Dometic MPD 93756 Water Heater User Manual

Dometic MPD 93756 Water Heater User Manual

This water heater design has been certified by the Canadian Standards Association for installation in recreation vehicles. This water heater is not for use in marine applications.

SERVICE CALLS & QUESTIONS
The location and phone numbers of qualified Service Centers.

SAFETY ALERT SYMBOLS
Safety Symbols alerting you to potential personal safety hazards. Obey all safety messages following these symbols.

WARNING
avoid possible injury or death

CAUTION
avoid possible injury and/or property damage

Installation and service must be performed by a qualified Service Technician, Service Center, OEM, or Gas Supplier.

WARNING
FIRE OR EXPLOSION

• If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury, or loss of life.
• Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

• Evacuate ALL persons from the vehicle.
• Shut off the gas supply at the gas container or source.
• DO NOT touch any electrical switch, or use any phone or radio in the vehicle.
• DO NOT start the vehicle’s engine or electric generator.
• Contact the nearest gas supplier or qualified Service Technician for repairs.
• If you cannot reach a gas supplier or qualified Service Technician, contact the nearest fire department.
• DO NOT turn on the gas supply until the gas leak(s) has been repaired.

IF YOUR MODEL NUMBER IS NOT LISTED Older
revision numbers may be 3, 4, 6, 7, 8, or 9 ( – X ) Regardless of your revision number, the current instructions are still generally applicable to your unit. If you have questions contact your dealer, a Dometic Service Center, or the Dometic Service Department.

MODEL NUMBER CLARIFICATION

TYPE| 4 GAL| 6 GAL| 10 GAL
Pilot Ignition| G4-7| G6A-7        GC6AA-8P

GC6AA-8             GH6-7

| G10-2 G10-2P| GC10A-2 GC10A-2P
Electronic Ignition| | G6A-8E       GCH6A-9E

GC6AA-9E           GH6-8E

| G10-3E GC10A-3E| GCH10A-3E GH10-3E
Pilot Relight| P IN MODEL # – SEE MODEL CLARIFICATION ABOVE|
Heat Exchange| H IN MODEL # – SEE MODEL CLARIFICATION ABOVE|
Electronic Ignition| E IN MODEL # – SEE MODEL CLARIFICATION ABOVE|
Combination Gas/Electric| C IN MODEL # – SEE MODEL CLARIFICATION ABOVE|
DIMENSIONS|

SHIPPING WT.

6 GALLON            25 lbs

10 GALLON           32 lbs

ALL MODEL| WIDTH| HEIGHT|
6 GALLON

10 GALLON

| 16˝

16˝

| 12.5˝

15.5˝

|

CRITICAL INSTALLATION WARNINGS

• Install in recreation vehicles only. RV’s are recreation vehicles designed as temporary living quarters for recreation, camping, or travel use having their own power or towed by another vehicle
• All combustion air must be supplied from outside the RV, and all products of combustion must be vented to outside the RV.
• DONOTvent water heater with venting system serving another appliance.
• DONOTvent water heater to an outside enclosed porch area.
• Protect building materials from flue gas exhaust.
• Install water heater on an exterior wall, with access door opening to outdoors.
• DO NOT modify the water heater in any way.
• DONOTalter water heater for a positive grounding system.
• DO NOT HI-POT the water heater unless the electronic ignition system(circuit board) has been disconnected.
• DO NOT use a battery charger to supply power to the water heater even when testing.

USA AND CANADA- FOLLOW ALL APPLICABLE STATE AND LOCAL CODES-IN THE ABSENCE OF LOCAL CODE REGULATIONS, REFER TO CURRENT STANDARDS OF:

• recreation Vehicles ANSI/NFPA 1192.
• National Fuel Gas Code ANSI Z223.1 and/or CAN/CGA B149 Installation Codes
• Federal Mobile Home Construction & Safety Standard, Title 24 CFR, part 3280, or when this Standard is not applicable, the Standard for Manufactured Home Installations (Manufactured Home Sites, Communities and Set-Ups), ANSI A255.1 and/or CAN/CSA-Z240 MH Series, Mobile Homes.National Electrical Code ANSI/NFPA No. 70 and/or CSA C22.1
• Park Trailers A119.5
• CSA standard Z240 RV Series, Recreational Vehicle.

