacturer's recommendations.
NOTICE: Working pressure of the indirect water heater is 150 PSI. Do not exceed 150 PSI.
Section III: Pre-Installation
Boiler and Circulator Sizing
Ratings in this manual are based on proper selection of boiler output and circulator capacity. Table 2 ratings are based on a 77°F rise with 58°F potable water inlet temperature at an 8 GPM circulator pump flow rate, with the boiler set at 180°F. Table 3 provides additional first hour ratings at various flow rates and boiler water temperatures.
To determine the appropriate circulator, follow these steps:
- Calculate the pressure drop of all straight pipe and fittings on the supply and return at the desired flow rate.
- Add the pressure drop from Step 1 to the pressure drop through the indirect water heater coil (see Table 2 for friction loss) to obtain a total pressure drop.
- Select a circulator pump that will provide adequate flow at the total pressure drop.
A pump performance curve should accompany every circulator pump. Figures 3-5 contain performance curves for Taco and Grundfos circulator pumps, recommended by Rheem.
Figure 3: Taco 00 Series Performance Curves
This graph illustrates the performance curves for Taco 00 Series circulator pumps, showing Total Head (feet) versus Flow (GPM) and Flow (m³/h).
Figure 4: GRUNDFOS UP 15-42F Performance Curve
This graph illustrates the performance curve for the GRUNDFOS UP 15-42F circulator pump, showing Head (ft) versus Flow (US GPM) for closed systems at 60 Hz.
Figure 5: GRUNDFOS UP 26-64F Performance Curve
This graph illustrates the performance curve for the GRUNDFOS UP 26-64F circulator pump, showing Head (ft) versus Flow (US GPM) for closed systems at 60 Hz.
NOTICE: Zone valves on the heat source supply to the indirect water heater are not recommended and will drastically reduce performance.
System performance can also vary based on the heating capacity of the boiler. If the minimum coil output (assume coil output = boiler output) listed in Tables 2 and 3 is not met, the output (first hour rating) of the indirect water heater will not be met at the selected flow rate. To approximate the reduction in first hour rating as a result of low boiler capacity, use the following formula:
New first hour rating = (First hour rating) * (Actual boiler output)/(Minimum coil output)
For example, the first hour rating of a STID50 at a 77°F rise with an 8 GPM heat source flow rate using a boiler having a DOE heating capacity (output) of 60,000 BTU/Hr would be: New first hour rating = (160 gal) * (60,000 BTU/Hr)/(77,000 BTU/Hr) = 125 gal
Section IV: Installation
Water Connections
Piping between the boiler and the indirect water heater should be new copper: 3/4" ID for STID30, STID40, STID50; 1" ID for STID80, STID120. Minimize elbows. Install a flow check valve on the return line.
Domestic water connections (cold inlet and hot outlet) should be new copper: 1/2" ID for STID30, STID40, STID50; 3/4" ID for STID80, STID120.
All piping must conform to local codes and ordinances. If no local codes apply, refer to ILHR 84. Insulate all piping with approved material to ensure minimum heat loss. If a re-circulation line is used, ensure it is well insulated and the circulator is temperature controlled.
Install isolation valves for servicing. Consider installing a union on the domestic outlet for easier replacement of the hot outlet / anode nipple on STID30, STID40, and STID50 models.
Figure 6: STID30, STID40, STID50 Water Connections
Diagram shows water connections for STID30, STID40, STID50 models, illustrating connections for Domestic Hot Out (3/4"), Cold Inlet (3/4"), Boiler System Supply (1" NPT), Boiler System Return (1" NPT), Circulator Pump, Indirect Water Heater, Boiler, and a Check Valve.
Figure 7: STID80, STID120 Water Connections
Diagram shows water connections for STID80, STID120 models, illustrating connections for Domestic Hot Out (1 1/2"), Cold Inlet (1"), Boiler System Supply (1" NPT), Boiler System Return (1" NPT), Circulator Pump, Indirect Water Heater, Boiler, and a Check Valve.
NOTICE: An indirect water heater may be connected to a steam boiler provided all piping to and from the boiler is below the boiler's water line. The boiler must also be protected by a low water cut-off safety device.
Figure 8: Rheem Indirect Water Heater with Low-Mass Boiler
Diagram illustrates piping for a Rheem indirect water heater connected to a low-mass boiler, showing components such as Isolation Valves, Additional Zones, Boiler, Circulator, Air Vent, Air Separator, Expansion Tank, Cold Water Inlet, Indirect Circulator, Indirect Water Heater, and connections to the Heating Zone.
Electrical Connections
Figures 9 and 10 are general wiring diagrams. For a maintaining temperature boiler, Figure 9 should match your system. For cold start boilers, Figure 10 may be similar, but wiring varies by boiler type and controls.
