Immergas INOXSTOR 200, Installation, Usage And Maintenance Instructions

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Inoxstor Pre-Plumbed Water Heater

Installation, Usage and Maintenance Instructions

3.5  DISCHARGE PIPES FROM SAFETY VALVES

3.5.1  TUNDISH INSTALLATION

The discharge pipes must be routed to a tundish.

The pipe diameter must be selected from the table below.  For D1 (Valve to tundish), at least 15mm piping must be used.  For 

D2 (downstream of the tundish), include the resistance created by each elbow or bend when calculating the length, and select 

an appropriate pipe size according to table 3 below.

The tundish must be positioned vertically, within 500 mm of the unit, clearly visible to the user and away from electrical devices. 

Legend

Purpose

Minimum pipe size

Resistance created by 

each elbow or bend

D1

Valve to tundish

15mm

D2

Tundish to drain

Up to 9m: 22mm

0.8m

Up to 18m: 28mm

1.0m

Up to 27m: 35mm

1.4m

The discharge pipework from the tundish:

▪

Must fall continuously through its length.

▪

Must be of a heat resistant material, e.g. metal. 

▪

Must not be fitted with any valves or taps.

▪

Must discharge to a safe visible position, e.g. onto the surface of an external wall or into a gulley.

▪

Must have a minimum of 300 mm straight pipework directly from the tundish.

Note: Where children may play or otherwise come into contact with discharges, a wire cage or similar guard must be positioned 

to prevent contact whilst maintaining visibility.

Where a single pipe serves a number of discharges, such as in blocks of flats, the number served should be limited to not more 

than 6 systems so that any tundish installation can be traced easily.

If a single common discharge pipe is used then it should be at least one pipe size larger than the largest individual discharge 

pipe to be connected. If the system is installed where discharges from safety devices may not be apparent, i.e. in dwellings oc-

cupied by blind, infirm or disabled people, consideration should be given to the installation of an electronically operated device 

to warn when discharge takes place.

Figure 4 

Discharge  

Pipe Routing

Table 3 - Discharge Pipe Sizing

Figure 5 - High level termination of discharge

3.5.2  HIGH LEVEL TERMINATION OF DISCHARGE

At high level, discharge onto a roof is acceptable providing the roof is capable of withstanding high temperatures and there 

is a distance of 3 m from any plastic guttering systems that would collect such discharge.  

Note: The discharge may consist of scalding water and steam. Asphalt, roofing felt and non-metallic material may be dam

-

aged by such discharges.