GENERAL INSTALLATION

Below is the most common type of installation for the water heater. However, there are other approved methods such as baggage compartments (refer to MPD 90093) and flush mounting installations (refer to MPD 93948). Consult your Field Auditor, Account Manager, or the Dometic Service Department if you have additional questions.

1. Locate water heater on floor of the coach before erecting side walls. The water heater tank must be permanently supported at the same level as the bottom of the sidewall cutout (by the floor or a raised floor).
2. To install a water heater on carpeting, you must install the appliance on a metal or wood panel that extends at least three inches beyond the full width and depth of the appliance.
3. If the water heater is installed where leakage of connections or tank will damage the adjacent area, install a drain pan that can be drained to outside of the coach, under the water heater.
4. Connect both 1/2˝ NPT water lines – hot water outlet female (FIG 1-A) and cold water inlet female (FIG 1-B) and 3/8˝ flared LP gas lines (FIG 1-C).
   • Allow flexibility in water and gas lines so you can pull unit forward through wall one inch past skin (FIG 2.
   • Seal gas line entrance opening by sliding grommet (FIG 1-D) onto 3/8˝ tubing (FIG 1-F) before flaring tubing (FIG 1-F). Pull gas line and grommet through an opening in the housing (FIG 1-C). Connect flare fitting (FIG 1-E) and press grommet into the opening. If gas line tubing is already flared, cut grommet on one side. Place split grommet over gas line and press it into opening.
   • Always use pipe lubricant on threads when connecting hot and cold water couplings. A suitable plastic fitting is recommended.
5. Erect side walls and cut opening. See chart and FIG 2-A & B. Frame with 2×2 lumber (or equivalent).
6. Bend all flanges 90° along scored lines (FIG3).7.To prevent water leaks caulk thoroughly around the opening, including bend slots (FIG3-A). Butyl Tape (1˝x1/8˝) may be substituted for caulking material.8.Push unit against caulking, secure 4-corner brackets FIG4-A to coach with No.8 – 3/4˝ round head screws (not furnished) or equivalent. Complete the installation by inserting the same type of #8 screws in the holes provided around the flange of the water heater housing. Check all gaskets, they must adhere to the pan creating an air tight seal.9.Attach access door (FIG5).a.Snap hinge pin (FIG5-A) into clip (FIG5-B).b.Slide cover (FIG5-C) onto hinge pin.c.Slide hinge pin into cover, snapping into clip at same time (FIG5-D).NOTE: To remove hinge pin, support access cover and apply force to corner of hinge pin as shown FIG5-E.10.Disconnect unit and its individual shut-off valve from gas supply line during any pressure testing of system in excess of 1/2 PSIG(3.4 kPa, 14˝ water column [W.C.]). DO NOTset inlet pressure higher than the maximum indicated on rating plate of gas valve (13˝ W.C.).Isolate unit from gas supply line by closing its individual manual shutoff valve during any pressure testing ≤1/2 psig.

WARNING FIRE AND/OR EXPLOSION
DONOTuse matches, candles or other sources of ignition when checking for gas leaks.11.Turn on gas and check water heater and all connections for gas leaks with leak detecting solution.12.Fill water heater tank, check all connections for water leaks (FIG1-A & B). PRESSURE-TEMPERATURE RELIEF VALVE – (FIG10)

WARNING SCALDING INJURY
The valve is not serviceable, it must be replaced. Tampering with valve will result in scalding injury. Tampering with valve will void the warranty.

WARNING EXPLOSION DO NOT
place a valve, plug or reduce coupling on the outlet part of the pressure- temperature relief valve.

THIS VALVE IS A SAFETY COMPONENT AND MUST NOT BE REMOVED FOR ANY REASON OTHER THAN REPLACEMENT. This water heater is equipped with a temperature and pressure relief valve that complies with the standard for Relief Valves and Automatic Gas Shutoff Devices for Hot WaterSystems, ANSI Z21.22. If you use a discharge line, do not use a reducing coupling or other restriction smaller than the outlet of relief valve. Allow complete drainage of both valve and line.FOR REPLACEMENT PARTS:DO NOT install anything less than a combination temperature-pressure relief valve certified by a nationally recognized testing laboratory that maintains periodic inspection of the product of listed equipment or materials, as meeting requirements for Relief Valves and AutomaticGas Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22.Valve must have a maximum set pressure not to exceed 150 psi. Install valve into the opening provided and marked for this purpose on water heater. Installation must conform with local codes or in the absence of local codes, American National Standard for Recreational Vehicles, ANSIA119.2/NFPA 50IC.For an external electrical source, ground this unit in accordance with the National Electrical Code ANSI/NFPA70. Your Dometic gas water heater is now ready for operation.

