Commercial Storage Gas

Operations at temperatures above 80°C

Rheem commercial gas models 621 265, 631 265, 621 275, 631 275 are designed to operate at temperatures up to 82°C for sanitising and other applications.

Where the water supplied by the water heater is required consistently at any temperature above 80°C, we strongly recommend you use a pumped recirculation system. (Please refer to the Equa-Flow® section.)

Gas pipe supply

The gas supply piping should be sized in accordance with AS/NZS 5601.1

The gas supply pipe must be sized so that the minimum gas pressure is available at the inlet to each water heater when all appliances are operating at maximum gas consumption.

The minimum gas pressures are 1.13 kPa for natural and SNG, 2.75 kPa for propane and butane and 0.75 kPa for town gas and TLP.

Approximate daily energy consumption

These daily gas consumption figures are approximate. They’re based on:

• A daily usage of hot water per water heater in litres, at 50°C rise
• Using natural gas, but they can be used with reasonable accuracy for other gas types
• Mains pressure supply systems only

The figures do not allow for pipe heat losses. An additional allowance must be made for large manifold systems and installations designed with a circulated flow and return system.

Use the table to calculate

• The approximate energy cost for a particular installation
• The average daily hot water consumption when the energy consumption is known

To convert to kg of Propane, divide MJ by 49.5. To convert to litres of Propane, divide MJ by 25.3.

Solve several problems with room sealed fluing

The Rheem model 631 275 can be installed inside a plant room as part of a room sealed installation, using the Rheem Room Sealed Balanced Flue kit, P/No 299135.

This is the ideal solution for a difficult installation, because it solves several problems.

You don’t need to worry about ventilation into the plant room, or the need for fan assistance when discharging flue products horizontally.

Nor do you need to run a flue to a satisfactory vertical discharge point (usually at the top of the building).

The Room Sealed Kit is designed to enable flue products to be discharged up to 3 metres total flue discharge length from the water heater. It can incorporate up to 3 x 90° bends.

Interconnecting nominal 150mm inlet air and flue ducting should be supplied by the installing plumber.

The kit includes transition pieces, which are designed to accept twin skin flue tubes.

The Room Sealed Balanced Flue kit can be fully installed from within the plant room.

It’s suitable for walls up to a maximum thickness of 300mm, and it reuses the balanced flue from the water heater by relocating it on the external wall of the plant room.

A minimum plant room height of 2400mm is required, and the minimum clearances required for balanced flue terminals (as stated in AS/NZS 5601.1) must be observed.

This includes a minimum of 300mm between balanced flue terminals for this model.

Power Flue and Remote control

Rheem commercial models 621 265, 631 265, 621 275, 631 275 may be controlled by a remote device such as a time clock, remote isolating switch, pressure switch or sail switch. Additionally, Rheem can assist with Power Flue design solutions for Rheem and Raypak® commercial gas water heaters. For further details please contact your local Rheem technical advisory service.