When connecting to a cold start boiler, the indirect water heater operates as another heating zone. When it calls for heat, its circulator starts, the system circulator stays off, and the boiler must light to reach high limit.
Wiring Notes:
- Dashed lines indicate low voltage (24 VAC).
- Use jumper wire between terminals #1 and #3 on R845 relay.
Thermostat Specifications:
Thermostats can operate at low or line voltages.
| Voltage | Amperage |
| 24 volt | N/A |
| 120 volt | 8 amp |
| 240 volt | 5 amp |
This equipment must be properly grounded to prevent a potential shock hazard and to reduce anode deterioration due to electrolysis. Refer to local electrical codes and ordinances.
Section V: Maintenance
Water Piping
On an annual basis, check all piping for leakage at joints, shut-off valves, and unions.
T&P Relief Valve
On an annual basis, check the temperature and pressure relief valve for proper operation. Attach a drain line to direct discharge to an open drain. Lift the valve lever several times. The valve should operate freely and return to its original position. If water does not flow, remove and inspect for corrosion or obstructions. Replace if necessary. Do not repair a faulty valve.
Anode Rods
Anode rods should be inspected twice in the first year and at least yearly. Check six months after installation. If the anode rod has reduced in size by two-thirds of its original diameter (3/4") or shows pitting, it is time for replacement. Follow these steps:
- Shut off water supply.
- Open any faucet to relieve tank pressure.
- Remove caps on indirect water heater top; push insulation aside.
- Use a 1 1/16" six-sided socket wrench and a breaker bar to break the anode rod seal.
- Remove rod(s) and replace with new rod(s).
- Turn water supply back on and leave faucet open until air is out of line.
- Turn faucet off and check that new rod(s) doesn't leak.
- Snap caps back into place.
Flush the Tank
The indirect water heater is glass lined. Lime, iron, and other minerals may accumulate. Drain and flush the tank thoroughly once a year to prevent buildup.
Section VI: Troubleshooting
| Problem | Cause | Solution |
| No hot water at faucet | Boiler does not operate | Refer to boiler installation instructions. Check main service switch. |
| Circulator does not operate | Check fused disconnect. Check power supply. Replace as necessary. Check aquastat setting. Turn tank aquastat to safe temperature setting. | |
| Improper aquastat setting | Check aquastat setting. | |
| Electrical problem (relay, wiring, etc.) | Check fuse and replace. Check circuit breaker and reset (if applicable). Check power supply. | |
| Scale build-up | If boiler, circulator, and tank are operating satisfactorily, coil may have scale coating. See Section VI for tank flushing procedure. | |
| Water at faucet too hot | Aquastat set too high | Lower aquastat setting to safe level. Check manufacturer's instructions. |
| Tempering valve not properly set or defective | Check manufacturer's instructions. | |
| Insufficient hot water | Aquastat set too low | Raise aquastat setting to safe level. See Section III. |
| Undersized boiler with no priority to domestic hot water | Rewire for priority. | |
| Peak use of hot water is greater than tank storage capacity | Determine peak usage, compare to tank capacity, and add additional storage (storage tank) if necessary. | |
| Boiler cycles more than 5 times per day during hottest months | Faulty tank aquastat | Replace aquastat. |
| Excessive demand | Reduce demand or consider larger tank. | |
| Faulty aquastat | Replace aquastat. | |
| Boiler high limit set too low | Increase boiler high limit setting. | |
| Scale, hard white particles from faucets, popping sound from tank | Lime, water hardness above 7 grains / 120ppm | Water treatment; softener; etc. |
| Rust staining; bad taste and odor in water | Iron/minerals in water supply | Filtration. |
| Rotten egg odor | Hydrogen Sulfide | Flush tank with chlorine solution and install aluminum anode rod(s). Properly ground heater & replace anode rod(s). Check well pump system. |
| Air from hot water fixture | Electrolysis or air introduced by water supply | Replace dip tube. |
| Reduction in recovery | Dip tube broken or compromised by high chlorine in water | Replace dip tube. |
| Inlet/Outlet fitting corrosion | Galvanic corrosion of dissimilar metals | Install dielectric unions. |
| T&P Valve dripping water | Excessive water supply pressure; closed loop system (System Plus) requires expansion tank. | Check incoming water supply pressure; closed loop system (System Plus) requires expansion tank. |
| T&P gushing water | Excessive water temp. (above 210 °F) | Adjust or replace aquastat and T&P valve. |
Section VII: Parts List
Diagram and Parts
An exploded view diagram shows the components of the indirect water heater. The following parts are listed:
| No. | Description | Applicable Models |
| 1 | Anode | All models. |
| 2 | Anode Outlet | STID 30, STID 40, STID 50 |
| 3 | T&P Relief Valve | All models. |
| 4 | Drain Valve | All models. |
| 5 | Aquastat | All models. |
Section VIII: Limited Warranty
General
This Limited Warranty is available only to the original owner and is not transferable. Rheem warrants the water heater and its component parts to be free from defects in materials and workmanship under normal use and service for the Applicable Warranty Period. Rheem will repair or replace defective units or parts at its option.