HOW TO OPERATE YOUR WATER HEATER
Electronic Ignition continues to Electronic Ignition

WIRING INSTRUCTIONS
Pilot Relight continues to Pilot Relight WIRING INSTRUCTIONS. For HEAT EXCHANGE continue

1. Push 5/8˝ dia. 2 or 3 coolant system hose with SAE 053 A Type “E”clamp attached (FIG 6-E) onto heat exchange tube as far as possible (FIG 6-B).
2. Spread the hose clamp and slide toward heat exchange unit past annular groove (FIG 6-C) and release.
3. Continue to HOW TO OPERATE YOUR WATER HEATER and/or ElectronicIgnition OPERATION.

For COMBINATION GAS/ELECTRIC MODELS continue

This water heater is designed to operate with gas, electricity, or a combination of both. Provide adequate clearance at rear of unit for service of water connections and operation of manually re-setable high-temperature limit switch on combination gas/electric units.

Follow the GENERAL INSTALLATION instructions.
NOTE: All wiring must comply with applicable electrical codes.

PRODUCT DAMAGE

1. When using Romex® with a bare earth ground, take care to position ground wire so it does not contact the heating element terminals. Use electrical metallic tubing, flexible metal conduit, metal-clad cable, or nonmetallic-sheathed cable with grounding conductor. Wire must have a capacity of 1500 watts or greater. The wiring method must conform to applicable sections of article 551 of the National Electrical Code ANSI/NFPA 70.
2. Refer to Wiring Diagram. Make 120 VAC electrical connections from the junction box on back of unit.
3. Connect hot lead to (1) Black.
4. Connect common lead to (2) White.
5. Connect ground wire from electrical service to (3) green ground lead in junction box 3. Place switch in “OFF” position.
6. When a cord and plug connection to the power supply are used on water heater, power cord must be UL listed as suitable for damp locations, hard or extra-hard usage. It must be a flexible cord such as type S, SO, ST, STO, SJ, SJT, SJTO, HS or HSO cord as described in National Electrical Code, ANSI/NFPA 70. The length of external cord to water heater, measured to face of the attachment plug, shall be no less than 2 feet nor more than 6 feet. Supply cord must be a minimum of 14 AWG and the attachment plug must be rated at 15 amps.

CAUTION
ELECTRICAL DAMAGE

1. Label all wires before disconnecting when servicing controls.
2. Verify proper operation after servicing.
3. Operation using gas continues to HOW TO OPERATE YOUR WATER HEATER, electrically continue to COMBINATION Gas/Electric OPERATION.

ELECTRONIC IGNITION – WIRING INSTRUCTIONS

Install unit according to GENERAL INSTALLATION instructions.
NOTE : It is recommended unit be connected directly to a 12V DC battery or to filtered side of an AC/DC converter. Avoid connections to the unfiltered side of an AC/DC converter whenever possible. Use a minimum of 18 gauge wire, UL and CSA listed.  Install remote switch in a convenient location. Position wall plate with letters up. Before making connections turn switch OFF. The switch is off when the button is depressed towards terminal see wiring diagram

CONSUMER SAFETY WARNINGS
WARNING
EXPLOSION OR FIRE

• DO NOT store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
• Should overheating occur, or gas supply fail to shut off, turn OFF manual gas control valve to appliance, or turn gas OFF at the LP tank. On the ELECTRONIC IGNITION, MODEL turn the operating switch to OFF position and remove red wire from left hand terminal of ECO switch or turn gas OFF at the LP tank.
• Use with LP gas only.
• Shut off gas appliances and pilot lights when refueling.
• On PILOT RELIGHT MODELS, turn off the ignition module when refueling gasoline tanks or LP tanks.
• Turn gas OFF at the LP tank when vehicle is in motion. This disables all gas appliances and pilot lights. Gas appliances must never be operated while the vehicle is in motion. Unpredictable wind currents may be created which could cause flame reversal in the burner tube, which could result in fire damage. The thermal cut off fuse could also be unnecessarily activated resulting in a complete shutdown of the water heater requiring the replacement of the thermal cut off. See maintenance of electronic ignition water heaters for further explanation of the thermal cut off.
• LP tanks must be filled by a qualified gas supplier only.

