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How to install a bronze circulating pump

Updated: 22 October 2026

The new bronze pump has arrived. Isolate the loop, match the unions, stay inside wiring you understand, and commission on the lowest quiet speed. Stop for Gas Safe or Part P work. The unit should be one from the [bronze circulating pump comparison](/hub/heating/bronze-circulating-pump). Loop layout is on the [secondary return bronze pump](/hub/heating/bronze-circulating-pump/sub/bronze-circulating-pump-secondary-return) page. Purchase checks are on the [bronze circulating pump buying guide](/hub/heating/bronze-circulating-pump/sub/bronze-circulating-pump-buying-guide). Peter F. compared amazon.co.uk listings. There was no lab test. A qualifying purchase can earn a commission at no extra cost to you.

The new bronze pump has arrived. Isolate the loop, match the unions, stay inside wiring you understand, and commission on the lowest quiet speed. Stop for Gas Safe or Part P work.

Our top picks

Hanicks Hanicks 97549426

Best overall

Hanicks Hanicks 97549426
10.0/10about £140.00
View offer
Trident Trident TP256-130BR

Best value

Trident Trident TP256-130BR
8.2/10about £89.99
View offer
Unvented Components Europe Unvented Components Europe GPD25-6SQ-130

Rank 3

Unvented Components Europe Unvented Components Europe GPD25-6SQ-130
0.0/10about £94.77
View offer
On this page
  1. 1.Before you open the system
  2. 2.Mechanical swap and unions
  3. 3.Wiring and controls
  4. 4.Commissioning and speed choice
  5. 5.When to stop and call a professional

Before you open the system

Photograph the old label, the union sizes and the flow arrow relative to the non-return valve. Confirm 130 mm port-to-port and 1½ inch BSP. GPD25 prints both. Other rows may leave them blank. Switch the pump off at the fused spur and do not open the wiring cover while it is live. If you cannot isolate the return without emptying the cylinder coil loop, stop. Lay towels and replacement seals if the kit is pump-only. Hanicks lists the pump only. Tower and GPD25 include seals. Read the leaflet in the carton before the first union. This page does not replace that diagram.

Mechanical swap and unions

With the water isolated, loosen both unions. Expect a cupful even after a drain. Remove the old pump without twisting the copper tails. Seat the new one with the flow arrow as before, and as Worcester TB0050 expects: on the return near the cylinder, with the non-return valve blocking reverse flow into the cold path. Use new rubber seals. Crushed seals weep once the loop pressurises. Hand-tighten, then a quarter turn. Over-torque cracks bronze faces. If the unions weep after two careful attempts, stop. A 130 mm unit will not sit on 180 mm centres.
Hanicks Hanicks 97549426

Testsieger

Hanicks Hanicks 97549426
10.0/10about £140.00
View offer

Wiring and controls

These listings are 230 V secondary circulators, usually from a fused spur near the cupboard. If you cannot identify line, neutral and earth, or the spur is shared in a way you cannot map, that is Part P work for a qualified electrician. Fit the cover only when the connections and the strain relief are secure. Note which timer, cylinder stat or demand-switch wire went where before you disconnect. Do not run the pump dry. Fill and vent the loop first. Continuous running versus a timer is an energy and legionella question. HSE hot-water guidance is clear that the pump alone does not answer it.

Commissioning and speed choice

Refill, bleed the high points and restore power. Start on speed 1. GPD25 lists 55 W, 70 W and 100 W. A dry hum after bleeding can mean the speed is too high, or that the non-return valve is fighting the flow. Hot water should arrive sooner at the distant tap without the pump screaming. If TB0050’s layout includes a flow-regulating valve, follow its setting rather than maximum speed. Use speed 2 only if the return is weak. Speed 3 left on all day adds heat loss. UK reviews on budget rows praise quiet running after a low or middle speed, not on first energise.

When to stop and call a professional

Stop for unvented cylinder work you are not certified to touch, any gas storage train you cannot positively isolate, repeated union leaks, or wiring that does not match the diagram in the box. If the distant tap is still cold after a correct swap, the fault may be loop design: insulation, non-return valve orientation, or a missing timer. Another pump from the best bronze circulating pump page will not repair that. Landlords with legionella control plans in care settings need policy advice beyond a pump swap. Keep nameplate photos and invoices. A job that was ordered because the title said WRAS still needs the plate to match the invoice.

Common questions

Do I need to drain the cylinder loop first?
You must depressurise and isolate the secondary loop so the unions can come apart without spraying. How much drains depends on the valve positions. Plan for water even on a small swap.
Which way does the non-return valve face?
It must allow flow from the return toward the cylinder train and block reverse flow into the cold supply path. Photograph the old orientation before you remove it.
Can I wire this myself?
Competent DIYers sometimes do, on a dedicated fused spur they understand. If in doubt, use a qualified electrician under Part P rules.
What speed should I leave the pump on after commissioning?
The lowest speed that gives acceptable hot water at the distant tap without noise. Avoid leaving speed 3 on all day unless the controls strategy requires it.
Does the pump belong on the flow or the return pipe?
Manufacturer diagrams for secondary domestic hot water place the bronze pump on the return branch near the cylinder, with the non-return valve in the prescribed position. Mirror TB0050, not radiator habits.
When is Gas Safe required?
When the work touches the gas-fired cylinder train, the flue, or controls you are not qualified to alter. A pump-only swap on a piped secondary return may stay in plumbing and electrical scope if you can isolate safely. If you are unsure, ask.

Related pages

WRAS approved bronze circulating pump

Bronze circulating pump

Best bronze circulating pump for a UK secondary loop

Bronze circulating pump buying guide: fit and WRAS

Secondary return bronze pump: loop layout and duty

Sources

Public UK sources named below. amazon.co.uk prices, stars and review counts on these six listings were taken from the listing files. Page updated October 2026.

  1. Wilo UK: bronze vs stainless domestic hot water pumps (retrieved October 2026)
  2. Worcester Bosch TB0050 secondary circulation (retrieved October 2026)
  3. HSE HSG274 Part 2: hot and cold water systems (retrieved October 2026)
  4. Archergas DHW15 reference duty (retrieved October 2026)
  5. BritTherm bronze circulator use cases (retrieved October 2026)
  6. Approved Document G (2024 amendments) (retrieved October 2026)
  7. amazon.co.uk listings for the six retained pumps (retrieved October 2026)