Raypak B0147 Model Pump Branch Size Minimum Manifold Header, Pump Selection, Relief Valve Drain

CONNECTIONS - PLUMBING

The table below provides indicative pipe and pump sizes for typical installations

Model	Pump		Branch Size			Minimum Manifold Header
							Size Required (mm)
	UPS	Speed	inches	mm	1		2	3	4
	Series				Unit		Units	Units	Units
109	20-60B	3	1	25	25		32	32	40
147	20-60B	3	1	25	20		32	32	40

PUMP SELECTION

In order to obtain the best possible water flow in the system a correctly sized pump must be installed. Refer to the Flow Rate and Pressure Drop table below and allow for the system head pressure when sizing the pump.

The pump selected should provide a 10 to 20°C temperature difference between the water heater inlet and outlet when the water heater is at full fire.

Mechanical heating systems with multiple zones may require additional pump(s) refer to ‘Multi Pump Options’ on page 28.

WATER FLOW RATE AND PRESSURE DROP

	10°C Rise		15°C Rise			20°C Rise
Model	l/sec	kPa	l/sec	kPa	l/sec	kPa
109	0.5	5.0	0.4	4.0	0.3	3.0
147	0.8	5.0	0.5	3.0	0.4	3.0

PRESSURE RELIEF VALVE

The pressure relief valve and elbow are shipped in a plastic bag inside the water heater. The pressure relief valve must be fitted before the water heater is operated.

Fit the elbow supplied in the plastic bag to the connection on the inlet/outlet header then screw the relief valve onto the other end of the elbow.

Seal the threads using Teflon tape, never hemp. A drain line must be installed in accordance with AS/NZS 3500.4 to carry the discharge from the valve to a suitable discharge point.

Relief Valve Pressure Rating

On/Off Models	850 kPa (125 psi)
Hi/Lo Models	310 kPa (45 psi)

Pressure

Relief Valve

When the water heater is connected to a storage cylinder for water heating applications, a correctly sized and pressure rated TPR valve MUST be fitted to the storage cylinder.

NOTE: Where a Hi/Lo water heater is used in a water heating application it will be necessary to replace the 310 kPa relief valve provided with the water heater with one rated at 850 kPa.

RELIEF VALVE DRAIN

A copper drain line must be fitted to the relief valve to carry the discharge clear of the water heater. Connect the drain line to the relief valve using a disconnection union. The pipe work from the relief valve to the drain should be as short as possible and fall all the way from the water heater with no restrictions. It should have no more than three right angle bends in it. Use DN20 pipe.

The outlet of the drain line must be in such a position that flow out of the pipe can be easily seen (refer to AS/NZS 3500.4) - but arranged so hot water discharge will not cause injury, damage or nuisance. The drain line must discharge at an outlet or air break not more than 9 metres from the relief valve.

In locations where water pipes are prone to freezing, the drain line must be insulated and not exceed 300 mm in length. In this instance, the drain line is to discharge into a tundish through an air gap of between 75 mm and 150 mm.

WARNING: The pressure relief valve on this water heater may discharge high temperature water under certain conditions, it is strongly recommended the pipe work downstream of the relief valve be capable of carrying water exceeding 93°C. Failure to observe this precaution may result in damage to pipe work and property.

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