26
MULTIPLE INSTALLATIONS
A multiple installation of Solahart 26 litre gas booster water heaters on a single manifold is possible,
using the Equa-Flow
®
manifold system, where large volumes of hot water are required. The Equa-Flow
principle will function with water heaters in line, around a corner or in rows back to back. A recirculated
flow and return system cannot be used.
The solar preheat water and hot water manifolds must be designed to balance the flow from each water
heater. To achieve this, there are basic installation requirements and principles which must be followed:
1. The maximum number of gas booster water heaters in a bank should be 6. Only one bank can be
installed.
2. The hot water line from the manifold must leave from the opposite end to which the solar preheat
water line enters the manifold.
3. The gas booster water heaters must be of the same model.
4. The solar preheat water line, solar preheat and hot headers and hot water line must be sized to
meet the requirements of both AS/NZS 3500.4 and the application. Suggested pipe sizes are:
No
of
gas
boosters
1 2 3 4 5 6
Solar preheat and hot header pipe size DN20 DN25 DN25 DN32 DN40 DN40
Gas pipe size
DN20
DN25 DN25 DN32 DN40 DN40
5. A full flow gate valve or ball valve must be installed on the solar preheat water line to the system. A
non return valve or stop tap must not be installed.
6. A full flow gate valve or ball valve (not a stop tap) must be installed on both the solar preheat water
branch and hot water branch of each water heater.
7. An isolation valve must be installed on the gas branch of each water heater.
8. An adjustable pressure reducing valve (PRV) (RMC model SYR 312 / 20) must be installed on the
solar preheat branch to all but the first water heater. Each PRV is to be adjusted so that each
subsequent water heater is staged to operate only after the required hot water flow rate increases
by intervals of 13 litres per minute (refer to “Pressure Reducing Valve Commissioning Procedure”
on page ).
9. Non return valves or pressure limiting valves
must not
be installed on the branch lines to the water
heaters.
10. All fittings, valves and branch lines must be matched sets all the way along the manifold.
11. Sufficient space must be left to enable access, servicing or removal of any water heater. The water
heaters must be spaced at minimum 560 mm centres (210 mm between each gas booster water
heater) to provide the required clearance between flue terminals.
Refer to the diagram on
page
29 for installation and plant layout details.