HOW TO OPERATE YOUR WATER HEATER

CAUTION
FIRE
Do not smoke or have any flame near an open faucet. If water heater has not been used for more than two weeks, hydrogen gas may form in water line. Under these conditions to reduce the risk of injury, open hot water faucet for several minutes at the kitchen sink before you use any electrical appliance connected to hot water system. If hydrogen gas is present, you will probably hear sounds like air escaping through the pipe as water begins to flow.

WARNING
SCALDING INJURY
Do not tamper with pilot orifice.

CAUTION
PRODUCT FAILURE
• Do not operate without water in tank.

PILOT OPERATION

1. Turn gas control valve knob (FIG 7-B or FIG 8-B) to OFF position.
2. Wait at least five minutes to allow accumulated gas in burner compartment to escape.
3. Water heater may be equipped with a White Rodgers® orRobertshaw Unitrol® Control.

PREVENTATIVE MAINTENANCE

Spiders, mud wasps, and other insects can build nests in the burner tubes. This causes poor combustion, delayed ignition or ignition outside the combustion tube. Listen for a change in burner sounds or in flame appearance from a hard blue flame to a soft lazy flame or one that is very yellow. These are indications of an obstruction in burner tube (FIG 9-C). Inspect and clean on a regular basis.

• Remove air shutter screw (FIG 9-A) and slide air shutter (FIG 9-B) down burner tube.
• Run a flexible wire brush down burner tube (FIG 9-C) until it is visible at end of burner tube.
• Vacuum burner where it enters the combustion tube.
• Return air shutter to original position and replace screw.
• The orifice, burner tube and shutter must be aligned so that the shutter is not binding on the air tube.

HOW TO CLEAN PILOT MODELS

1. Check main burner orifice and pilot assembly for contamination (dirt, spider webs, etc.).
2. Clean main burner tube with small brush.
3. Main burner adjustment – open air shutter 1/4 way.
4. Low pilot flame. Check for contamination – if clean have the pilot orifice replaced.

HOW TO CLEAN ELECTRONIC IGNITION MODEL

1. Check main burner orifice.
2. Clean and adjust main burner.
3. The main burner and valve manifold must align with each other
4. Check the electrode for cracked porcelain.
5. Check electrode for proper gap – 1/8” between electrode and ground.
6. If module board functions intermittently, remove the board and clean the terminal block with a pencil eraser.

WATER HEATER TANK CARE

SCALDING INJURY
Turn off the water heater and allow time for water to cool before removing drain plug to flush tank.

WINTERIZING (FLUSHING) INSTRUCTIONS
To ensure the best performance of your water heater and add to the life of the tank, periodically drain and flush the water heater tank. Before long term storage or freezing weather drain and flush the tank.

1. Turn off main water supply (the pump or water supply (the pump or water hook-up source).
2. Drain the Water Heater Tank by removing the drain plug. If the water flows sporadically or trickles instead of a steady stream of water, we recommend the following action; first open the Pressure Temperature Relief Valve to allow air into the tank and secondly, take a small gauge wire or coat hanger and poke through the drain opening to eliminate any obstructions.
3. After draining the tank, because of the placement of the Drain Plug, approximately two quarts of water will remain in the tank. This water contains most of the harmful corrosive particles. To remove these harmful corrosive particles flush the tank with either air or water. Whether using air or water pressure, it may be applied through the inlet or outlet on the rear of the tank or the Pressure Temperature Relief Valve. (If using the Pressure Temperature Relief Valve the Support Flange must be removed). The pressure will force out the remaining water and the corrosive particles.

If you use water pressure, pump fresh water into the tank with the assistance of the on-board pump or use external water for 90 seconds to allow the fresh water to agitate the stagnant water on the bottom of the tank and force deposits through the drain opening. Continue repeating adding water and draining until the particles have been cleared from the water remaining in the tank. Replace the Drain Plug and close the Pressure Temperature Relieve Valve. The approximately two quarts of water remaining in the tank after draining will not cause damage to the tank should freezing occur.