Effective Date
The Effective Date of warranty coverage is the date of installation or the manufacture date of the water heater (whichever came first), if properly documented. Otherwise, it is the date of manufacture plus 90 days.
Applicable Warranty Periods
Tank: Six (6) years for single-family dwellings, three (3) years for other installations. Component parts: One (1) year, except LIFEGUARD™ elements (three (3) years).
Warranty Exclusions
This Limited Warranty does not cover:
- Service trips for installation, use, or maintenance instruction.
- Damages, malfunctions, or failures resulting from improper installation, non-compliance with codes, or failure to operate and maintain according to instructions.
- Performance problems due to improper sizing, gas supply, venting, or electrical issues.
- Failures from improper fuel conversion (natural gas to LP or vice versa).
- Operation with anode rod removed or with unapproved parts.
- Damage from abuse, accident, fire, flood, freeze, lightning, or acts of God.
- Tank leaks caused by corrosive or contaminated atmospheres.
- Operation with an empty tank ("dry firing").
- Operation at temperatures exceeding maximum settings.
- Operation without a supply of potable water.
- Operation beyond specified pressures or firing rates.
- Use of unauthorized attachments or energy saving devices.
- Units installed outside the USA (50 states) and Canada (10 provinces).
- Units moved from original installation location.
- Units with removed rating labels.
Labor, Materials, Shipping, and Processing Costs
This Limited Warranty does not cover labor expenses for service, repairs, reinstallation, permits, or removal/disposal. It also does not cover reinstallation material costs (pipe, valves, fittings). Rheem pays transportation costs for in-warranty replacements to a convenient delivery point. You must pay any local freight charges and return costs.
Rheem does not authorize or reimburse for claims processing or similar fees charged by third parties.
How to Obtain Warranty Claim Assistance
Make claims promptly. Determine if the unit is "in-warranty" using the model number, serial number, and installation/purchase date. Visit www.rheem.com or contact the Rheem Warranty Department at (800) 621-5622. If in-warranty, refer to the Use and Care Manual or contact Rheem Technical Service at (800) 432-8373 or www.rheem.com. You may use a local plumber/contractor at your expense.
Provide complete model number, serial number, and installation/purchase date. If an exact replacement is unavailable, Rheem will provide a current or comparable model. You may be charged for features required by government regulations or industry standards.
Rheem reserves the right to inspect or require the return of failed units or parts. In-warranty failures require the unit or part to be made available to Rheem in exchange for replacement.
Warranty compensation is subject to validation by Rheem Claims Department.
To obtain warranty compensation, provide Rheem with the failed unit (with rating label and all parts intact) or the original rating label, complete model and serial numbers of the replacement unit, and date of failure. Proof of original installation/purchase date may be required.
For defective component parts, provide the part, complete model/serial numbers of the water heater it was removed from, and date of failure. Proof of installation/purchase date may also be required.
Warranty claim documentation should be mailed to: Rheem Water Heaters, Claims Department, 101 Bell Road, Montgomery, Alabama 36117.
Exclusive Warranty & Limitation of Liability
This Limited Warranty is the sole warranty provided by the manufacturer. No one is authorized to make other warranties. Implied warranties, including merchantability or fitness for a particular purpose, are limited to the Applicable Warranty Periods. Rheem's sole liability for any defect is as set forth in this warranty. Claims for incidental or consequential damages (including water leakage) are excluded. Some states do not allow limitations on implied warranties or exclusions of incidental/consequential damages, so these limitations may not apply to you. This warranty gives you specific legal rights, which may vary by state.
Complete the information below and retain this Certificate of Limited Warranty for service needs. Reasonable proof of installation or purchase date may be required. Otherwise, the warranty effective date will be the date of manufacture plus ninety (90) days.
Owner Information:
- Name of Owner/Business: ________________________________________________________
- Water Heater Installation Location Address: _________________________________________________ _____________________________________________________________________________________
- Date Water Heater was Installed:___________________________________________________________
- Name of Rheem Retailer:_________________________________________________________________
- Address of Rheem Retailer:______________________________________________________________ _____________________________________________________________________________________
- Telephone Number of Rheem Retailer:_______________________________________________________
- Complete Model Number of Water Heater:______________________________________________________
DO NOT RETURN THIS DOCUMENT TO RHEEM. KEEP IT WITH YOUR WATER HEATER OR BUSINESS RECORDS.
