Marey Water Heater Installation Guide — Step by Step

Marey water heater installation varies significantly by product type. Point-of-use electric, whole-house electric, and gas/propane tankless each have different infrastructure requirements. Below: the install procedure for the Marey category.

Pre-installation requirements

For electric tankless (point-of-use or whole-house)

• Adequate electrical service: panel size and main breaker capacity
• Dedicated circuit at correct amperage
• Correct wire size (typically 8 AWG for residential whole-house, smaller for POU)
• Disconnect within sight of unit
• Water supply with shutoff valve

For gas/propane tankless

• Adequate gas line size (often requires upgrade to 3/4" or larger)
• Proper gas pressure regulation
• Sealed combustion venting (concentric or parallel)
• Combustion air for ventilation (per code)
• 120V electrical supply for controls
• Water supply with shutoff valve

Step 1: Mount the unit

1. Identify wall mounting location with adequate clearance per Marey spec
2. Verify wall can support the weight (some units are 30–60 lbs)
3. Drill anchor holes; install hardware
4. Hang the unit on the mounting bracket
5. Verify level and secure

Step 2: Water connections

1. Connect cold water inlet — typically 3/4" NPT
2. Connect hot water outlet
3. Install isolation valves and service ports (recommended for descaling access)
4. Install pressure relief valve and discharge tube (if not factory-installed)
5. Apply Teflon tape or paste to threaded fittings

Step 3: Electrical (electric models)

1. Verify breaker off and locked out
2. Connect L1, L2, ground at the unit's electrical junction
3. Torque terminals per Marey spec (typically 18–22 in-lb)
4. Verify wire gauge matches breaker rating
5. Install disconnect within sight of unit if not already present

Step 4: Gas/propane connections (gas models)

1. Connect gas line with appropriate fitting
2. Pressure-test all connections (soap solution; any bubbles = leak)
3. Verify supply pressure with manometer at unit inlet
4. Install vent pipe per Marey venting spec
5. Verify proper rise and termination

Step 5: Fill and bleed

1. Open cold water supply
2. Open any service ports to allow air escape
3. Open hot faucet to fully purge air
4. Close service ports
5. Verify steady water flow at hot faucet (no spitting/sputtering)

Step 6: First fire / first power-on

1. Restore power (electric) or open gas (gas)
2. Activate by running hot faucet at minimum flow above the unit's activation threshold
3. Verify display shows operation and water heats
4. Confirm temperature at fixture is at setpoint
5. Cycle on and off 2–3 times to verify normal operation

Critical installation checks

• Electrical: verify zero voltage drop at the unit terminals under full load
• Gas: verify gas pressure at the unit inlet is in published spec under demand (not just static)
• Water: verify minimum flow rate triggers activation (some units need 0.8 GPM minimum)
• Pressure: verify water supply pressure within unit spec (typically 30–80 psi)
• Venting (gas): verify no obstruction in vent or air intake

Common install mistakes

• Undersized electrical circuit (breaker trips under load)
• Undersized gas line (insufficient supply pressure under demand)
• Missing isolation valves (no descaling access)
• Wrong polarity or loose terminals (intermittent operation)
• Venting too long or with too many elbows (insufficient draft)
• Missing pressure relief valve (code violation, safety issue)

Post-install commissioning

• Set temperature setpoint to safe operating range (typically 120°F for residential)
• Register the warranty within Marey's required window
• Document install configuration for future service reference
• Plan annual descaling reminder (calendar entry)