PRESSURE-TEMPERATURE RELIEF VALVE

WARNING
EXPLOSION

• Do not place a valve, plug or reduce coupling on the outlet part of the pressure-temperature relief valve.
• A Pressure Temperature Relief Valve, dripping while the water heater is running, DOES NOT mean it is defective. During the normal expansion of water, as it is heated in the closed water system of a recreation vehicle, the Pressure Temperature Relief Valve will sometimes drip. The
• A domestic water heater tank is designed with an internal air gap at the top of the tank to reduce the possibility of dripping. In time, the expanding water will absorb this air and it must be restored.

WARNING
SCALDING INJURY
Turn off the water heater before opening the pressure-temperature relief valve to establish air space. Storage water must be cool.

TO REPLACE THE AIR GAP FOLLOW THESE STEPS

1. Turn off main water supply (the pump or water hook-up source).
2. Let water cool or let run until cool.
3. Open the hot water faucet closest to the water heater.
4. Pull the handle of pressure temperature relief valve straight out and allow water to flow until it stops.
5. Allow pressure temperature relief valve to snap shut; close faucet; turn on water supply.
6. Turn on water heater and test.
7. at least once a year manually operate the pressure-temperature relief valve (FIG 10).
8. When the pressure-temperature relief valve discharges again, repeat above procedure.
9. For a permanent solution, we recommend one of the following
10. install a pressure relief valve in cold water inlet line to water heater and attach a drain line from valve to outside of coach. Set to relieve at 100-125 PSI.
    • Install a diaphragm-type expansion tank in cold water inlet line.
    • Tank should be sized to allow for expansion of approximately 15 oz. of water and pre-charged to a pressure equal to water supply pressure. These devices can be obtained from a plumbing contractor or service center.

FLUSHING TO REMOVE UNPLEASANT ODOR
A rotten egg odor (hydrogen sulfide) may be produced when the electro galvanic action of the cladding material releases hydrogen from the water. if sulfur is present in the water supply the two will combine and produce an unpleasant smell.

1. Turn off the main water supply. Drain the water heater tank and reinstall drain plug. Remove the pressure-temperature relief valve. Mix a solution of 4 parts white vinegar to two parts water. With a funnel, carefully pour the solution into the tank.
2. Cycle the water heater with the above solution, letting it run under normal operation 4-5 times.
3. Remove the drain plug and thoroughly drain all water from the tank. Flush the water heater to remove any sediment. You may flush the tank with air pressure or fresh water. pressure may be applied through either the inlet or outlet valves on the rear of the tank or through the pressure-temperature relief valve coupling located on the front of the unit.

TO FLUSH THE TANK WITH AIR PRESSURE
Insert your air pressure through the pressure-temperature relief valve coupling. With the drain valve open, the air pressure will force the remaining water out of the unit. To flush tank with water pressure:

1. Fresh water should be pumped into the tank with either the onboard pump or external water pressure. Continue this flushing process for approximately 5 minutes, allowing the fresh water to agitate the stagnant water on the bottom of the tank and forcing the deposits through the drain opening.
2. Replace the drain plug and pressure-temperature relief valve.
3.  Refill tank with fresh water that contains no sulfur.
4. The Dometic water heater is designed for use in a recreation vehicle. If you use your vehicle frequently or for long periods of time, flushing the water heater several times a year will prolong the life of the storage tank.

WIRING DIAGRAMS

VEILLEUSEPART IDENTIFICATION

FOR IDENTIFICATION AND REPAIR PARTS GO TO: WWW.DOMETIC.COM CHOOSE THE WATER HEATER CATEGORY THEN THE STYLE OF WATER HEATER USE THE MODEL NUMBER LOCATED ON THE UNIT TO FIND PARTS

PART IDENTIFICATION

LIMITED TWO-YEAR WARRANTY

• LIMITED TWO-YEAR WARRANTY AVAILABLE AT WWW.DOMETIC.COM/WARRANTY.
• IF YOU HAVE QUESTIONS OR TO OBTAIN A COPY OF THE LIMITED WARRANTY FREE OF CHARGE, CONTACT:
• DOMETIC CORPORATION CUSTOMER SUPPORT CENTER 1120 NORTH MAIN STREET ELKHART, INDIANA, USA 46514 +1-800-544-4881 OPT 3

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