Supply And Return Piping - Riello Array AR 3000 Installation And Operation Manual

2.6 Supply and return piping

The Array Boiler utilizes 4" flanges, for both models AR 3000 and
AR 4000, for the water system supply and return piping connec-
tions. The physical location of the supply and return piping con-
nections is on the top of the unit as shown in Fig. 7.
Gas
connection
Fig. 7 Array AR 3000 and AR 4000 Connections
Excessive water hardness causing a lime buildup in the stainless
steel coils or tubes is not a fault of the appliance and is not cov-
ered by warranty. Water hardness must fall within the following
limits:
STEEL BOILERS - With furnace power > 500kBTU/h
ph
Hardness ppm
Electrical Conduc-
ppm
tivity
Chlorides ppm
Sulphides ppm
Nitrides ppm
Oxygen in Solution ppm
Iron ppm
Water
Return
Water
Supply
Water used Water with
for first filling system operating
6 - 8 7.5 – 9.5
< 50 < 50
< 67
< 10
< 10
< 10
< 0.5
− Use only untreated water to fill the system.
− Do not use TSP (tri-sodium phosphate).
− Do not use fill water treated with salt bedding type ex-
changers (ion exchanger).
− Never introduce non-approved boiler treatment or similar
additives.
− Consult a local water treatment specialist for recommenda-
tions if any of the above is outside the stated ranges.
− When using oxygen permeable PEX, the system must be
separated from the boiler by a heat exchanger.
− A correctly sized and working expansion vessel must be in-
stalled.
− Do not exceed the maximum permissible flow rate through
the boiler. Excessive flow can cause erosion damage to the
heat exchanger.
9
CAUTION: Before connecting the boiler to the heating system,
flush the heating system to remove sediment, flux, dirt, and
other foreign matter. The heat exchanger may be damaged by
sediment or corrosion.
9
CAUTION: Do not use cleaning fluids that are not compatible
with the boiler materials, including acids (e.g. hydrochloric
acid and similar ones) at any concentration.
9
CAUTION: Introducing fresh water to the system increases the
oxygen presence and can cause corrosion of metallic compo-
nents. Immediately repair any drips or leaks in the system to
avoid constant introduction of air into the system.
9
CAUTION: Excessive fluctuation in pressure changes in the sys-
tem can cause fatigue and stress on the heat exchanger. This
is detrimental to the integrity of the boiler and system com-
ponents, it is mandatory to maintain a constant operating
pressure.
9
CAUTION: For freeze protection use only propylene glycol, with
scale inhibitors, with a maximum volume [concentration] of
50% of glycol. Frost protection and inhibitor level has to be
checked annually during the regular scheduled maintenance
of the condensing boiler.
A minimum water pressure is required for optimum performance.
Minimum water pressure required: 7.25 psi (0.5 bar).
9
INSTALLATION