Zeus Maior 24 Instructions
Mains water pressurised unvented system are generally not permitted in Ireland. A cold water storage tank
and a pressure boosting pump will normally provide a pressurised cold water supply. The pressurisation
pump should provide a water pressure of between 1 and 3 bar. However, all taps and mixing valves used
with the hot water system must be suitable for operating at a pressure of up to 5.5 bar.
To ensure economic use, the pipe runs between the boiler and taps should be in 15 mm copper pipe and be
as short as possible. Where possible the pipe work should be insulated to reduce heat loss.
Before the cold water supply pipe is connected to the boiler, it should be thoroughly flushed out to avoid the
danger of dirt or foreign matter entering the boiler.
The stored water temperature is adjustable to a maximum of 55°C. In hard water areas this should avoid
possible scale build-up. However, if descaling is necessary contact RVR Limited for guidance.
Unvented Hot Water Storage System
The installation is subject to Building Regulations and the Water Bye Laws of the Local Authority.
The Immergas Zeus Maior 24 boiler is supplied with all the components required for a safe and efficient
unvented hot water system. An air cushion which is present at the top of the 60l storage vessel provides
sufficient expansion for the domestic hot water system. An optional additional DHW expansion kit is avail-
able for situations where the inlet pressure exceeds 3 bar or other situations where the expansion capacity
may not be adequate.
NOTE: In the Dublin City Council area the optional expansion vessel must be fitted to comply with
the approval requirements of the council. The council also requires that the minimum internal di-
ameter of pipes connected to the boiler DHW connections should not be less that 13mm. As 1/2”
thermoplastic pipe does not provide the minimum diameter, the minimum suitable thermoplastic
pipe size is 3/4”
Discharge pipe -
The discharge pipes from the expansion relief valves must be routed to a tundish in
1/2” (or 15 mm )pipe. The discharge pipe work from both relief valves may be joined together in the same
sized pipe, providing at least 3/4” (or 22 mm) pipe work is connected downstream of the tundish.
Tundish -
The tundish must be positioned within 500 mm of the appliance, so that it is visible to the User
and away from electrical devices. The minimum size of the discharge pipe downstream of the tundish is
given in the following table.
Zeus Maior Boiler
Booster
pump
Cold
Water
Supply
Optional
Expansion
Vessel
Primary
expansion
valve
DHW
expansion
valve
Divertor
Valve
Expansion volume
Tundish
Check
Valve
Domestic Hot Water System
15mm (1/2”)
22mm (3/4”)
28mm (1”)
35mm (11/4”)
