KABLAY

Category: Plumbing

Hydroaccumulator installation

A hydroaccumulator is a sealed tank with an internal diaphragm that stores water under pressure. In Israel, it's installed in private homes (villas) with a well/borehole pump, in apartments with a dedicated booster pump, and in systems with recurring water hammer. A properly sized and installed pressure tank means a quieter pump, stable pressure, and protection from unnecessary wear.

Why a hydroaccumulator is needed

Three main jobs:

  1. Fewer pump starts. Without a tank, the pump kicks in every time you open a tap. With a tank — it fills the tank under pressure, then feeds fixtures from the tank. The pump cycles 3–5 times an hour instead of 30–50. Service life goes up 5–10×.
  2. Pressure stabilization. You open a tap, pressure drops — the tank compensates from its reserve while the pump spins up. The stream doesn't stutter.
  3. Water-hammer protection. The diaphragm absorbs sharp pressure spikes — pipes and fixtures last longer.

Where it's installed

Private home with a well/borehole pump

Mandatory. Without a tank, the pump "burns out" in 2–3 years from endless cycling. With a 50–100 L tank, it runs for 10–15 years.

Apartment with a booster pump

In old apartment buildings, top floors suffer from weak pressure — a small booster pump is installed (with a 20–50 L tank). The tank is mandatory.

Home with a well as backup supply

When switching between "mains / well," the tank smooths the transitions.

Yard irrigation system

With a dedicated pump — a small 20–50 L tank for drip irrigation.

Before a boiler with a solenoid valve

Sometimes a 5–10 L expansion tank is fitted to compensate thermal expansion — functionally similar, but not quite a hydroaccumulator.

Sizing the tank

Tank volume is selected based on pump output and consumption profile:

  • Apartment, 1–2 draw-off points — 20–24 L is enough.
  • 3–4 room home on a well — 50–80 L standard.
  • Large home with 2–3 bathrooms — 100–150 L.
  • Home + garden + irrigation — 150–200 L, sometimes several tanks in parallel.

Rule of thumb: tank volume = pump output per minute × 3–5. A pump delivering 40 L/min → a 120–200 L tank.

Orientation — horizontal or vertical

  • Vertical — takes less space, sits in a corner. Standard for smaller tanks (up to 50 L).
  • Horizontal — more stable stance, pump mounts on top. For tanks 80+ L.

Connection diagram

Standard diagram for a private home:

  1. Pump — draws from the well/borehole.
  2. Check valve — right after the pump, so water doesn't drain back into the well.
  3. Five-way fitting — where the pump, tank, gauge, pressure switch, and line to fixtures meet.
  4. Hydroaccumulator — on one port of the fitting.
  5. Pressure switch — starts/stops the pump on pressure drop/rise.
  6. Pressure gauge — visual check.
  7. Line to fixtures — on into the home distribution.

Air pressure in the diaphragm

The air side of the diaphragm is pre-charged 0.2–0.3 bar below the pump cut-in pressure. For example, pump turns on at 2 bar, off at 3 bar — diaphragm at 1.8 bar. Incorrect pre-charge is the main cause of premature diaphragm wear.

How the installation goes

  1. Choose the location. Flat surface, service access, a power outlet nearby (for the pump). For heavy tanks (50+ kg) — check floor load capacity.
  2. Check diaphragm pressure before connection (with a gauge on the valve). Top up or bleed as needed.
  3. Assemble the manifold — five-way fitting, pressure switch, gauge, tank.
  4. Connect to the pump and to the mains — on threaded joints with sealing.
  5. Tune the pressure switch — upper (cut-out) and lower (cut-in) limits. Usually 1.5/3 bar or 2/4 bar.
  6. Power up and test. Open a tap, watch the pump start/stop behavior.

Pricing in Israel

  • 24 L hydroaccumulator (small apartment) — 250–450 ILS hardware + 300–500 ILS labor
  • 50 L hydroaccumulator — 400–700 ILS + 400–700 ILS labor
  • 80–100 L hydroaccumulator — 600–1,200 ILS + 500–900 ILS labor
  • 150–200 L — 1,000–2,000 ILS + 700–1,400 ILS
  • Full "pump + tank + switch + automation" installation from scratch — 2,500–6,000 ILS labor + hardware
  • Replacing the diaphragm in an old tank — 150–400 ILS labor + 80–250 ILS diaphragm (if the part is available)
  • Pre-charging the diaphragm (scheduled or on pressure loss) — 150–250 ILS

Popular models in Israel

  • Aquasystem (Italy) — premium, wide range, 10+ years.
  • Varem (Italy) — reliable mid-range.
  • Reflex (Germany) — quality, availability.
  • Zilmet (Italy) — good price/quality ratio.
  • Jeelex, Vikhr — ex-USSR brands, less common.
  • Chinese no-name — lasts 2–4 years, half the price. For temporary solutions.

Common issues and maintenance

  • Pump cycles frequently. Diaphragm pressure has dropped — pre-charge via the valve with a car tire pump.
  • "Wet" charge valve. The diaphragm is ruptured — water has entered the air side. Diaphragm or whole-tank replacement.
  • Noise from the tank. Limescale has built up inside — heavy fouling damages the diaphragm. Prevention — inlet filter.
  • Tank "feels full" but is empty. Air trap or ruptured diaphragm — water stays stuck.

Maintenance: check diaphragm pressure annually, replace the diaphragm every 3–5 years. Tank life — 10–15 years with proper care.

FAQ

Is a hydroaccumulator mandatory in a private home?

With a well/borehole pump — practically yes. Without a tank, the pump runs to failure and burns out in 2–3 years. A tank at 500–1,500 ILS vs a pump at 1,500–4,000 ILS — pays back quickly. Going without a tank is acceptable only with variable-frequency pumps (more expensive).

My pressure tank is 8 years old. Should I replace it preventively?

If it runs stably, the diaphragm holds pressure, no moisture at the valve — leave it alone. But check pressure yearly and listen to the pump. The first warning sign is increased cycling frequency. Then inspect the diaphragm.

Can I use a heating-system expansion tank for water?

No. Heating tanks have a diaphragm made of material not intended for potable water. Long-term contact — water starts to "smell" of rubber or absorbs additives. For potable water use only purpose-built tanks with food-grade diaphragms (FDA marking / אישור משרד הבריאות).

Where do I put the tank if there's no utility room?

Vertical 24–50 L — in a kitchen cabinet under the sink, in a hall closet, in a plumbing cabinet niche. Key requirement — access to the charge valve and fittings. For larger tanks (80+ L) — a separate room or a technical corner on the property.